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  • 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
  • Catalysis
  • Nature Publishing Group (NPG)  (94)
  • American Chemical Society (ACS)
  • American Physical Society
  • Cell Press
  • MDPI Publishing
  • Springer Science + Business Media
  • 1
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    Hydroxyapatite catalyzed hydrothermal liquefaction transforms food waste from an environmental liability to renewable fuel (2023)
    Cell Press
    Details
    Publication Date: 2023-03-08
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in LeClerc, H., Tompsett, G., Paulsen, A., McKenna, A., Niles, S., Reddy, C., Nelson, R., Cheng, F., Teixeira, A., & Timko, M. Hydroxyapatite catalyzed hydrothermal liquefaction transforms food waste from an environmental liability to renewable fuel. IScience, 25(9), (2022): 104916, https://doi.org/10.1016/j.isci.2022.104916.
    Description: Food waste is an abundant and inexpensive resource for the production of renewable fuels. Biocrude yields obtained from hydrothermal liquefaction (HTL) of food waste can be boosted using hydroxyapatite (HAP) as an inexpensive and abundant catalyst. Combining HAP with an inexpensive homogeneous base increased biocrude yield from 14 ± 1 to 37 ± 3%, resulting in the recovery of 49 ± 2% of the energy contained in the food waste feed. Detailed product analysis revealed the importance of fatty-acid oligomerization during biocrude formation, highlighting the role of acid-base catalysts in promoting condensation reactions. Economic and environmental analysis found that the new technology has the potential to reduce US greenhouse gas emissions by 2.6% while producing renewable diesel with a minimum fuel selling price of $1.06/GGE. HAP can play a role in transforming food waste from a liability to a renewable fuel.
    Description: This work was funded by the DOE Bioenergy Technology Office (DE-EE0008513), a DOE DBIR (DE-SC0015784) and the MassCEC. The authors thank WenWen Yao, Department of Environmental Science at WPI, for TOC analysis, Mainstream Engineering for heating value characterization of the oil and solid samples, Wei Fan for assistance in obtaining SEM images and, Julia Martin and Ronald Grimm for their assistance in collecting XPS data, and Jeffrey R. Page for his assistance with oil upgrading and analysis. HOL was partially funded for this work by NSF Graduate Research Fellowship award number 2038257. A portion of this work was performed at the National High Magnetic Field Laboratory Ion Cyclotron Resonance user facility, which is supported by the NSF Division of Materials Research and Division of Chemistry through DMR 16-44779 and the State of Florida.
    Keywords: Chemistry ; Chemical engineering ; Catalysis
    Repository Name: Woods Hole Open Access Server
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  • 2
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    Palladium-catalysed transannular C-H functionalization of alicyclic amines (2016)
    Nature Publishing Group (NPG)
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    Publication Date: 2016-02-18
    Description: Discovering pharmaceutical candidates is a resource-intensive enterprise that frequently requires the parallel synthesis of hundreds or even thousands of molecules. C-H bonds are present in almost all pharmaceutical agents. Consequently, the development of selective, rapid and efficient methods for converting these bonds into new chemical entities has the potential to streamline pharmaceutical development. Saturated nitrogen-containing heterocycles (alicyclic amines) feature prominently in pharmaceuticals, such as treatments for depression (paroxetine, amitifadine), diabetes (gliclazide), leukaemia (alvocidib), schizophrenia (risperidone, belaperidone), malaria (mefloquine) and nicotine addiction (cytisine, varenicline). However, existing methods for the C-H functionalization of saturated nitrogen heterocycles, particularly at sites remote to nitrogen, remain extremely limited. Here we report a transannular approach to selectively manipulate the C-H bonds of alicyclic amines at sites remote to nitrogen. Our reaction uses the boat conformation of the substrates to achieve palladium-catalysed amine-directed conversion of C-H bonds to C-C bonds on various alicyclic amine scaffolds. We demonstrate this approach by synthesizing new derivatives of several bioactive molecules, including varenicline.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Topczewski, Joseph J -- Cabrera, Pablo J -- Saper, Noam I -- Sanford, Melanie S -- F32 GM109479/GM/NIGMS NIH HHS/ -- GM073836/GM/NIGMS NIH HHS/ -- R01 GM073836/GM/NIGMS NIH HHS/ -- England -- Nature. 2016 Mar 10;531(7593):220-4. doi: 10.1038/nature16957. Epub 2016 Feb 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26886789" target="_blank"〉PubMed〈/a〉
    Keywords: Amines/*chemistry ; Carbon/*chemistry ; Catalysis ; *Chemistry Techniques, Synthetic ; Heterocyclic Compounds/chemistry ; Hydrogen/*chemistry ; Nitrogen/chemistry ; Palladium/*chemistry ; Pharmaceutical Preparations/chemical synthesis/chemistry ; Piperidines/chemical synthesis/chemistry ; Varenicline/chemical synthesis/chemistry
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  • 3
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    Iron-catalysed tritiation of pharmaceuticals (2016)
    Nature Publishing Group (NPG)
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    Publication Date: 2016-01-15
    Description: A thorough understanding of the pharmacokinetic and pharmacodynamic properties of a drug in animal models is a critical component of drug discovery and development. Such studies are performed in vivo and in vitro at various stages of the development process--ranging from preclinical absorption, distribution, metabolism and excretion (ADME) studies to late-stage human clinical trials--to elucidate a drug molecule's metabolic profile and to assess its toxicity. Radiolabelled compounds, typically those that contain (14)C or (3)H isotopes, are one of the most powerful and widely deployed diagnostics for these studies. The introduction of radiolabels using synthetic chemistry enables the direct tracing of the drug molecule without substantially altering its structure or function. The ubiquity of C-H bonds in drugs and the relative ease and low cost associated with tritium ((3)H) make it an ideal radioisotope with which to conduct ADME studies early in the drug development process. Here we describe an iron-catalysed method for the direct (3)H labelling of pharmaceuticals by hydrogen isotope exchange, using tritium gas as the source of the radioisotope. The site selectivity of the iron catalyst is orthogonal to currently used iridium catalysts and allows isotopic labelling of complementary positions in drug molecules, providing a new diagnostic tool in drug development.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yu, Renyuan Pony -- Hesk, David -- Rivera, Nelo -- Pelczer, Istvan -- Chirik, Paul J -- England -- Nature. 2016 Jan 14;529(7585):195-9. doi: 10.1038/nature16464.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA. ; Merck Research Laboratories, Rahway, New Jersey 07065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26762456" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Deuterium/chemistry ; Drug Discovery ; Iridium/chemistry ; Iron/*chemistry ; Isotope Labeling/*methods ; Pharmaceutical Preparations/*chemistry/metabolism ; Tritium/*chemistry
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  • 4
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    Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis (2016)
    Nature Publishing Group (NPG)
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    Publication Date: 2016-03-25
    Description: Olefin metathesis has had a large impact on modern organic chemistry, but important shortcomings remain: for example, the lack of efficient processes that can be used to generate acyclic alkenyl halides. Halo-substituted ruthenium carbene complexes decompose rapidly or deliver low activity and/or minimal stereoselectivity, and our understanding of the corresponding high-oxidation-state systems is limited. Here we show that previously unknown halo-substituted molybdenum alkylidene species are exceptionally reactive and are able to participate in high-yielding olefin metathesis reactions that afford acyclic 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by small amounts of a catalyst that is generated in situ and used with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents, and proceed to high conversion at ambient temperature within four hours. We obtain many alkenyl chlorides, bromides and fluorides in up to 91 per cent yield and complete Z selectivity. This method can be used to synthesize biologically active compounds readily and to perform site- and stereoselective fluorination of complex organic molecules.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4858352/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4858352/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Koh, Ming Joo -- Nguyen, Thach T -- Zhang, Hanmo -- Schrock, Richard R -- Hoveyda, Amir H -- GM-57212/GM/NIGMS NIH HHS/ -- GM-59426/GM/NIGMS NIH HHS/ -- R01 GM059426/GM/NIGMS NIH HHS/ -- England -- Nature. 2016 Mar 24;531(7595):459-65. doi: 10.1038/nature17396.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA. ; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27008965" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemical synthesis/*chemistry ; Biological Products/chemical synthesis/chemistry ; Bromides/*chemical synthesis/chemistry ; Catalysis ; Chlorides/*chemical synthesis/chemistry ; Fluorides/*chemical synthesis/chemistry ; *Halogenation ; Molybdenum/chemistry
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  • 5
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    Copper-catalysed enantioselective stereodivergent synthesis of amino alcohols (2016)
    Nature Publishing Group (NPG)
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    Publication Date: 2016-03-29
    Description: The chirality, or 'handedness', of a biologically active molecule can alter its physiological properties. Thus it is routine procedure in the drug discovery and development process to prepare and fully characterize all possible stereoisomers of a drug candidate for biological evaluation. Despite many advances in asymmetric synthesis, developing general and practical strategies for obtaining all possible stereoisomers of an organic compound that has multiple contiguous stereocentres remains a challenge. Here, we report a stereodivergent copper-based approach for the expeditious construction of amino alcohols with high levels of chemo-, regio-, diastereo- and enantioselectivity. Specifically, we synthesized these amino-alcohol products using sequential, copper-hydride-catalysed hydrosilylation and hydroamination of readily available enals and enones. This strategy provides a route to all possible stereoisomers of the amino-alcohol products, which contain up to three contiguous stereocentres. We leveraged catalyst control and stereospecificity simultaneously to attain exceptional control of the product stereochemistry. Beyond the immediate utility of this protocol, our strategy could inspire the development of methods that provide complete sets of stereoisomers for other valuable synthetic targets.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4844805/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4844805/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shi, Shi-Liang -- Wong, Zackary L -- Buchwald, Stephen L -- GM-58160/GM/NIGMS NIH HHS/ -- R01 GM058160/GM/NIGMS NIH HHS/ -- England -- Nature. 2016 Apr 21;532(7599):353-6. doi: 10.1038/nature17191. Epub 2016 Mar 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27018656" target="_blank"〉PubMed〈/a〉
    Keywords: Amination ; Amino Alcohols/*chemical synthesis/*chemistry ; Catalysis ; *Chemistry Techniques, Synthetic ; Copper/*chemistry ; Molecular Structure ; Stereoisomerism
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  • 6
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    Multistep continuous-flow synthesis of (R)- and (S)-rolipram using heterogeneous catalysts (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-04-17
    Description: Chemical manufacturing is conducted using either batch systems or continuous-flow systems. Flow systems have several advantages over batch systems, particularly in terms of productivity, heat and mixing efficiency, safety, and reproducibility. However, for over half a century, pharmaceutical manufacturing has used batch systems because the synthesis of complex molecules such as drugs has been difficult to achieve with continuous-flow systems. Here we describe the continuous-flow synthesis of drugs using only columns packed with heterogeneous catalysts. Commercially available starting materials were successively passed through four columns containing achiral and chiral heterogeneous catalysts to produce (R)-rolipram, an anti-inflammatory drug and one of the family of gamma-aminobutyric acid (GABA) derivatives. In addition, simply by replacing a column packed with a chiral heterogeneous catalyst with another column packed with the opposing enantiomer, we obtained antipole (S)-rolipram. Similarly, we also synthesized (R)-phenibut, another drug belonging to the GABA family. These flow systems are simple and stable with no leaching of metal catalysts. Our results demonstrate that multistep (eight steps in this case) chemical transformations for drug synthesis can proceed smoothly under flow conditions using only heterogeneous catalysts, without the isolation of any intermediates and without the separation of any catalysts, co-products, by-products, and excess reagents. We anticipate that such syntheses will be useful in pharmaceutical manufacturing.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tsubogo, Tetsu -- Oyamada, Hidekazu -- Kobayashi, Shu -- England -- Nature. 2015 Apr 16;520(7547):329-32. doi: 10.1038/nature14343.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Green &Sustainable Chemistry Social Cooperation Laboratory, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25877201" target="_blank"〉PubMed〈/a〉
    Keywords: Antidepressive Agents ; Catalysis ; Chemistry Techniques, Synthetic/*instrumentation/*methods ; GABA Agonists/chemical synthesis/chemistry ; Molecular Structure ; Rolipram/*chemical synthesis/chemistry ; Stereoisomerism ; gamma-Aminobutyric Acid/analogs & derivatives/chemical synthesis/chemistry
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  • 7
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    Multimetallic catalysed cross-coupling of aryl bromides with aryl triflates (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-08-19
    Description: The advent of transition-metal catalysed strategies for forming new carbon-carbon bonds has revolutionized the field of organic chemistry, enabling the efficient synthesis of ligands, materials, and biologically active molecules. In cases where a single metal fails to promote a selective or efficient transformation, the synergistic cooperation of two distinct catalysts--multimetallic catalysis--can be used instead. Many important reactions rely on multimetallic catalysis, such as the Wacker oxidation of olefins and the Sonogashira coupling of alkynes with aryl halides, but this approach has largely been limited to the use of metals with distinct reactivities, with only one metal catalyst undergoing oxidative addition. Here, we demonstrate that cooperativity between two group 10 metal catalysts--(bipyridine)nickel and (1,3-bis(diphenylphosphino)propane)palladium--enables a general cross-Ullmann reaction (the cross-coupling of two different aryl electrophiles). Our method couples aryl bromides with aryl triflates directly, eliminating the use of arylmetal reagents and avoiding the challenge of differentiating between multiple carbon-hydrogen bonds that is required for direct arylation methods. Selectivity can be achieved without an excess of either substrate and originates from the orthogonal reactivity of the two catalysts and the relative stability of the two arylmetal intermediates. While (1,3-bis(diphenylphosphino)propane)palladium reacts preferentially with aryl triflates to afford a persistent intermediate, (bipyridine)nickel reacts preferentially with aryl bromides to form a transient, reactive intermediate. Although each catalyst forms less than 5 per cent cross-coupled product in isolation, together they are able to achieve a yield of up to 94 per cent. Our results reveal a new method for the synthesis of biaryls, heteroaryls, and dienes, as well as a general mechanism for the selective transfer of ligands between two metal catalysts. We anticipate that this reaction will simplify the synthesis of pharmaceuticals, many of which are currently made with pre-formed organometallic reagents, and lead to the discovery of new multimetallic reactions.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4552586/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4552586/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ackerman, Laura K G -- Lovell, Matthew M -- Weix, Daniel J -- R01 GM097243/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Aug 27;524(7566):454-7. doi: 10.1038/nature14676. Epub 2015 Aug 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26280337" target="_blank"〉PubMed〈/a〉
    Keywords: Bromides/*chemistry ; Carbon/chemistry ; Catalysis ; Hydrogen/chemistry ; Indicators and Reagents ; Nickel/*chemistry ; Palladium/*chemistry ; Phosphines/chemistry ; Propane/analogs & derivatives/chemistry ; Substrate Specificity
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  • 8
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    Metal-catalysed azidation of tertiary C-H bonds suitable for late-stage functionalization (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-01-30
    Description: Many enzymes oxidize unactivated aliphatic C-H bonds selectively to form alcohols; however, biological systems do not possess enzymes that catalyse the analogous aminations of C-H bonds. The absence of such enzymes limits the discovery of potential medicinal candidates because nitrogen-containing groups are crucial to the biological activity of therapeutic agents and clinically useful natural products. In one prominent example illustrating the importance of incorporating nitrogen-based functionality, the conversion of the ketone of erythromycin to the -N(Me)CH2- group in azithromycin leads to a compound that can be dosed once daily with a shorter treatment time. For such reasons, synthetic chemists have sought catalysts that directly convert C-H bonds to C-N bonds. Most currently used catalysts for C-H bond amination are ill suited to the intermolecular functionalization of complex molecules because they require excess substrate or directing groups, harsh reaction conditions, weak or acidic C-H bonds, or reagents containing specialized groups on the nitrogen atom. Among C-H bond amination reactions, those forming a C-N bond at a tertiary alkyl group would be particularly valuable, because this linkage is difficult to form from ketones or alcohols that might be created in a biosynthetic pathway by oxidation. Here we report a mild, selective, iron-catalysed azidation of tertiary C-H bonds that occurs without excess of the valuable substrate. The reaction tolerates aqueous environments and is suitable for the functionalization of complex structures in the late stages of a multistep synthesis. Moreover, this azidation makes it possible to install a range of nitrogen-based functional groups, including those from Huisgen 'click' cycloadditions and the Staudinger ligation. We anticipate that these reactions will create opportunities to modify natural products, their precursors and their derivatives to produce analogues that contain different polarity and charge as a result of nitrogen-containing groups. It could also be used to help identify targets of biologically active molecules by creating a point of attachment--for example, to fluorescent tags or 'handles' for affinity chromatography--directly on complex molecular structures.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311404/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311404/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sharma, Ankit -- Hartwig, John F -- 4R37GM055382/GM/NIGMS NIH HHS/ -- R37 GM055382/GM/NIGMS NIH HHS/ -- S10-RR027172/RR/NCRR NIH HHS/ -- England -- Nature. 2015 Jan 29;517(7536):600-4. doi: 10.1038/nature14127.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25631448" target="_blank"〉PubMed〈/a〉
    Keywords: Amination ; Azides/*chemistry ; Carbon/*chemistry ; Catalysis ; Electrons ; Hydrogen/*chemistry ; Indicators and Reagents/chemistry ; Iron/*chemistry ; Nitrogen/chemistry
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  • 9
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    Yves Chauvin (1930-2015) (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-03-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Basset, Jean-Marie -- England -- Nature. 2015 Mar 12;519(7542):159. doi: 10.1038/519159a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉KAUST Catalysis Center at the King Abdullah University of Science and Technology in Thuwal, Saudi Arabia. He ran the laboratory at the University of Lyon in France where Yves Chauvin worked from 1996 to 2009.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25762275" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Belgium ; Catalysis ; Chemical Industry/history ; Chemistry/*history ; France ; Green Chemistry Technology/history ; History, 20th Century ; History, 21st Century ; Inventions/history ; Nobel Prize
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  • 10
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    Rhodium-catalysed syn-carboamination of alkenes via a transient directing group (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-10-28
    Description: Alkenes are the most ubiquitous prochiral functional groups--those that can be converted from achiral to chiral in a single step--that are accessible to synthetic chemists. For this reason, difunctionalization reactions of alkenes (whereby two functional groups are added to the same double bond) are particularly important, as they can be used to produce highly complex molecular architectures. Stereoselective oxidation reactions, including dihydroxylation, aminohydroxylation and halogenation, are well established methods for functionalizing alkenes. However, the intermolecular incorporation of both carbon- and nitrogen-based functionalities stereoselectively across an alkene has not been reported. Here we describe the rhodium-catalysed carboamination of alkenes at the same (syn) face of a double bond, initiated by a carbon-hydrogen activation event that uses enoxyphthalimides as the source of both the carbon and the nitrogen functionalities. The reaction methodology allows for the intermolecular, stereospecific formation of one carbon-carbon and one carbon-nitrogen bond across an alkene, which is, to our knowledge, unprecedented. The reaction design involves the in situ generation of a bidentate directing group and the use of a new cyclopentadienyl ligand to control the reactivity of rhodium. The results provide a new way of synthesizing functionalized alkenes, and should lead to the convergent and stereoselective assembly of amine-containing acyclic molecules.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636455/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636455/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Piou, Tiffany -- Rovis, Tomislav -- GM80442/GM/NIGMS NIH HHS/ -- R01 GM080442/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Nov 5;527(7576):86-90. doi: 10.1038/nature15691. Epub 2015 Oct 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26503048" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/*chemistry ; Amination ; Amines/*chemistry ; Carbon/*chemistry ; Catalysis ; Hydrogen/*chemistry ; Models, Chemical ; Nitrogen/*chemistry ; Oxidation-Reduction ; Rhodium/*chemistry
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  • 11
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    Ligand-enabled meta-C-H activation using a transient mediator (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-03-11
    Description: Achieving site selectivity in C-H functionalization reactions is a significant challenge, especially when the target C-H bond is distant from existing functional groups. Coordination of a functional group to a metal is often a key driving force and control element in many important reactions including asymmetric hydrogenation, epoxidation and lithiation. Exploitation of this effect has led to the development of a broad range of directed C-H activation reactions. However, these C-H activation methods are limited to proximal C-H bonds, which are spatially and geometrically accessible from the directing functional group. The development of meta-selective C-H functionalizations remains a significant challenge. We recently developed a U-shaped template that can be used to overcome this constraint and have shown that it can be used to selectively activate remote meta-C-H bonds. Although this approach has proved to be applicable to various substrates and catalytic transformations, the need for a covalently attached, complex template is a substantial drawback for synthetic applications. Here we report an alternative approach employing norbornene as a transient mediator to achieve meta-selective C-H activation with a simple and common ortho-directing group. The use of a newly developed pyridine-based ligand is crucial for relaying the palladium catalyst to the meta position by norbornene after initial ortho-C-H activation. This catalytic reaction demonstrates the feasibility of switching ortho-selectivity to meta-selectivity in C-H activation of the same substrate by catalyst control.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4368492/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4368492/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, Xiao-Chen -- Gong, Wei -- Fang, Li-Zhen -- Zhu, Ru-Yi -- Li, Suhua -- Engle, Keary M -- Yu, Jin-Quan -- 1R01 GM102265/GM/NIGMS NIH HHS/ -- R01 GM102265/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Mar 19;519(7543):334-8. doi: 10.1038/nature14214. Epub 2015 Mar 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25754328" target="_blank"〉PubMed〈/a〉
    Keywords: Alkylation ; Amides/chemistry ; Carbon/*chemistry ; Catalysis ; Halogens/chemistry ; Hydrogen/*chemistry ; Ligands ; Norbornanes/chemistry ; Palladium/chemistry ; Pyridines/chemistry
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  • 12
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    Richard Heck (1931-2015) (2015)
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    Publication Date: 2015-11-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Snieckus, Victor -- England -- Nature. 2015 Nov 19;527(7578):306. doi: 10.1038/527306a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Queen's University, Ontario, Canada. Richard Heck worked in his laboratories in 2006.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26581284" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chemistry/*history ; Chemistry Techniques, Synthetic/*history ; Click Chemistry/history ; History, 20th Century ; History, 21st Century ; Nobel Prize ; Palladium/chemistry/history ; United States
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  • 13
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    Dosage delivery of sensitive reagents enables glove-box-free synthesis (2015)
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    Publication Date: 2015-08-14
    Description: Contemporary organic chemists employ a broad range of catalytic and stoichiometric methods to construct molecules for applications in the material sciences, and as pharmaceuticals, agrochemicals, and sensors. The utility of a synthetic method may be greatly reduced if it relies on a glove box to enable the use of air- and moisture-sensitive reagents or catalysts. Furthermore, many synthetic chemistry laboratories have numerous containers of partially used reagents that have been spoiled by exposure to the ambient atmosphere. This is exceptionally wasteful from both an environmental and a cost perspective. Here we report an encapsulation method for stabilizing and storing air- and moisture-sensitive compounds. We demonstrate this approach in three contexts, by describing single-use capsules that contain all of the reagents (catalysts, ligands, and bases) necessary for the glove-box-free palladium-catalysed carbon-fluorine, carbon-nitrogen, and carbon-carbon bond-forming reactions. This strategy should reduce the number of error-prone, tedious and time-consuming weighing procedures required for such syntheses and should be applicable to a wide range of reagents, catalysts, and substrate combinations.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4536573/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4536573/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sather, Aaron C -- Lee, Hong Geun -- Colombe, James R -- Zhang, Anni -- Buchwald, Stephen L -- 1F32GM108092-01A1/GM/NIGMS NIH HHS/ -- F32 GM108092/GM/NIGMS NIH HHS/ -- R01 GM046059/GM/NIGMS NIH HHS/ -- R01GM46059/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Aug 13;524(7564):208-11. doi: 10.1038/nature14654.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26268191" target="_blank"〉PubMed〈/a〉
    Keywords: Amines/chemistry ; Bromides/chemistry ; Carbon/chemistry ; Catalysis ; Chemistry Techniques, Synthetic/*methods ; Fluorine/chemistry ; Indicators and Reagents ; Ligands ; Nitrogen/chemistry ; Organometallic Compounds/chemistry ; Palladium/chemistry ; Waxes/chemistry
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  • 14
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    Non-stabilized nucleophiles in Cu-catalysed dynamic kinetic asymmetric allylic alkylation (2015)
    Nature Publishing Group (NPG)
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    Publication Date: 2015-01-17
    Description: The development of new reactions forming asymmetric carbon-carbon bonds has enabled chemists to synthesize a broad range of important carbon-containing molecules, including pharmaceutical agents, fragrances and polymers. Most strategies to obtain enantiomerically enriched molecules rely on either generating new stereogenic centres from prochiral substrates or resolving racemic mixtures of enantiomers. An alternative strategy--dynamic kinetic asymmetric transformation--involves the transformation of a racemic starting material into a single enantiomer product, with greater than 50 per cent maximum yield. The use of stabilized nucleophiles (pKa 〈 25, where Ka is the acid dissociation constant) in palladium-catalysed asymmetric allylic alkylation reactions has proved to be extremely versatile in these processes. Conversely, the use of non-stabilized nucleophiles in such reactions is difficult and remains a key challenge. Here we report a copper-catalysed dynamic kinetic asymmetric transformation using racemic substrates and alkyl nucleophiles. These nucleophiles have a pKa of 〉/=50, more than 25 orders of magnitude more basic than the nucleophiles that are typically used in such transformations. Organometallic reagents are generated in situ from alkenes by hydrometallation and give highly enantioenriched products under mild reaction conditions. The method is used to synthesize natural products that possess activity against tuberculosis and leprosy, and an inhibitor of para-aminobenzoate biosynthesis. Mechanistic studies indicate that the reaction proceeds through a rapidly isomerizing intermediate. We anticipate that this approach will be a valuable complement to existing asymmetric catalytic methods.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉You, Hengzhi -- Rideau, Emeline -- Sidera, Mireia -- Fletcher, Stephen P -- England -- Nature. 2015 Jan 15;517(7534):351-5. doi: 10.1038/nature14089.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25592541" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Alkylation ; Antitubercular Agents/chemical synthesis/chemistry ; Biological Products/*chemical synthesis/chemistry ; Carbon/*chemistry ; Catalysis ; Copper/*chemistry ; Isomerism ; Kinetics ; Leprosy/drug therapy ; Organometallic Compounds/chemistry ; Palladium/chemistry ; Pharmaceutical Preparations/*chemical synthesis/chemistry ; para-Aminobenzoates/metabolism
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  • 15
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    Silylation of C-H bonds in aromatic heterocycles by an Earth-abundant metal catalyst (2015)
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    Publication Date: 2015-02-06
    Description: Heteroaromatic compounds containing carbon-silicon (C-Si) bonds are of great interest in the fields of organic electronics and photonics, drug discovery, nuclear medicine and complex molecule synthesis, because these compounds have very useful physicochemical properties. Many of the methods now used to construct heteroaromatic C-Si bonds involve stoichiometric reactions between heteroaryl organometallic species and silicon electrophiles or direct, transition-metal-catalysed intermolecular carbon-hydrogen (C-H) silylation using rhodium or iridium complexes in the presence of excess hydrogen acceptors. Both approaches are useful, but their limitations include functional group incompatibility, narrow scope of application, high cost and low availability of the catalysts, and unproven scalability. For this reason, a new and general catalytic approach to heteroaromatic C-Si bond construction that avoids such limitations is highly desirable. Here we report an example of cross-dehydrogenative heteroaromatic C-H functionalization catalysed by an Earth-abundant alkali metal species. We found that readily available and inexpensive potassium tert-butoxide catalyses the direct silylation of aromatic heterocycles with hydrosilanes, furnishing heteroarylsilanes in a single step. The silylation proceeds under mild conditions, in the absence of hydrogen acceptors, ligands or additives, and is scalable to greater than 100 grams under optionally solvent-free conditions. Substrate classes that are difficult to activate with precious metal catalysts are silylated in good yield and with excellent regioselectivity. The derived heteroarylsilane products readily engage in versatile transformations enabling new synthetic strategies for heteroaromatic elaboration, and are useful in their own right in pharmaceutical and materials science applications.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Toutov, Anton A -- Liu, Wen-Bo -- Betz, Kerry N -- Fedorov, Alexey -- Stoltz, Brian M -- Grubbs, Robert H -- England -- Nature. 2015 Feb 5;518(7537):80-4. doi: 10.1038/nature14126.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25652999" target="_blank"〉PubMed〈/a〉
    Keywords: Butanols/*chemistry ; Carbon/*chemistry ; Catalysis ; Cyclization ; Drug Discovery ; Hydrogen/*chemistry ; Indoles/chemistry ; Nitrogen/chemistry ; Oxygen/chemistry ; Potassium/*chemistry ; Silanes/*chemical synthesis/*chemistry ; Silicon/*chemistry
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  • 16
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    Stable gold(III) catalysts by oxidative addition of a carbon-carbon bond (2015)
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    Publication Date: 2015-01-23
    Description: Low-valent late transition-metal catalysis has become indispensable to chemical synthesis, but homogeneous high-valent transition-metal catalysis is underdeveloped, mainly owing to the reactivity of high-valent transition-metal complexes and the challenges associated with synthesizing them. Here we report a carbon-carbon bond cleavage at ambient conditions by a Au(i) complex that generates a stable Au(iii) cationic complex. In contrast to the well-established soft and carbophilic Au(i) catalyst, this Au(iii) complex exhibits hard, oxophilic Lewis acidity. For example, we observed catalytic activation of alpha,beta-unsaturated aldehydes towards selective conjugate additions as well as activation of an unsaturated aldehyde-allene for a [2 + 2] cycloaddition reaction. The origin of the regioselectivity and catalytic activity was elucidated by X-ray crystallographic analysis of an isolated Au(iii)-activated cinnamaldehyde intermediate. The concepts revealed suggest a strategy for accessing high-valent transition-metal catalysis from readily available precursors.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304402/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304402/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, Chung-Yeh -- Horibe, Takahiro -- Jacobsen, Christian Borch -- Toste, F Dean -- R01 GM073932/GM/NIGMS NIH HHS/ -- S10-RR027172/RR/NCRR NIH HHS/ -- England -- Nature. 2015 Jan 22;517(7535):449-54. doi: 10.1038/nature14104.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25612049" target="_blank"〉PubMed〈/a〉
    Keywords: Acrolein/analogs & derivatives/chemistry ; Aldehydes/chemistry ; Alkadienes/chemistry ; Carbon/chemistry ; Catalysis ; Crystallography, X-Ray ; Gold/*chemistry ; Lewis Acids/chemistry ; Models, Molecular ; Molecular Structure ; Oxidation-Reduction
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  • 17
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    Catalytic asymmetric umpolung reactions of imines (2015)
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    Publication Date: 2015-07-24
    Description: The carbon-nitrogen double bonds in imines are fundamentally important functional groups in organic chemistry. This is largely due to the fact that imines act as electrophiles towards carbon nucleophiles in reactions that form carbon-carbon bonds, thereby serving as one of the most widely used precursors for the formation of amines in both synthetic and biosynthetic settings. If the carbon atom of the imine could be rendered electron-rich, the imine could react as a nucleophile instead of as an electrophile. Such a reversal in the electronic characteristics of the imine functionality would facilitate the development of new chemical transformations that convert imines into amines via carbon-carbon bond-forming reactions with carbon electrophiles, thereby creating new opportunities for the efficient synthesis of amines. The development of asymmetric umpolung reactions of imines (in which the imines act as nucleophiles) remains uncharted territory, in spite of the far-reaching impact such reactions would have in organic synthesis. Here we report the discovery and development of new chiral phase-transfer catalysts that promote the highly efficient asymmetric umpolung reactions of imines with the carbon electrophile enals. These catalysts mediate the deprotonation of imines and direct the 2-azaallyl anions thus formed to react with enals in a highly chemoselective, regioselective, diastereoselective and enantioselective fashion. The reaction tolerates a broad range of imines and enals, and can be carried out in high yield with as little as 0.01 mole per cent catalyst with a moisture- and air-tolerant operational protocol. These umpolung reactions provide a conceptually new and practical approach to chiral amino compounds.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513368/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513368/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, Yongwei -- Hu, Lin -- Li, Zhe -- Deng, Li -- GM-61591/GM/NIGMS NIH HHS/ -- R01 GM061591/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Jul 23;523(7561):445-50. doi: 10.1038/nature14617.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26201597" target="_blank"〉PubMed〈/a〉
    Keywords: Acrolein/chemistry ; Air ; Amino Alcohols/chemical synthesis/chemistry ; Carbon/chemistry ; Catalysis ; Chemistry Techniques, Synthetic/*methods ; Electrons ; Humidity ; Imines/*chemistry ; Nitrogen/chemistry
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    Alcohols as alkylating agents in heteroarene C-H functionalization (2015)
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    Publication Date: 2015-08-27
    Description: Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of 'spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4560617/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4560617/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jin, Jian -- MacMillan, David W C -- R01 GM103558/GM/NIGMS NIH HHS/ -- R01 GM103558-03/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Sep 3;525(7567):87-90. doi: 10.1038/nature14885. Epub 2015 Aug 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26308895" target="_blank"〉PubMed〈/a〉
    Keywords: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives/chemistry ; Alcohols/*chemistry ; Alkylating Agents/*chemistry ; Alkylation ; Carbon/*chemistry ; Catalysis ; Hydrogen/*chemistry ; Milrinone/chemistry ; Oxidation-Reduction ; Oxygen/chemistry ; Photochemical Processes ; Substrate Specificity
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    The direct arylation of allylic sp(3) C-H bonds via organic and photoredox catalysis (2015)
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    Publication Date: 2015-03-06
    Description: The direct functionalization of unactivated sp(3) C-H bonds is still one of the most challenging problems facing synthetic organic chemists. The appeal of such transformations derives from their capacity to facilitate the construction of complex organic molecules via the coupling of simple and otherwise inert building blocks, without introducing extraneous functional groups. Despite notable recent efforts, the establishment of general and mild strategies for the engagement of sp(3) C-H bonds in C-C bond forming reactions has proved difficult. Within this context, the discovery of chemical transformations that are able to directly functionalize allylic methyl, methylene and methine carbons in a catalytic manner is a priority. Although protocols for direct oxidation and amination of allylic C-H bonds (that is, C-H bonds where an adjacent carbon is involved in a C = C bond) have become widely established, the engagement of allylic substrates in C-C bond forming reactions has thus far required the use of pre-functionalized coupling partners. In particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug's action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C-H arylation. This C-C bond forming reaction readily accommodates a broad range of alkene and electron-deficient arene reactants, and has been used in the direct arylation of benzylic C-H bonds.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4378681/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4378681/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuthbertson, James D -- MacMillan, David W C -- R01 GM103558/GM/NIGMS NIH HHS/ -- R01 GM103558-03/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Mar 5;519(7541):74-7. doi: 10.1038/nature14255.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25739630" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Carbon/*chemistry ; Catalysis ; Chemistry Techniques, Synthetic/*methods ; Electrons ; Hydrogen/*chemistry ; Hydrogen Bonding ; Oxidation-Reduction ; Pharmaceutical Preparations/chemistry ; *Photochemical Processes ; Sulfhydryl Compounds/chemistry
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  • 20
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    Fungal pathogen uses sex pheromone receptor for chemotropic sensing of host plant signals (2015)
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    Publication Date: 2015-10-28
    Description: For more than a century, fungal pathogens and symbionts have been known to orient hyphal growth towards chemical stimuli from the host plant. However, the nature of the plant signals as well as the mechanisms underlying the chemotropic response have remained elusive. Here we show that directed growth of the soil-inhabiting plant pathogen Fusarium oxysporum towards the roots of the host tomato (Solanum lycopersicum) is triggered by the catalytic activity of secreted class III peroxidases, a family of haem-containing enzymes present in all land plants. The chemotropic response requires conserved elements of the fungal cell integrity mitogen-activated protein kinase (MAPK) cascade and the seven-pass transmembrane protein Ste2, a functional homologue of the Saccharomyces cerevisiae sex pheromone alpha receptor. We further show that directed hyphal growth of F. oxysporum towards nutrient sources such as sugars and amino acids is governed by a functionally distinct MAPK cascade. These results reveal a potentially conserved chemotropic mechanism in root-colonizing fungi, and suggest a new function for the fungal pheromone-sensing machinery in locating plant hosts in a complex environment such as the soil.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Turra, David -- El Ghalid, Mennat -- Rossi, Federico -- Di Pietro, Antonio -- England -- Nature. 2015 Nov 26;527(7579):521-4. doi: 10.1038/nature15516. Epub 2015 Oct 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departamento de Genetica, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Cordoba, 14071 Cordoba, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26503056" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Fusarium/growth & development/*metabolism ; *Host-Pathogen Interactions ; Hyphae/growth & development/metabolism ; Lycopersicon esculentum/enzymology/*metabolism/*microbiology ; MAP Kinase Signaling System ; Peptides/metabolism ; Peroxidases/*metabolism ; Plant Roots/enzymology/microbiology ; Receptors, Mating Factor/chemistry/*metabolism ; Tropism/*physiology
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    Catalytic enantioselective synthesis of quaternary carbon stereocentres (2014)
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    Publication Date: 2014-12-17
    Description: Quaternary carbon stereocentres-carbon atoms to which four distinct carbon substituents are attached-are common features of molecules found in nature. However, before recent advances in chemical catalysis, there were few methods of constructing single stereoisomers of this important structural motif. Here we discuss the many catalytic enantioselective reactions developed during the past decade for the synthesis of single stereoisomers of such organic molecules. This progress now makes it possible to incorporate quaternary stereocentres selectively in many organic molecules that are useful in medicine, agriculture and potentially other areas such as flavouring, fragrances and materials.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4697831/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4697831/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Quasdorf, Kyle W -- Overman, Larry E -- GM098601/GM/NIGMS NIH HHS/ -- R01 GM030859/GM/NIGMS NIH HHS/ -- R01 GM098601/GM/NIGMS NIH HHS/ -- R01 HL025854/HL/NHLBI NIH HHS/ -- England -- Nature. 2014 Dec 11;516(7530):181-91. doi: 10.1038/nature14007.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697-2025, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25503231" target="_blank"〉PubMed〈/a〉
    Keywords: Agrochemicals/chemical synthesis/chemistry ; Alkylation ; Biological Products/chemical synthesis/chemistry ; Carbon/*chemistry ; Catalysis ; *Chemistry Techniques, Synthetic ; Cortisone/chemistry ; Cyclization ; Metals/chemistry ; Molecular Structure ; Morphine/chemistry ; Organic Chemicals/*chemical synthesis/*chemistry ; Palladium/chemistry ; Pharmaceutical Preparations/chemical synthesis/chemistry ; Stereoisomerism ; Terpenes/chemical synthesis/chemistry
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    Recent advances in homogeneous nickel catalysis (2014)
    Nature Publishing Group (NPG)
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    Publication Date: 2014-05-16
    Description: Tremendous advances have been made in nickel catalysis over the past decade. Several key properties of nickel, such as facile oxidative addition and ready access to multiple oxidation states, have allowed the development of a broad range of innovative reactions. In recent years, these properties have been increasingly understood and used to perform transformations long considered exceptionally challenging. Here we discuss some of the most recent and significant developments in homogeneous nickel catalysis, with an emphasis on both synthetic outcome and mechanism.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4344729/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4344729/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tasker, Sarah Z -- Standley, Eric A -- Jamison, Timothy F -- GM62755/GM/NIGMS NIH HHS/ -- R01 GM063755/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 May 15;509(7500):299-309. doi: 10.1038/nature13274.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA [2]. ; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24828188" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; *Chemistry Techniques, Synthetic ; Chemistry, Organic ; Nickel/*chemistry ; Oxidation-Reduction
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    Copper rewired (2014)
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    Publication Date: 2014-04-12
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉England -- Nature. 2014 Apr 10;508(7495):150.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24724184" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carbon Dioxide/*chemistry ; Catalysis ; Chelating Agents/therapeutic use ; Copper/*chemistry ; Ethanol/*chemical synthesis/chemistry ; Hepatolenticular Degeneration/drug therapy/metabolism ; Humans ; Mice ; Neoplasms/*drug therapy/genetics/*metabolism/pathology ; Proto-Oncogene Proteins B-raf/genetics ; Renewable Energy
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    Multifunctional organoboron compounds for scalable natural product synthesis (2014)
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    Publication Date: 2014-09-19
    Description: Efficient catalytic reactions that can generate C-C bonds enantioselectively, and ones that can produce trisubstituted alkenes diastereoselectively, are central to research in organic chemistry. Transformations that accomplish these two tasks simultaneously are in high demand, particularly if the catalysts, substrates and reagents are inexpensive and if the reaction conditions are mild. Here we report a facile multicomponent catalytic process that begins with a chemoselective, site-selective and diastereoselective copper-boron addition to a monosubstituted allene; the resulting boron-substituted organocopper intermediates then participate in a similarly selective allylic substitution. The products, which contain a stereogenic carbon centre, a monosubstituted alkene and an easily functionalizable Z-trisubstituted alkenylboron group, are obtained in up to 89 per cent yield, with more than 98 per cent branch-selectivity and stereoselectivity and an enantiomeric ratio greater than 99:1. The copper-based catalyst is derived from a robust heterocyclic salt that can be prepared in multigram quantities from inexpensive starting materials and without costly purification procedures. The utility of the approach is demonstrated through enantioselective synthesis of gram quantities of two natural products, namely rottnestol and herboxidiene (also known as GEX1A).〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4267680/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4267680/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meng, Fanke -- McGrath, Kevin P -- Hoveyda, Amir H -- GM-47480/GM/NIGMS NIH HHS/ -- R01 GM047480/GM/NIGMS NIH HHS/ -- R01 GM057212/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 Sep 18;513(7518):367-74. doi: 10.1038/nature13735.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25230659" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/*chemical synthesis/chemistry ; Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry ; Antineoplastic Agents/chemical synthesis/chemistry ; Biological Products/*chemical synthesis/chemistry ; Boron/chemistry ; Catalysis ; Copper/chemistry ; Fatty Alcohols/*chemical synthesis/chemistry ; Monosaccharides/*chemical synthesis/chemistry ; Porifera/chemistry ; Pyrans/*chemical synthesis/chemistry ; Stereoisomerism
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    Overcoming the limitations of directed C-H functionalizations of heterocycles (2014)
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    Publication Date: 2014-11-11
    Description: In directed C-H activation reactions, any nitrogen or sulphur atoms present in heterocyclic substrates will coordinate strongly with metal catalysts. This coordination, which can lead to catalyst poisoning or C-H functionalization at an undesired position, limits the application of C-H activation reactions in heterocycle-based drug discovery, in which regard they have attracted much interest from pharmaceutical companies. Here we report a robust and synthetically useful method that overcomes the complications associated with performing C-H functionalization reactions on heterocycles. Our approach employs a simple N-methoxy amide group, which serves as both a directing group and an anionic ligand that promotes the in situ generation of the reactive PdX2 (X = ArCONOMe) species from a Pd(0) source using air as the sole oxidant. In this way, the PdX2 species is localized near the target C-H bond, avoiding interference from any nitrogen or sulphur atoms present in the heterocyclic substrates. This reaction overrides the conventional positional selectivity patterns observed with substrates containing strongly coordinating heteroatoms, including nitrogen, sulphur and phosphorus. Thus, this operationally simple aerobic reaction demonstrates that it is possible to bypass a fundamental limitation that has long plagued applications of directed C-H activation in medicinal chemistry.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4248606/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4248606/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Yue-Jin -- Xu, Hui -- Kong, Wei-Jun -- Shang, Ming -- Dai, Hui-Xiong -- Yu, Jin-Quan -- 1R01GM102265/GM/NIGMS NIH HHS/ -- R01 GM102265/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 Nov 20;515(7527):389-93. doi: 10.1038/nature13885. Epub 2014 Nov 10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China. ; 1] State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China [2] Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25383516" target="_blank"〉PubMed〈/a〉
    Keywords: Air ; Amides/chemistry ; Carbon/*chemistry ; Catalysis ; Chemistry, Pharmaceutical/*methods ; Heterocyclic Compounds/*chemistry ; Hydrogen/*chemistry ; Nitrogen/chemistry ; Oxidants/chemistry ; Palladium/chemistry ; Phosphorus/chemistry ; Sulfur/chemistry
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    Interrogating selectivity in catalysis using molecular vibrations (2014)
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    Publication Date: 2014-03-14
    Description: The delineation of molecular properties that underlie reactivity and selectivity is at the core of physical organic chemistry, and this knowledge can be used to inform the design of improved synthetic methods or identify new chemical transformations. For this reason, the mathematical representation of properties affecting reactivity and selectivity trends, that is, molecular parameters, is paramount. Correlations produced by equating these molecular parameters with experimental outcomes are often defined as free-energy relationships and can be used to evaluate the origin of selectivity and to generate new, experimentally testable hypotheses. The premise behind successful correlations of this type is that a systematically perturbed molecular property affects a transition-state interaction between the catalyst, substrate and any reaction components involved in the determination of selectivity. Classic physical organic molecular descriptors, such as Hammett, Taft or Charton parameters, seek to independently probe isolated electronic or steric effects. However, these parameters cannot address simultaneous, non-additive variations to more than one molecular property, which limits their utility. Here we report a parameter system based on the vibrational response of a molecule to infrared radiation that can be used to mathematically model and predict selectivity trends for reactions with interlinked steric and electronic effects at positions of interest. The disclosed parameter system is mechanistically derived and should find broad use in the study of chemical and biological systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Milo, Anat -- Bess, Elizabeth N -- Sigman, Matthew S -- England -- Nature. 2014 Mar 13;507(7491):210-4. doi: 10.1038/nature13019.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24622199" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Benzoates/chemistry/radiation effects ; Carboxylic Acids/chemistry ; Catalysis ; Infrared Rays ; Models, Chemical ; Models, Molecular ; Molecular Conformation ; Peptides/chemistry ; Phenols/chemistry ; Structure-Activity Relationship ; Thermodynamics ; *Vibration
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    Spontaneous transfer of chirality in an atropisomerically enriched two-axis system (2014)
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    Publication Date: 2014-04-22
    Description: One of the most well-recognized stereogenic elements in a chiral molecule is an sp(3)-hybridized carbon atom that is connected to four different substituents. Axes of chirality can also exist about bonds with hindered barriers of rotation; molecules containing such axes are known as atropisomers. Understanding the dynamics of these systems can be useful, for example, in the design of single-atropisomer drugs or molecular switches and motors. For molecules that exhibit a single axis of chirality, rotation about that axis leads to racemization as the system reaches equilibrium. Here we report a two-axis system for which an enantioselective reaction produces four stereoisomers (two enantiomeric pairs): following a catalytic asymmetric transformation, we observe a kinetically controlled product distribution that is perturbed from the system's equilibrium position. As the system undergoes isomerization, one of the diastereomeric pairs drifts spontaneously to a higher enantiomeric ratio. In a compensatory manner, the enantiomeric ratio of the other diastereomeric pair decreases. These observations are made for a class of unsymmetrical amides that exhibits two asymmetric axes--one axis is defined through a benzamide substructure, and the other axis is associated with differentially N,N-disubstituted amides. The stereodynamics of these substrates provides an opportunity to observe a curious interplay of kinetics and thermodynamics intrinsic to a system of stereoisomers that is constrained to a situation of partial equilibrium.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008667/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008667/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barrett, Kimberly T -- Metrano, Anthony J -- Rablen, Paul R -- Miller, Scott J -- GM-068649/GM/NIGMS NIH HHS/ -- R37 GM068649/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 May 1;509(7498):71-5. doi: 10.1038/nature13189. Epub 2014 Apr 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Yale University, PO Box 208107, New Haven, Connecticut 06520-8107, USA. ; Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania 19081-1397, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24747399" target="_blank"〉PubMed〈/a〉
    Keywords: Benzamides/chemical synthesis/*chemistry ; Bromine/chemistry ; Carbon/chemistry ; Catalysis ; Kinetics ; Molecular Structure ; Pharmaceutical Preparations/chemistry ; Rotation ; Stereoisomerism ; Thermodynamics
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    Catalysts from synthetic genetic polymers (2014)
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    Publication Date: 2014-12-04
    Description: The emergence of catalysis in early genetic polymers such as RNA is considered a key transition in the origin of life, pre-dating the appearance of protein enzymes. DNA also demonstrates the capacity to fold into three-dimensional structures and form catalysts in vitro. However, to what degree these natural biopolymers comprise functionally privileged chemical scaffolds for folding or the evolution of catalysis is not known. The ability of synthetic genetic polymers (XNAs) with alternative backbone chemistries not found in nature to fold into defined structures and bind ligands raises the possibility that these too might be capable of forming catalysts (XNAzymes). Here we report the discovery of such XNAzymes, elaborated in four different chemistries (arabino nucleic acids, ANA; 2'-fluoroarabino nucleic acids, FANA; hexitol nucleic acids, HNA; and cyclohexene nucleic acids, CeNA) directly from random XNA oligomer pools, exhibiting in trans RNA endonuclease and ligase activities. We also describe an XNA-XNA ligase metalloenzyme in the FANA framework, establishing catalysis in an entirely synthetic system and enabling the synthesis of FANA oligomers and an active RNA endonuclease FANAzyme from its constituent parts. These results extend catalysis beyond biopolymers and establish technologies for the discovery of catalysts in a wide range of polymer scaffolds not found in nature. Evolution of catalysis independent of any natural polymer has implications for the definition of chemical boundary conditions for the emergence of life on Earth and elsewhere in the Universe.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336857/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336857/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Taylor, Alexander I -- Pinheiro, Vitor B -- Smola, Matthew J -- Morgunov, Alexey S -- Peak-Chew, Sew -- Cozens, Christopher -- Weeks, Kevin M -- Herdewijn, Piet -- Holliger, Philipp -- MC_U105178804/Medical Research Council/United Kingdom -- MC_U105185859/Medical Research Council/United Kingdom -- T32 GM008570/GM/NIGMS NIH HHS/ -- U105178804/Medical Research Council/United Kingdom -- Biotechnology and Biological Sciences Research Council/United Kingdom -- England -- Nature. 2015 Feb 19;518(7539):427-30. doi: 10.1038/nature13982. Epub 2014 Dec 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK. ; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA. ; 1] KU Leuven, Rega Institute, Minderbroedersstraat 10, B 3000 Leuven, Belgium [2] Universite Evry, Institute of Systems and Synthetic Biology, 5 rue Henri Desbrueres, 91030 Evry Cedex, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25470036" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Catalysis ; Endonucleases/metabolism ; Ligases/metabolism ; Nucleic Acids/*chemical synthesis/chemistry/*metabolism ; Polymers/*chemical synthesis/*chemistry/metabolism ; RNA/metabolism
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    RNA catalyses nuclear pre-mRNA splicing (2013)
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    Publication Date: 2013-11-08
    Description: In nuclear pre-messenger RNA splicing, introns are excised by the spliceosome, a dynamic machine composed of both proteins and small nuclear RNAs (snRNAs). Over thirty years ago, after the discovery of self-splicing group II intron RNAs, the snRNAs were proposed to catalyse splicing. However, no definitive evidence for a role of either RNA or protein in catalysis by the spliceosome has been reported so far. By using metal rescue strategies in spliceosomes from budding yeast, here we show that the U6 snRNA catalyses both of the two splicing reactions by positioning divalent metals that stabilize the leaving groups during each reaction. Notably, all of the U6 catalytic metal ligands we identified correspond to the ligands observed to position catalytic, divalent metals in crystal structures of a group II intron RNA. These findings indicate that group II introns and the spliceosome share common catalytic mechanisms and probably common evolutionary origins. Our results demonstrate that RNA mediates catalysis within the spliceosome.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666680/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666680/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fica, Sebastian M -- Tuttle, Nicole -- Novak, Thaddeus -- Li, Nan-Sheng -- Lu, Jun -- Koodathingal, Prakash -- Dai, Qing -- Staley, Jonathan P -- Piccirilli, Joseph A -- 5T32GM008720/GM/NIGMS NIH HHS/ -- R01 GM088656/GM/NIGMS NIH HHS/ -- R01GM088656/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 Nov 14;503(7475):229-34. doi: 10.1038/nature12734. Epub 2013 Nov 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Graduate Program in Cell and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA [2] Department of Molecular Genetics and Cell Biology, Cummings Life Sciences Center, 920 East 58th Street, The University of Chicago, Chicago, Illinois 60637, USA [3].〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24196718" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Cell Nucleus/metabolism ; Introns/genetics ; Metals/metabolism ; Models, Biological ; RNA Precursors/*metabolism ; *RNA Splicing ; RNA, Fungal/metabolism ; RNA, Small Nuclear/*metabolism ; Saccharomyces cerevisiae/*genetics/*metabolism ; Spliceosomes/metabolism
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    Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism (2013)
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    Publication Date: 2013-07-13
    Description: Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Bronsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated Csp3-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yuan, Changxia -- Liang, Yong -- Hernandez, Taylor -- Berriochoa, Adrian -- Houk, Kendall N -- Siegel, Dionicio -- England -- Nature. 2013 Jul 11;499(7457):192-6. doi: 10.1038/nature12284.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23846658" target="_blank"〉PubMed〈/a〉
    Keywords: Benzene Derivatives/chemistry ; Carbon/*chemistry ; Catalysis ; Diterpenes, Abietane/chemistry ; Hydrogen/*chemistry ; Hydrogen Bonding ; Hydrolysis ; Hydroxylation ; Metals ; Oxidants/chemistry ; Oxidation-Reduction ; Oxygen/chemistry ; Peroxides/chemistry ; Phenols/chemistry ; Quantum Theory ; Sesquiterpenes/chemistry ; Tocopherols/chemistry
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    Q&A: The bond shifter. Interview by Rebecca Melen (2013)
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    Details
    Publication Date: 2013-10-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grubbs, Robert -- England -- Nature. 2013 Oct 17;502(7471):S56-7. doi: 10.1038/502S56a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24132334" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Catalysis ; *Chemistry/education/history ; History, 20th Century ; History, 21st Century ; Industry/economics ; Nobel Prize ; Organometallic Compounds/chemistry ; Research Support as Topic ; Ruthenium/chemistry
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    Gold (2013)
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    Publication Date: 2013-03-15
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brody, Herb -- England -- Nature. 2013 Mar 14;495(7440):S1. doi: 10.1038/495S1a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23486094" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteria/metabolism ; Catalysis ; Drug Delivery Systems ; Electronics/instrumentation ; *Gold/chemistry/economics/history/isolation & purification ; History, Ancient ; Metal Nanoparticles/administration & dosage/microbiology ; Solar Energy
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    Catalytic conversion of nitrogen to ammonia by an iron model complex (2013)
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    Publication Date: 2013-09-06
    Description: The reduction of nitrogen (N2) to ammonia (NH3) is a requisite transformation for life. Although it is widely appreciated that the iron-rich cofactors of nitrogenase enzymes facilitate this transformation, how they do so remains poorly understood. A central element of debate has been the exact site or sites of N2 coordination and reduction. In synthetic inorganic chemistry, an early emphasis was placed on molybdenum because it was thought to be an essential element of nitrogenases and because it had been established that well-defined molybdenum model complexes could mediate the stoichiometric conversion of N2 to NH3 (ref. 9). This chemical transformation can be performed in a catalytic fashion by two well-defined molecular systems that feature molybdenum centres. However, it is now thought that iron is the only transition metal essential to all nitrogenases, and recent biochemical and spectroscopic data have implicated iron instead of molybdenum as the site of N2 binding in the FeMo-cofactor. Here we describe a tris(phosphine)borane-supported iron complex that catalyses the reduction of N2 to NH3 under mild conditions, and in which more than 40 per cent of the proton and reducing equivalents are delivered to N2. Our results indicate that a single iron site may be capable of stabilizing the various NxHy intermediates generated during catalytic NH3 formation. Geometric tunability at iron imparted by a flexible iron-boron interaction in our model system seems to be important for efficient catalysis. We propose that the interstitial carbon atom recently assigned in the nitrogenase cofactor may have a similar role, perhaps by enabling a single iron site to mediate the enzymatic catalysis through a flexible iron-carbon interaction.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3882122/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3882122/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Anderson, John S -- Rittle, Jonathan -- Peters, Jonas C -- GM 070757/GM/NIGMS NIH HHS/ -- R01 GM070757/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 Sep 5;501(7465):84-7. doi: 10.1038/nature12435.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24005414" target="_blank"〉PubMed〈/a〉
    Keywords: Ammonia/*chemical synthesis/chemistry ; Biomimetics ; Boranes/chemistry ; Catalysis ; Iron/*chemistry ; Molybdenum/chemistry/metabolism ; Molybdoferredoxin/chemistry/metabolism ; Nitrogen/*chemistry ; *Nitrogen Fixation ; Nitrogenase/chemistry/metabolism ; Oxidation-Reduction ; Phosphines/chemistry
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    Stereoinversion of tertiary alcohols to tertiary-alkyl isonitriles and amines (2013)
    Nature Publishing Group (NPG)
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    Publication Date: 2013-09-13
    Description: The SN2 reaction (bimolecular nucleophilic substitution) is a well-known chemical transformation that can be used to join two smaller molecules together into a larger molecule or to exchange one functional group for another. The SN2 reaction proceeds in a very predictable manner: substitution occurs with inversion of stereochemistry, resulting from the 'backside attack' of the electrophilic carbon by the nucleophile. A significant limitation of the SN2 reaction is its intolerance for tertiary carbon atoms: whereas primary and secondary alcohols are viable precursor substrates, tertiary alcohols and their derivatives usually either fail to react or produce stereochemical mixtures of products. Here we report the stereochemical inversion of chiral tertiary alcohols with a nitrogenous nucleophile facilitated by a Lewis-acid-catalysed solvolysis. The method is chemoselective against secondary and primary alcohols, thereby complementing the selectivity of the SN2 reaction. Furthermore, this method for carbon-nitrogen bond formation mimics a putative biosynthetic step in the synthesis of marine terpenoids and enables their preparation from the corresponding terrestrial terpenes. We expect that the general attributes of the methodology will allow chiral tertiary alcohols to be considered viable substrates for stereoinversion reactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pronin, Sergey V -- Reiher, Christopher A -- Shenvi, Ryan A -- England -- Nature. 2013 Sep 12;501(7466):195-9. doi: 10.1038/nature12472.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24025839" target="_blank"〉PubMed〈/a〉
    Keywords: Alcohols/*chemistry ; Amines/*chemical synthesis/chemistry ; Aquatic Organisms/chemistry ; Carbon/chemistry ; Catalysis ; Chemistry Techniques, Synthetic/*methods ; Cyanides/chemistry ; Lewis Acids/chemistry ; Molecular Structure ; Nitriles/*chemical synthesis/*chemistry ; Nitrogen/chemistry ; Stereoisomerism ; Terpenes/chemical synthesis/chemistry
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    Vinylogous chain branching catalysed by a dedicated polyketide synthase module (2013)
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    Publication Date: 2013-09-21
    Description: Bacteria use modular polyketide synthases (PKSs) to assemble complex polyketides, many of which are leads for the development of clinical drugs, in particular anti-infectives and anti-tumoral agents. Because these multifarious compounds are notoriously difficult to synthesize, they are usually produced by microbial fermentation. During the past two decades, an impressive body of knowledge on modular PKSs has been gathered that not only provides detailed insight into the biosynthetic pathways but also allows the rational engineering of enzymatic processing lines to yield structural analogues. Notably, a hallmark of all PKS modules studied so far is the head-to-tail fusion of acyl and malonyl building blocks, which leads to linear backbones. Yet, structural diversity is limited by this uniform assembly mode. Here we demonstrate a new type of PKS module from the endofungal bacterium Burkholderia rhizoxinica that catalyses a Michael-type acetyl addition to generate a branch in the carbon chain. In vitro reconstitution of the entire PKS module, X-ray structures of a ketosynthase-branching didomain and mutagenesis experiments revealed a crucial role of the ketosynthase domain in branching the carbon chain. We present a trapped intermediary state in which acyl carrier protein and ketosynthase are covalently linked by the branched polyketide and suggest a new mechanism for chain alkylation, which is functionally distinct from terpenoid-like beta-branching. For the rice seedling blight toxin rhizoxin, one of the strongest known anti-mitotic agents, the non-canonical polyketide modification is indispensable for phytotoxic and anti-tumoral activities. We propose that the formation of related pharmacophoric groups follows the same general scheme and infer a unifying vinylogous branching reaction for PKS modules with a ketosynthase-branching-acyl-carrier-protein architecture. This study unveils the structure and function of a new PKS module that broadens the biosynthetic scope of polyketide biosynthesis and sets the stage for rationally creating structural diversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bretschneider, Tom -- Heim, Joel B -- Heine, Daniel -- Winkler, Robert -- Busch, Benjamin -- Kusebauch, Bjorn -- Stehle, Thilo -- Zocher, Georg -- Hertweck, Christian -- England -- Nature. 2013 Oct 3;502(7469):124-8. doi: 10.1038/nature12588. Epub 2013 Sep 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena 07745, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24048471" target="_blank"〉PubMed〈/a〉
    Keywords: Burkholderia/chemistry/*enzymology/genetics ; Catalysis ; Crystallography, X-Ray ; Lactones/metabolism ; Macrolides/chemistry ; *Models, Molecular ; Mutagenesis ; Polyketide Synthases/genetics/*metabolism ; Protein Structure, Tertiary
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    Q&A: A sustainable chemist. Interview by Jonathan Moerdyk (2013)
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    Publication Date: 2013-10-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schrock, Richard -- England -- Nature. 2013 Oct 17;502(7471):S59. doi: 10.1038/502S59a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24132336" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/*chemistry ; Catalysis ; *Chemistry/trends ; Computer Simulation ; Green Chemistry Technology/trends ; Metals/chemistry ; Nobel Prize
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    The nitrogen fix (2013)
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    Publication Date: 2013-09-07
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉England -- Nature. 2013 Sep 5;501(7465):6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24010143" target="_blank"〉PubMed〈/a〉
    Keywords: Ammonia/*chemical synthesis ; Catalysis ; Fertilizers/history/supply & distribution ; History, 19th Century ; History, 20th Century ; History, 21st Century ; Hydrogen/chemistry ; Iron/*chemistry ; Nitrogen/chemistry ; *Nitrogen Fixation ; Nobel Prize
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    Catalysis: The accelerator (2013)
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    Publication Date: 2013-03-15
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Peplow, Mark -- England -- Nature. 2013 Mar 14;495(7440):S10-1. doi: 10.1038/495S10a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23486095" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylene/chemistry ; Automobiles ; Carbon Dioxide/chemistry ; Carbon Monoxide/chemistry ; Catalysis ; Gold/*chemistry/economics ; Humans ; Humidity ; Metal Nanoparticles/chemistry ; Particle Size ; Platinum/chemistry/economics ; Respiratory Protective Devices ; Vinyl Chloride/chemical synthesis/chemistry
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    Simple organic molecules as catalysts for enantioselective synthesis of amines and alcohols (2013)
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    Publication Date: 2013-02-15
    Description: The discovery of catalysts that can be used to synthesize complex organic compounds by enantioselective transformations is central to advances in the life sciences; for this reason, many chemists aim to discover catalysts that allow for preparation of chiral molecules as predominantly one mirror-image isomer. The ideal catalyst should not contain precious elements and should bring reactions to completion in a few hours through operationally simple procedures. Here we introduce a set of small organic molecules that can catalyse reactions of unsaturated organoboron reagents with imines and carbonyls; the products of the reactions are enantiomerically pure amines and alcohols, which might serve as intermediates in the preparation of biologically active molecules. A distinguishing feature of this catalyst class is the presence of a 'key' proton embedded within their structure. Catalysts are derived from the abundant amino acid valine and are prepared in large quantities in four steps with inexpensive reagents. Reactions are scalable, do not demand stringent conditions, and can be performed with as little as 0.25 mole per cent catalyst in less than six hours at room temperature to generate products in more than 85 per cent yield and 〉/=97:3 enantiomeric ratio. The efficiency, selectivity and operational simplicity of the transformations and the range of boron-based reagents are expected to render this advance important for future progress in syntheses of amines and alcohols, which are useful in chemistry, biology and medicine.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3576146/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3576146/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Silverio, Daniel L -- Torker, Sebastian -- Pilyugina, Tatiana -- Vieira, Erika M -- Snapper, Marc L -- Haeffner, Fredrik -- Hoveyda, Amir H -- GM-57212/GM/NIGMS NIH HHS/ -- R01 GM057212/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 Feb 14;494(7436):216-21. doi: 10.1038/nature11844.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23407537" target="_blank"〉PubMed〈/a〉
    Keywords: Alcohols/*chemical synthesis/chemistry ; Amines/*chemical synthesis/chemistry ; Boron/chemistry ; Catalysis ; Imines/chemistry ; Indicators and Reagents ; Molecular Structure ; Protons ; Stereoisomerism ; Temperature ; Time Factors ; Valine/*analogs & derivatives/*chemistry
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    High-valent organometallic copper and palladium in catalysis (2012)
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    Publication Date: 2012-04-14
    Description: Copper and palladium catalysts are critically important in numerous commercial chemical processes. Improvements in the activity, selectivity and scope of these catalysts could drastically reduce the environmental impact, and increase the sustainability, of chemical reactions. One rapidly developing strategy for achieving these goals is to use 'high-valent' organometallic copper and palladium intermediates in catalysis. Here we describe recent advances involving both the fundamental chemistry and the applications of these high-valent metal complexes in numerous synthetically useful catalytic transformations.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384170/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384170/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hickman, Amanda J -- Sanford, Melanie S -- GM073836/GM/NIGMS NIH HHS/ -- R01 GM073836/GM/NIGMS NIH HHS/ -- England -- Nature. 2012 Apr 11;484(7393):177-85. doi: 10.1038/nature11008.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22498623" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Copper/*chemistry ; Drug Industry ; Green Chemistry Technology ; Organometallic Compounds/*chemistry ; Palladium/*chemistry
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    Stereocontrolled organocatalytic synthesis of prostaglandin PGF2alpha in seven steps (2012)
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    Publication Date: 2012-08-17
    Description: Prostaglandins are hormone-like chemical messengers that regulate a broad range of physiological activities, including blood circulation, digestion and reproduction. Their biological activities and their complex molecular architectures have made prostaglandins popular targets for synthetic organic chemists for over 40 years. Prostaglandin analogues are widely used as pharmaceuticals and some, such as latanoprost, which is used to treat glaucoma, have become billion-dollar drugs. Previously reported syntheses of these compounds are quite lengthy, and every chemical step costs time and energy, generates waste and is accompanied by material losses. Using a new bond disconnection, here we report a concise synthesis of the most complex prostaglandin, PGF2alpha, with high levels of control of relative and absolute stereochemistry, and fewer steps. The key step is an aldol cascade reaction of succinaldehyde using proline organocatalysis to create a bicyclic enal in one step and an enantiomeric excess of 98%. This intermediate bicyclic enal is fully primed with the appropriate functionality for attachment of the remaining groups. Access to this bicyclic enal will not only render existing prostaglandin-based drugs more affordable, but will also facilitate the rapid exploration of related chemical structures around the ubiquitous five-membered ring motif, such as potentially therapeutic prostaglandin analogues.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Coulthard, Graeme -- Erb, William -- Aggarwal, Varinder K -- 246785/European Research Council/International -- England -- Nature. 2012 Sep 13;489(7415):278-81. doi: 10.1038/nature11411.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22895192" target="_blank"〉PubMed〈/a〉
    Keywords: Aldehydes/chemistry ; Catalysis ; Chemistry Techniques, Synthetic/economics/*methods ; Dinoprost/*chemical synthesis/*chemistry ; Molecular Structure ; Proline/chemistry ; Prostaglandins F, Synthetic/*chemical synthesis/*chemistry ; Stereoisomerism
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    Integration of chemical catalysis with extractive fermentation to produce fuels (2012)
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    Publication Date: 2012-11-09
    Description: Nearly one hundred years ago, the fermentative production of acetone by Clostridium acetobutylicum provided a crucial alternative source of this solvent for manufacture of the explosive cordite. Today there is a resurgence of interest in solventogenic Clostridium species to produce n-butanol and ethanol for use as renewable alternative transportation fuels. Acetone, a product of acetone-n-butanol-ethanol (ABE) fermentation, harbours a nucleophilic alpha-carbon, which is amenable to C-C bond formation with the electrophilic alcohols produced in ABE fermentation. This functionality can be used to form higher-molecular-mass hydrocarbons similar to those found in current jet and diesel fuels. Here we describe the integration of biological and chemocatalytic routes to convert ABE fermentation products efficiently into ketones by a palladium-catalysed alkylation. Tuning of the reaction conditions permits the production of either petrol or jet and diesel precursors. Glyceryl tributyrate was used for the in situ selective extraction of both acetone and alcohols to enable the simple integration of ABE fermentation and chemical catalysis, while reducing the energy demand of the overall process. This process provides a means to selectively produce petrol, jet and diesel blend stocks from lignocellulosic and cane sugars at yields near their theoretical maxima.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Anbarasan, Pazhamalai -- Baer, Zachary C -- Sreekumar, Sanil -- Gross, Elad -- Binder, Joseph B -- Blanch, Harvey W -- Clark, Douglas S -- Toste, F Dean -- England -- Nature. 2012 Nov 8;491(7423):235-9. doi: 10.1038/nature11594.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23135469" target="_blank"〉PubMed〈/a〉
    Keywords: 1-Butanol/metabolism ; Acetone/metabolism ; Alkylation ; *Biofuels ; Biomass ; Catalysis ; Clostridium acetobutylicum/*metabolism ; Ethanol/metabolism ; *Fermentation ; *Gasoline ; Ketones/chemistry/metabolism ; Lignin/chemistry/metabolism ; Models, Chemical ; Palladium/*chemistry ; Saccharum/chemistry ; Time Factors ; Triglycerides/chemistry
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    Adenylylation control by intra- or intermolecular active-site obstruction in Fic proteins (2012)
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    Publication Date: 2012-01-24
    Description: Fic proteins that are defined by the ubiquitous FIC (filamentation induced by cyclic AMP) domain are known to catalyse adenylylation (also called AMPylation); that is, the transfer of AMP onto a target protein. In mammalian cells, adenylylation of small GTPases through Fic proteins injected by pathogenic bacteria can cause collapse of the actin cytoskeleton and cell death. It is unknown how this potentially deleterious adenylylation activity is regulated in the widespread Fic proteins that are found in all domains of life and that are thought to have critical roles in intrinsic signalling processes. Here we show that FIC-domain-mediated adenylylation is controlled by a conserved mechanism of ATP-binding-site obstruction that involves an inhibitory alpha-helix (alpha(inh)) with a conserved (S/T)XXXE(G/N) motif, and that in this mechanism the invariable glutamate competes with ATP gamma-phosphate binding. Consistent with this, FIC-domain-mediated growth arrest of bacteria by the VbhT toxin of Bartonella schoenbuchensis is intermolecularly repressed by the VbhA antitoxin through tight binding of its alpha(inh) to the FIC domain of VbhT, as shown by structure and function analysis. Furthermore, structural comparisons with other bacterial Fic proteins, such as Fic of Neisseria meningitidis and of Shewanella oneidensis, show that alpha(inh) frequently constitutes an amino-terminal or carboxy-terminal extension to the FIC domain, respectively, partially obstructing the ATP binding site in an intramolecular manner. After mutation of the inhibitory motif in various Fic proteins, including the human homologue FICD (also known as HYPE), adenylylation activity is considerably boosted, consistent with the anticipated relief of inhibition. Structural homology modelling of all annotated Fic proteins indicates that inhibition by alpha(inh) is universal and conserved through evolution, as the inhibitory motif is present in approximately 90% of all putatively adenylylation-active FIC domains, including examples from all domains of life and from viruses. Future studies should reveal how intrinsic or extrinsic factors modulate adenylylation activity by weakening the interaction of alpha(inh) with the FIC active site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Engel, Philipp -- Goepfert, Arnaud -- Stanger, Frederic V -- Harms, Alexander -- Schmidt, Alexander -- Schirmer, Tilman -- Dehio, Christoph -- England -- Nature. 2012 Jan 22;482(7383):107-10. doi: 10.1038/nature10729.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22266942" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Amino Acid Sequence ; Bacterial Proteins/*chemistry/*metabolism ; Bartonella ; Carrier Proteins/chemistry/metabolism ; Catalysis ; Catalytic Domain ; Cyclic AMP/*metabolism ; Escherichia coli ; Escherichia coli Proteins/chemistry/metabolism ; Glutamic Acid/metabolism ; Humans ; Membrane Proteins/chemistry/metabolism ; Microbial Viability ; Models, Molecular ; Molecular Weight ; Neisseria meningitidis ; Protein Structure, Tertiary ; Shewanella
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    Asymmetric spiroacetalization catalysed by confined Bronsted acids (2012)
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    Publication Date: 2012-03-17
    Description: Acetals are molecular substructures that contain two oxygen-carbon single bonds at the same carbon atom, and are used in cells to construct carbohydrates and numerous other molecules. A distinctive subgroup are spiroacetals, acetals joining two rings, which occur in a broad range of biologically active compounds, including small insect pheromones and more complex macrocycles. Despite numerous methods for the catalytic asymmetric formation of other commonly occurring stereocentres, there are few approaches that exclusively target the chiral acetal centre and none for spiroacetals. Here we report the design and synthesis of confined Bronsted acids based on a C(2)-symmetric imidodiphosphoric acid motif, enabling a catalytic enantioselective spiroacetalization reaction. These rationally constructed Bronsted acids possess an extremely sterically demanding chiral microenvironment, with a single catalytically relevant and geometrically constrained bifunctional active site. Our catalyst design is expected to be of broad utility in catalytic asymmetric reactions involving small and structurally or functionally unbiased substrates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Coric, Ilija -- List, Benjamin -- England -- Nature. 2012 Mar 14;483(7389):315-9. doi: 10.1038/nature10932.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mulheim an der Ruhr, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22422266" target="_blank"〉PubMed〈/a〉
    Keywords: Acetals/*chemical synthesis/*chemistry ; Animals ; Biological Products/*chemical synthesis/*chemistry/pharmacology ; Catalysis ; Catalytic Domain ; Female ; Male ; Models, Molecular ; Molecular Conformation ; Phosphoric Acids/*chemistry ; Sex Attractants/chemical synthesis/chemistry/pharmacology ; Stereoisomerism ; Thermodynamics
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    Watching DNA polymerase eta make a phosphodiester bond (2012)
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    Publication Date: 2012-07-13
    Description: DNA synthesis has been extensively studied, but the chemical reaction itself has not been visualized. Here we follow the course of phosphodiester bond formation using time-resolved X-ray crystallography. Native human DNA polymerase eta, DNA and dATP were co-crystallized at pH 6.0 without Mg(2+). The polymerization reaction was initiated by exposing crystals to 1 mM Mg(2+) at pH 7.0, and stopped by freezing at desired time points for structural analysis. The substrates and two Mg(2+) ions are aligned within 40 s, but the bond formation is not evident until 80 s. From 80 to 300 s structures show a mixture of decreasing substrate and increasing product of the nucleotidyl-transfer reaction. Transient electron densities indicate that deprotonation and an accompanying C2'-endo to C3'-endo conversion of the nucleophile 3'-OH are rate limiting. A third Mg(2+) ion, which arrives with the new bond and stabilizes the intermediate state, may be an unappreciated feature of the two-metal-ion mechanism.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397672/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397672/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nakamura, Teruya -- Zhao, Ye -- Yamagata, Yuriko -- Hua, Yue-jin -- Yang, Wei -- Z01 DK036146-01/Intramural NIH HHS/ -- England -- Nature. 2012 Jul 11;487(7406):196-201. doi: 10.1038/nature11181.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22785315" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; DNA-Directed DNA Polymerase/chemistry/*metabolism ; Humans ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Magnesium/chemistry ; Metals/chemistry ; *Models, Molecular ; Nucleic Acid Conformation ; Water/chemistry
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    Amino acid provides shortcut to drugs (2012)
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    Publication Date: 2012-08-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanderson, Katharine -- England -- Nature. 2012 Aug 16;488(7411):266. doi: 10.1038/488266a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22895313" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; *Chemistry Techniques, Synthetic ; Neuroprotective Agents/chemical synthesis/chemistry ; Pharmaceutical Preparations/*chemical synthesis/*chemistry ; Proline/*chemistry ; Prostaglandins F, Synthetic/*chemical synthesis/*chemistry
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    Structured spheres generated by an in-fibre fluid instability (2012)
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    Publication Date: 2012-07-20
    Description: From drug delivery to chemical and biological catalysis and cosmetics, the need for efficient fabrication pathways for particles over a wide range of sizes, from a variety of materials, and in many different structures has been well established. Here we harness the inherent scalability of fibre production and an in-fibre Plateau-Rayleigh capillary instability for the fabrication of uniformly sized, structured spherical particles spanning an exceptionally wide range of sizes: from 2 mm down to 20 nm. Thermal processing of a multimaterial fibre controllably induces the instability, resulting in a well-ordered, oriented emulsion in three dimensions. The fibre core and cladding correspond to the dispersed and continuous phases, respectively, and are both frozen in situ on cooling, after which the particles are released when needed. By arranging a variety of structures and materials in a macroscopic scaled-up model of the fibre, we produce composite, structured, spherical particles, such as core-shell particles, two-compartment 'Janus' particles, and multi-sectioned 'beach ball' particles. Moreover, producing fibres with a high density of cores allows for an unprecedented level of parallelization. In principle, 10(8) 50-nm cores may be embedded in metres-long, 1-mm-diameter fibre, which can be induced to break up simultaneously throughout its length, into uniformly sized, structured spheres.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaufman, Joshua J -- Tao, Guangming -- Shabahang, Soroush -- Banaei, Esmaeil-Hooman -- Deng, Daosheng S -- Liang, Xiangdong -- Johnson, Steven G -- Fink, Yoel -- Abouraddy, Ayman F -- England -- Nature. 2012 Jul 26;487(7408):463-7. doi: 10.1038/nature11215.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida 32816, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22810590" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chemistry Techniques, Synthetic/*methods ; Delayed-Action Preparations ; Emulsions/chemistry ; Glass/chemistry ; *Microspheres ; Nanostructures/*chemistry/ultrastructure ; Particle Size ; Polymers/chemistry ; Temperature
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    Catalytic functionalization of unactivated primary C-H bonds directed by an alcohol (2012)
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    Publication Date: 2012-03-03
    Description: New synthetic methods for the catalytic functionalization of C-H bonds have the potential to revolutionize the synthesis of complex molecules. However, the realization of this synthetic potential requires the ability to functionalize selectively one C-H bond in a compound containing many such bonds and an array of functional groups. The site-selective functionalization of aliphatic C-H bonds is one of the greatest challenges that must be met for C-H bond functionalization to be used widely in complex-molecule synthesis, and processes catalysed by transition-metals provide the opportunity to control selectivity. Current methods for catalytic, aliphatic C-H bond functionalization typically rely on the presence of one inherently reactive C-H bond, or on installation and subsequent removal of directing groups that are not components of the desired molecule. To overcome these limitations, we sought catalysts and reagents that would facilitate aliphatic C-H bond functionalization at a single site, with chemoselectivity derived from the properties of the catalyst and site-selectivity directed by common functional groups contained in both the reactant and the desired product. Here we show that the combination of an iridium-phenanthroline catalyst and a dihydridosilane reagent leads to the site-selective gamma-functionalization of primary C-H bonds controlled by a hydroxyl group, the most common functional group in natural products. The scope of the reaction encompasses alcohols and ketones bearing many substitution patterns and auxiliary functional groups; this broad scope suggests that this methodology will be suitable for the site-selective and diastereoselective functionalization of complex natural products.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Simmons, Eric M -- Hartwig, John F -- GM087901/GM/NIGMS NIH HHS/ -- England -- Nature. 2012 Feb 29;483(7387):70-3. doi: 10.1038/nature10785.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22382981" target="_blank"〉PubMed〈/a〉
    Keywords: Alcohols/*chemistry ; Alkadienes/chemistry ; Biological Products/chemistry ; Carbon/*chemistry ; Catalysis ; Hydrogen/*chemistry ; Indicators and Reagents/chemistry ; Iridium/chemistry ; Ketones/chemistry ; Ligands ; Norbornanes/chemistry ; Oxygen/chemistry ; Phenanthrolines/chemistry ; Pyridines/chemistry
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    Synthesis of macrocyclic natural products by catalyst-controlled stereoselective ring-closing metathesis (2011)
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    Publication Date: 2011-11-05
    Description: Many natural products contain a C = C double bond through which various other derivatives can be prepared; the stereochemical identity of the alkene can be critical to the biological activities of such molecules. Catalytic ring-closing metathesis (RCM) is a widely used method for the synthesis of large unsaturated rings; however, cyclizations often proceed without control of alkene stereochemistry. This shortcoming is particularly costly when the cyclization reaction is performed after a long sequence of other chemical transformations. Here we outline a reliable, practical and general approach for the efficient and highly stereoselective synthesis of macrocyclic alkenes by catalytic RCM; transformations deliver up to 97% of the Z isomer owing to control induced by a tungsten-based alkylidene. Utility is demonstrated through the stereoselective preparation of epothilone C (refs 3-5) and nakadomarin A (ref. 6), the previously reported syntheses of which have been marred by late-stage, non-selective RCM. The tungsten alkylidene can be manipulated in air, delivering the products in useful yields with high stereoselectivity. As a result of efficient RCM and re-incorporation of side products into the catalytic cycle with minimal alkene isomerization, desired cyclizations proceed in preference to alternative pathways, even under relatively high substrate concentration.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3211109/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3211109/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yu, Miao -- Wang, Chenbo -- Kyle, Andrew F -- Jakubec, Pavol -- Dixon, Darren J -- Schrock, Richard R -- Hoveyda, Amir H -- GM-59426/GM/NIGMS NIH HHS/ -- R01 GM059426/GM/NIGMS NIH HHS/ -- R01 GM059426-12/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 Nov 2;479(7371):88-93. doi: 10.1038/nature10563.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22051677" target="_blank"〉PubMed〈/a〉
    Keywords: Alkanes/chemistry ; Alkenes/chemistry ; Biological Products/*chemical synthesis/chemistry ; Carbolines/chemical synthesis/chemistry ; Catalysis ; Chemistry Techniques, Synthetic/*methods ; Cyclization ; Epothilones/chemical synthesis/chemistry ; Stereoisomerism
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    Catalysis for fluorination and trifluoromethylation (2011)
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    Publication Date: 2011-05-27
    Description: Recent advances in catalysis have made the incorporation of fluorine into complex organic molecules easier than ever before, but selective, general and practical fluorination reactions remain sought after. Fluorination of molecules often imparts desirable properties, such as metabolic and thermal stability, and fluorinated molecules are therefore frequently used as pharmaceuticals or materials. But the formation of carbon-fluorine bonds in complex molecules is a significant challenge. Here we discuss reactions to make organofluorides that have emerged within the past few years and which exemplify how to overcome some of the intricate challenges associated with fluorination.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119199/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119199/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Furuya, Takeru -- Kamlet, Adam S -- Ritter, Tobias -- GM088237/GM/NIGMS NIH HHS/ -- R01 GM088237/GM/NIGMS NIH HHS/ -- R01 GM088237-01A1/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 May 26;473(7348):470-7. doi: 10.1038/nature10108.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21614074" target="_blank"〉PubMed〈/a〉
    Keywords: Argon/chemistry ; Carbon/chemistry ; Catalysis ; Fluorine/*chemistry ; *Halogenation ; *Methylation
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    Collective synthesis of natural products by means of organocascade catalysis (2011)
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    Publication Date: 2011-07-15
    Description: Organic chemists are now able to synthesize small quantities of almost any known natural product, given sufficient time, resources and effort. However, translation of the academic successes in total synthesis to the large-scale construction of complex natural products and the development of large collections of biologically relevant molecules present significant challenges to synthetic chemists. Here we show that the application of two nature-inspired techniques, namely organocascade catalysis and collective natural product synthesis, can facilitate the preparation of useful quantities of a range of structurally diverse natural products from a common molecular scaffold. The power of this concept has been demonstrated through the expedient, asymmetric total syntheses of six well-known alkaloid natural products: strychnine, aspidospermidine, vincadifformine, akuammicine, kopsanone and kopsinine.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439143/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439143/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jones, Spencer B -- Simmons, Bryon -- Mastracchio, Anthony -- MacMillan, David W C -- R01 GM078201/GM/NIGMS NIH HHS/ -- R01 GM078201-05/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 Jul 13;475(7355):183-8. doi: 10.1038/nature10232.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21753848" target="_blank"〉PubMed〈/a〉
    Keywords: Alkaloids/*chemical synthesis/chemistry ; Biological Products/*chemical synthesis/chemistry ; Biomimetics ; Catalysis ; Chemistry, Organic/methods ; Cyclization ; Indole Alkaloids/chemical synthesis/chemistry ; Indoles/chemical synthesis/chemistry ; Quinolines/chemical synthesis/chemistry ; Research Design ; Strychnine/chemical synthesis/chemistry
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    Materials chemistry: catalytic accordions (2011)
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    Publication Date: 2011-05-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Giuseppone, Nicolas -- Lutz, Jean-Francois -- England -- Nature. 2011 May 5;473(7345):40-1. doi: 10.1038/473040a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Faculty of Chemistry, University of Strasbourg, UPR22-CNRS, 67034 Strasbourg, France. giuseppone@unistra.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21544141" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Enzymes/chemical synthesis/*chemistry ; Molecular Conformation ; Polymers/chemical synthesis/*chemistry
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    Asymmetric additions to dienes catalysed by a dithiophosphoric acid (2011)
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    Publication Date: 2011-02-11
    Description: Chiral Bronsted acids (proton donors) have been shown to facilitate a broad range of asymmetric chemical transformations under catalytic conditions without requiring additional toxic or expensive metals. Although the catalysts developed thus far are remarkably effective at activating polarized functional groups, it is not clear whether organic Bronsted acids can be used to catalyse highly enantioselective transformations of unactivated carbon-carbon multiple bonds. This deficiency persists despite the fact that racemic acid-catalysed 'Markovnikov' additions to alkenes are well known chemical transformations. Here we show that chiral dithiophosphoric acids can catalyse the intramolecular hydroamination and hydroarylation of dienes and allenes to generate heterocyclic products in exceptional yield and enantiomeric excess. We present a mechanistic hypothesis that involves the addition of the acid catalyst to the diene, followed by nucleophilic displacement of the resulting dithiophosphate intermediate; we also report mass spectroscopic and deuterium labelling studies in support of the proposed mechanism. The catalysts and concepts revealed in this study should prove applicable to other asymmetric functionalizations of unsaturated systems.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104668/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104668/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shapiro, Nathan D -- Rauniyar, Vivek -- Hamilton, Gregory L -- Wu, Jeffrey -- Toste, F Dean -- R01 GM074774/GM/NIGMS NIH HHS/ -- R01 GM074774-04/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 Feb 10;470(7333):245-9. doi: 10.1038/nature09723.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Chemistry, University of California, Berkeley, California 94720, USA [2].〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21307938" target="_blank"〉PubMed〈/a〉
    Keywords: Acids/chemistry ; Alkenes/*chemistry ; Amination ; Catalysis ; Deuterium ; Indoles/chemistry ; Mass Spectrometry ; Models, Chemical ; Phosphates/*chemistry
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    Catalytic Z-selective olefin cross-metathesis for natural product synthesis (2011)
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    Publication Date: 2011-03-25
    Description: Alkenes are found in many biologically active molecules, and there are a large number of chemical transformations in which alkenes act as the reactants or products (or both) of the reaction. Many alkenes exist as either the E or the higher-energy Z stereoisomer. Catalytic procedures for the stereoselective formation of alkenes are valuable, yet methods enabling the synthesis of 1,2-disubstituted Z alkenes are scarce. Here we report catalytic Z-selective cross-metathesis reactions of terminal enol ethers, which have not been reported previously, and of allylic amides, used until now only in E-selective processes. The corresponding disubstituted alkenes are formed in up to 〉98% Z selectivity and 97% yield. These transformations, promoted by catalysts that contain the highly abundant and inexpensive metal molybdenum, are amenable to gram-scale operations. Use of reduced pressure is introduced as a simple and effective strategy for achieving high stereoselectivity. The utility of this method is demonstrated by its use in syntheses of an anti-oxidant plasmalogen phospholipid, found in electrically active tissues and implicated in Alzheimer's disease, and the potent immunostimulant KRN7000.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3082443/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3082443/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meek, Simon J -- O'Brien, Robert V -- Llaveria, Josep -- Schrock, Richard R -- Hoveyda, Amir H -- GM-59426/GM/NIGMS NIH HHS/ -- R01 GM059426/GM/NIGMS NIH HHS/ -- R01 GM059426-12/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 Mar 24;471(7339):461-6. doi: 10.1038/nature09957.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21430774" target="_blank"〉PubMed〈/a〉
    Keywords: Adjuvants, Immunologic/chemical synthesis/chemistry ; Alkenes/*chemical synthesis/*chemistry ; Amides/chemical synthesis/chemistry ; Antioxidants/metabolism ; Biological Products/*chemical synthesis/*chemistry ; Catalysis ; Ethers/chemistry ; Galactosylceramides/chemical synthesis/chemistry ; Molecular Structure ; Molybdenum/chemistry ; Plasmalogens/chemical synthesis/chemistry ; Stereoisomerism
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    Organic chemistry: Overcoming catalytic bias (2011)
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    Publication Date: 2011-03-25
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, Daesung -- England -- Nature. 2011 Mar 24;471(7339):452-3. doi: 10.1038/471452a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21430766" target="_blank"〉PubMed〈/a〉
    Keywords: Adjuvants, Immunologic/chemical synthesis/chemistry ; Alkenes/*chemical synthesis/*chemistry ; Amides/chemical synthesis/chemistry ; Biological Products/*chemical synthesis/*chemistry ; Catalysis ; Ethers/chemical synthesis/chemistry ; Galactosylceramides/chemical synthesis/chemistry ; Isomerism ; Molybdenum/chemistry
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    A molecular molybdenum-oxo catalyst for generating hydrogen from water (2010)
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    Publication Date: 2010-04-30
    Description: A growing awareness of issues related to anthropogenic climate change and an increase in global energy demand have made the search for viable carbon-neutral sources of renewable energy one of the most important challenges in science today. The chemical community is therefore seeking efficient and inexpensive catalysts that can produce large quantities of hydrogen gas from water. Here we identify a molybdenum-oxo complex that can catalytically generate gaseous hydrogen either from water at neutral pH or from sea water. This work shows that high-valency metal-oxo species can be used to create reduction catalysts that are robust and functional in water, a concept that has broad implications for the design of 'green' and sustainable chemistry cycles.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karunadasa, Hemamala I -- Chang, Christopher J -- Long, Jeffrey R -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Apr 29;464(7293):1329-33. doi: 10.1038/nature08969.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20428167" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Conservation of Energy Resources ; Green Chemistry Technology ; Hydrogen/*chemistry/*isolation & purification ; Molybdenum/*chemistry ; Water/*chemistry
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    Iron-catalysed oxidation intermediates captured in a DNA repair dioxygenase (2010)
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    Publication Date: 2010-11-12
    Description: Mononuclear iron-containing oxygenases conduct a diverse variety of oxidation functions in biology, including the oxidative demethylation of methylated nucleic acids and histones. Escherichia coli AlkB is the first such enzyme that was discovered to repair methylated nucleic acids, which are otherwise cytotoxic and/or mutagenic. AlkB human homologues are known to play pivotal roles in various processes. Here we present structural characterization of oxidation intermediates for these demethylases. Using a chemical cross-linking strategy, complexes of AlkB-double stranded DNA (dsDNA) containing 1,N(6)-etheno adenine (epsilonA), N(3)-methyl thymine (3-meT) and N(3)-methyl cytosine (3-meC) are stabilized and crystallized, respectively. Exposing these crystals, grown under anaerobic conditions containing iron(II) and alpha-ketoglutarate (alphaKG), to dioxygen initiates oxidation in crystallo. Glycol (from epsilonA) and hemiaminal (from 3-meT) intermediates are captured; a zwitterionic intermediate (from 3-meC) is also proposed, based on crystallographic observations and computational analysis. The observation of these unprecedented intermediates provides direct support for the oxidative demethylation mechanism for these demethylases. This study also depicts a general mechanistic view of how a methyl group is oxidatively removed from different biological substrates.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058853/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058853/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yi, Chengqi -- Jia, Guifang -- Hou, Guanhua -- Dai, Qing -- Zhang, Wen -- Zheng, Guanqun -- Jian, Xing -- Yang, Cai-Guang -- Cui, Qiang -- He, Chuan -- GM071440/GM/NIGMS NIH HHS/ -- GM084028/GM/NIGMS NIH HHS/ -- R01 GM071440/GM/NIGMS NIH HHS/ -- R01 GM071440-06/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Nov 11;468(7321):330-3. doi: 10.1038/nature09497.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21068844" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Cross-Linking Reagents/chemistry ; Crystallization ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; *DNA Repair ; DNA Repair Enzymes/metabolism ; Dioxygenases/chemistry/*metabolism ; Escherichia coli/*enzymology ; Escherichia coli Proteins/chemistry/*metabolism ; Humans ; Iron/*metabolism ; Ketoglutaric Acids/metabolism ; Methylation ; Mixed Function Oxygenases/chemistry/*metabolism ; Models, Molecular ; Oxidation-Reduction ; Static Electricity ; Substrate Specificity
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    Microfluidics: Exploiting elephants in the room (2010)
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    Publication Date: 2010-04-09
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wootton, Robert C R -- Demello, Andrew J -- England -- Nature. 2010 Apr 8;464(7290):839-40. doi: 10.1038/464839a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20376138" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Catalysis ; Drug Evaluation, Preclinical/instrumentation/methods ; Microfluidic Analytical Techniques/*instrumentation/*methods/standards
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    Origins of life: Systems chemistry on early Earth (2009)
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    Publication Date: 2009-05-16
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Szostak, Jack W -- England -- Nature. 2009 May 14;459(7244):171-2. doi: 10.1038/459171a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19444196" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; *Models, Chemical ; *Origin of Life ; Oxazoles/chemical synthesis/chemistry ; Phosphates/chemistry ; Pyrimidines/*chemical synthesis/chemistry ; Ribonucleotides/*chemical synthesis/chemistry
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    Scaleable catalytic asymmetric Strecker syntheses of unnatural alpha-amino acids (2009)
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    Publication Date: 2009-10-16
    Description: Alpha-amino acids are the building blocks of proteins and are widely used as components of medicinally active molecules and chiral catalysts. Efficient chemo-enzymatic methods for the synthesis of enantioenriched alpha-amino acids have been developed, but it is still a challenge to obtain non-natural amino acids. Alkene hydrogenation is broadly useful for the enantioselective catalytic synthesis of many classes of amino acids, but it is not possible to obtain alpha-amino acids bearing aryl or quaternary alkyl alpha-substituents using this method. The Strecker synthesis-the reaction of an imine or imine equivalent with hydrogen cyanide, followed by nitrile hydrolysis-is an especially versatile chemical method for the synthesis of racemic alpha-amino acids. Asymmetric Strecker syntheses using stoichiometric amounts of a chiral reagent have been applied successfully on gram-to-kilogram scales, yielding enantiomerically enriched alpha-amino acids. In principle, Strecker syntheses employing sub-stoichiometric quantities of a chiral reagent could provide a practical alternative to these approaches, but the reported catalytic asymmetric methods have seen limited use on preparative scales (more than a gram). The limited utility of existing catalytic methods may be due to several important factors, including the relatively complex and precious nature of the catalysts and the requisite use of hazardous cyanide sources. Here we report a new catalytic asymmetric method for the syntheses of highly enantiomerically enriched non-natural amino acids using a simple chiral amido-thiourea catalyst to control the key hydrocyanation step. This catalyst is robust, without sensitive functional groups, so it is compatible with aqueous cyanide salts, which are safer and easier to handle than other cyanide sources; this makes the method adaptable to large-scale synthesis. We have used this new method to obtain enantiopure amino acids that are not readily prepared by enzymatic methods or by chemical hydrogenation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2778849/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2778849/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zuend, Stephan J -- Coughlin, Matthew P -- Lalonde, Mathieu P -- Jacobsen, Eric N -- P50 GM069721/GM/NIGMS NIH HHS/ -- P50 GM069721-070007/GM/NIGMS NIH HHS/ -- P50 GM069721-080007/GM/NIGMS NIH HHS/ -- R37 GM043214/GM/NIGMS NIH HHS/ -- R37 GM043214-17/GM/NIGMS NIH HHS/ -- R37 GM043214-18/GM/NIGMS NIH HHS/ -- R37 GM043214-19/GM/NIGMS NIH HHS/ -- England -- Nature. 2009 Oct 15;461(7266):968-70. doi: 10.1038/nature08484.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard University, Department of Chemistry and Chemical Biology, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19829379" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Hydrogenation ; Imines/chemistry ; Ligands ; Potassium Cyanide/chemistry ; Thiourea/chemistry ; Valine/*analogs & derivatives/chemical synthesis/chemistry
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    Hidden alternative structures of proline isomerase essential for catalysis (2009)
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    Publication Date: 2009-12-04
    Description: A long-standing challenge is to understand at the atomic level how protein dynamics contribute to enzyme catalysis. X-ray crystallography can provide snapshots of conformational substates sampled during enzymatic reactions, while NMR relaxation methods reveal the rates of interconversion between substates and the corresponding relative populations. However, these current methods cannot simultaneously reveal the detailed atomic structures of the rare states and rationalize the finding that intrinsic motions in the free enzyme occur on a timescale similar to the catalytic turnover rate. Here we introduce dual strategies of ambient-temperature X-ray crystallographic data collection and automated electron-density sampling to structurally unravel interconverting substates of the human proline isomerase, cyclophilin A (CYPA, also known as PPIA). A conservative mutation outside the active site was designed to stabilize features of the previously hidden minor conformation. This mutation not only inverts the equilibrium between the substates, but also causes large, parallel reductions in the conformational interconversion rates and the catalytic rate. These studies introduce crystallographic approaches to define functional minor protein conformations and, in combination with NMR analysis of the enzyme dynamics in solution, show how collective motions directly contribute to the catalytic power of an enzyme.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805857/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805857/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fraser, James S -- Clarkson, Michael W -- Degnan, Sheena C -- Erion, Renske -- Kern, Dorothee -- Alber, Tom -- R01 GM048958/GM/NIGMS NIH HHS/ -- R01 GM048958-16/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Dec 3;462(7273):669-73. doi: 10.1038/nature08615.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology/QB3, University of California, Berkeley, California 94720-3220, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19956261" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Crystallography, X-Ray/*methods ; Cyclophilin A/*chemistry/genetics ; Humans ; *Models, Molecular ; Mutation ; Protein Structure, Tertiary ; Temperature
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    Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions (2009)
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    Publication Date: 2009-05-16
    Description: At some stage in the origin of life, an informational polymer must have arisen by purely chemical means. According to one version of the 'RNA world' hypothesis this polymer was RNA, but attempts to provide experimental support for this have failed. In particular, although there has been some success demonstrating that 'activated' ribonucleotides can polymerize to form RNA, it is far from obvious how such ribonucleotides could have formed from their constituent parts (ribose and nucleobases). Ribose is difficult to form selectively, and the addition of nucleobases to ribose is inefficient in the case of purines and does not occur at all in the case of the canonical pyrimidines. Here we show that activated pyrimidine ribonucleotides can be formed in a short sequence that bypasses free ribose and the nucleobases, and instead proceeds through arabinose amino-oxazoline and anhydronucleoside intermediates. The starting materials for the synthesis-cyanamide, cyanoacetylene, glycolaldehyde, glyceraldehyde and inorganic phosphate-are plausible prebiotic feedstock molecules, and the conditions of the synthesis are consistent with potential early-Earth geochemical models. Although inorganic phosphate is only incorporated into the nucleotides at a late stage of the sequence, its presence from the start is essential as it controls three reactions in the earlier stages by acting as a general acid/base catalyst, a nucleophilic catalyst, a pH buffer and a chemical buffer. For prebiotic reaction sequences, our results highlight the importance of working with mixed chemical systems in which reactants for a particular reaction step can also control other steps.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Powner, Matthew W -- Gerland, Beatrice -- Sutherland, John D -- England -- Nature. 2009 May 14;459(7244):239-42. doi: 10.1038/nature08013.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19444213" target="_blank"〉PubMed〈/a〉
    Keywords: Acetaldehyde/analogs & derivatives/chemistry ; Acetylene/analogs & derivatives/chemistry ; Arabinose/analogs & derivatives/chemistry ; Buffers ; Catalysis ; Cyanamide/chemistry ; Glyceraldehyde/chemistry ; Hydrogen-Ion Concentration ; *Models, Chemical ; Nitriles/chemistry ; *Origin of Life ; Oxazoles/chemical synthesis/chemistry ; Phosphates/chemistry ; Phosphorylation ; Pyrimidines/*chemical synthesis/chemistry ; Ribonucleotides/*chemical synthesis/chemistry ; Ribose
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    Magnetic resonance imaging of pH in vivo using hyperpolarized 13C-labelled bicarbonate (2008)
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    Publication Date: 2008-05-30
    Description: As alterations in tissue pH underlie many pathological processes, the capability to image tissue pH in the clinic could offer new ways of detecting disease and response to treatment. Dynamic nuclear polarization is an emerging technique for substantially increasing the sensitivity of magnetic resonance imaging experiments. Here we show that tissue pH can be imaged in vivo from the ratio of the signal intensities of hyperpolarized bicarbonate (H(13)CO(3)(-)) and (13)CO(2) following intravenous injection of hyperpolarized H(13)CO(3)(-). The technique was demonstrated in a mouse tumour model, which showed that the average tumour interstitial pH was significantly lower than the surrounding tissue. Given that bicarbonate is an endogenous molecule that can be infused in relatively high concentrations into patients, we propose that this technique could be used clinically to image pathological processes that are associated with alterations in tissue pH, such as cancer, ischaemia and inflammation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gallagher, Ferdia A -- Kettunen, Mikko I -- Day, Sam E -- Hu, De-En -- Ardenkjaer-Larsen, Jan Henrik -- Zandt, Rene in 't -- Jensen, Pernille R -- Karlsson, Magnus -- Golman, Klaes -- Lerche, Mathilde H -- Brindle, Kevin M -- C197/A3514/Cancer Research UK/United Kingdom -- England -- Nature. 2008 Jun 12;453(7197):940-3. doi: 10.1038/nature07017. Epub 2008 May 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18509335" target="_blank"〉PubMed〈/a〉
    Keywords: Acid-Base Equilibrium ; Animals ; Bicarbonates/*metabolism ; Carbon Dioxide/metabolism ; Carbon Isotopes ; Carbonic Anhydrases/metabolism ; Catalysis ; Hydrogen-Ion Concentration ; Lymphoma/*diagnosis/*metabolism/pathology ; Magnetic Resonance Imaging/*methods ; Mice ; Neoplasm Transplantation ; Phantoms, Imaging
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    Pyruvate kinase M2 is a phosphotyrosine-binding protein (2008)
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    Publication Date: 2008-03-14
    Description: Growth factors stimulate cells to take up excess nutrients and to use them for anabolic processes. The biochemical mechanism by which this is accomplished is not fully understood but it is initiated by phosphorylation of signalling proteins on tyrosine residues. Using a novel proteomic screen for phosphotyrosine-binding proteins, we have made the observation that an enzyme involved in glycolysis, the human M2 (fetal) isoform of pyruvate kinase (PKM2), binds directly and selectively to tyrosine-phosphorylated peptides. We show that binding of phosphotyrosine peptides to PKM2 results in release of the allosteric activator fructose-1,6-bisphosphate, leading to inhibition of PKM2 enzymatic activity. We also provide evidence that this regulation of PKM2 by phosphotyrosine signalling diverts glucose metabolites from energy production to anabolic processes when cells are stimulated by certain growth factors. Collectively, our results indicate that expression of this phosphotyrosine-binding form of pyruvate kinase is critical for rapid growth in cancer cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Christofk, Heather R -- Vander Heiden, Matthew G -- Wu, Ning -- Asara, John M -- Cantley, Lewis C -- R01 GM056203/GM/NIGMS NIH HHS/ -- T32 CA009172/CA/NCI NIH HHS/ -- England -- Nature. 2008 Mar 13;452(7184):181-6. doi: 10.1038/nature06667.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Systems Biology.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18337815" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Site ; Animals ; Catalysis ; Cell Line ; Cell Proliferation/drug effects ; Cells/drug effects/metabolism ; HeLa Cells ; Humans ; Lysine/metabolism ; Models, Molecular ; Peptide Library ; Phosphotyrosine/*metabolism ; Protein Binding ; Proteomics ; Pyruvate Kinase/antagonists & inhibitors/*metabolism ; Substrate Specificity
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    The advent and development of organocatalysis (2008)
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    Publication Date: 2008-09-19
    Description: The use of small organic molecules as catalysts has been known for more than a century. But only in the past decade has organocatalysis become a thriving area of general concepts and widely applicable asymmetric reactions. Here I present my opinion on why the field of organocatalysis has blossomed so dramatically over the past decade.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉MacMillan, David W C -- R01 GM078201-01-01/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):304-8. doi: 10.1038/nature07367.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Merck Center for Catalysis at Princeton University, 116 Frick Laboratory, Princeton University, Princeton, New Jersey 08540, USA. dmacmill@princeton.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800128" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chemistry, Organic/*history/*methods ; History, 20th Century ; History, 21st Century ; Hydrogen Bonding ; Ions/chemistry
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    Computational biochemistry: old enzymes, new tricks (2008)
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    Publication Date: 2008-05-10
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ghirlanda, Giovanna -- England -- Nature. 2008 May 8;453(7192):164-6. doi: 10.1038/453164a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18464727" target="_blank"〉PubMed〈/a〉
    Keywords: Biochemistry/*methods ; Catalysis ; Computational Biology/*methods ; Directed Molecular Evolution/*methods ; Drug Design ; Drug Evaluation, Preclinical ; Enzymes/*chemistry/*metabolism ; Models, Molecular ; Protein Engineering/*methods
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    Towards a molecular understanding of shape selectivity (2008)
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    Publication Date: 2008-02-08
    Description: Shape selectivity is a simple concept: the transformation of reactants into products depends on how the processed molecules fit the active site of the catalyst. Nature makes abundant use of this concept, in that enzymes usually process only very few molecules, which fit their active sites. Industry has also exploited shape selectivity in zeolite catalysis for almost 50 years, yet our mechanistic understanding remains rather limited. Here we review shape selectivity in zeolite catalysis, and argue that a simple thermodynamic analysis of the molecules adsorbed inside the zeolite pores can explain which products form and guide the identification of zeolite structures that are particularly suitable for desired catalytic applications.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smit, Berend -- Maesen, Theo L M -- England -- Nature. 2008 Feb 7;451(7179):671-8. doi: 10.1038/nature06552.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre Europeen de Calcul Atomique Moleculaire (CECAM), Ecole Normale Superieure, 46 Allee d'Italie, 69364 Lyon Cedex 7, France. berend-smit@berkeley.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18256663" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Computational Biology ; Isomerism ; Substrate Specificity ; Thermodynamics ; Zeolites/*chemistry
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    Structure of the Tribolium castaneum telomerase catalytic subunit TERT (2008)
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    Details
    Publication Date: 2008-09-02
    Description: A common hallmark of human cancers is the overexpression of telomerase, a ribonucleoprotein complex that is responsible for maintaining the length and integrity of chromosome ends. Telomere length deregulation and telomerase activation is an early, and perhaps necessary, step in cancer cell evolution. Here we present the high-resolution structure of the Tribolium castaneum catalytic subunit of telomerase, TERT. The protein consists of three highly conserved domains, organized into a ring-like structure that shares common features with retroviral reverse transcriptases, viral RNA polymerases and B-family DNA polymerases. Domain organization places motifs implicated in substrate binding and catalysis in the interior of the ring, which can accommodate seven to eight bases of double-stranded nucleic acid. Modelling of an RNA-DNA heteroduplex in the interior of this ring demonstrates a perfect fit between the protein and the nucleic acid substrate, and positions the 3'-end of the DNA primer at the active site of the enzyme, providing evidence for the formation of an active telomerase elongation complex.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gillis, Andrew J -- Schuller, Anthony P -- Skordalakes, Emmanuel -- England -- Nature. 2008 Oct 2;455(7213):633-7. doi: 10.1038/nature07283. Epub 2008 Aug 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Gene Expression and Regulation Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18758444" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Animals ; Binding Sites ; Catalysis ; Catalytic Domain ; Conserved Sequence ; Crystallization ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Nucleotides/metabolism ; Protein Structure, Tertiary ; Telomerase/*chemistry/metabolism ; Tribolium/*enzymology
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    Highly efficient molybdenum-based catalysts for enantioselective alkene metathesis (2008)
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    Publication Date: 2008-11-18
    Description: Discovery of efficient catalysts is one of the most compelling objectives of modern chemistry. Chiral catalysts are in particularly high demand, as they facilitate synthesis of enantiomerically enriched small molecules that are critical to developments in medicine, biology and materials science. Especially noteworthy are catalysts that promote-with otherwise inaccessible efficiency and selectivity levels-reactions demonstrated to be of great utility in chemical synthesis. Here we report a class of chiral catalysts that initiate alkene metathesis with very high efficiency and enantioselectivity. Such attributes arise from structural fluxionality of the chiral catalysts and the central role that enhanced electronic factors have in the catalytic cycle. The new catalysts have a stereogenic metal centre and carry only monodentate ligands; the molybdenum-based complexes are prepared stereoselectively by a ligand exchange process involving an enantiomerically pure aryloxide, a class of ligands scarcely used in enantioselective catalysis. We demonstrate the application of the new catalysts in an enantioselective synthesis of the Aspidosperma alkaloid, quebrachamine, through an alkene metathesis reaction that cannot be promoted by any of the previously reported chiral catalysts.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663850/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663850/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Malcolmson, Steven J -- Meek, Simon J -- Sattely, Elizabeth S -- Schrock, Richard R -- Hoveyda, Amir H -- GM-59426/GM/NIGMS NIH HHS/ -- R01 GM059426/GM/NIGMS NIH HHS/ -- R01 GM059426-09/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Dec 18;456(7224):933-7. doi: 10.1038/nature07594. Epub 2008 Nov 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19011612" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/*chemistry ; Aspidosperma/*chemistry ; Catalysis ; Indole Alkaloids/*chemical synthesis/chemistry ; Ligands ; Molecular Structure ; Molybdenum/*chemistry ; Stereoisomerism
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    Isolation of an active step I spliceosome and composition of its RNP core (2008)
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    Publication Date: 2008-03-07
    Description: Formation of catalytically active RNA structures within the spliceosome requires the assistance of proteins. However, little is known about the number and nature of proteins needed to establish and maintain the spliceosome's active site. Here we affinity-purified human spliceosomal C complexes and show that they catalyse exon ligation in the absence of added factors. Comparisons of the composition of the precatalytic versus the catalytic spliceosome revealed a marked exchange of proteins during the transition from the B to the C complex, with apparent stabilization of Prp19-CDC5 complex proteins and destabilization of SF3a/b proteins. Disruption of purified C complexes led to the isolation of a salt-stable ribonucleoprotein (RNP) core that contained both splicing intermediates and U2, U5 and U6 small nuclear RNA plus predominantly U5 and human Prp19-CDC5 proteins and Prp19-related factors. Our data provide insights into the spliceosome's catalytic RNP domain and indicate a central role for the aforementioned proteins in sustaining its catalytically active structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bessonov, Sergey -- Anokhina, Maria -- Will, Cindy L -- Urlaub, Henning -- Luhrmann, Reinhard -- England -- Nature. 2008 Apr 17;452(7189):846-50. doi: 10.1038/nature06842. Epub 2008 Mar 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Gottingen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18322460" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Catalytic Domain ; Exons/genetics ; Humans ; Multiprotein Complexes/*chemistry/genetics/*isolation & purification ; RNA Splice Sites/genetics ; RNA Splicing ; RNA, Messenger/genetics/metabolism ; RNA, Small Nuclear/analysis/chemistry/genetics/isolation & purification ; Ribonucleoproteins/*analysis/*chemistry/genetics/isolation & purification ; Spliceosomes/*chemistry/*genetics
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    Structure of the sulphiredoxin-peroxiredoxin complex reveals an essential repair embrace (2008)
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    Publication Date: 2008-01-04
    Description: Typical 2-Cys peroxiredoxins (Prxs) have an important role in regulating hydrogen peroxide-mediated cell signalling. In this process, Prxs can become inactivated through the hyperoxidation of an active site Cys residue to Cys sulphinic acid. The unique repair of this moiety by sulphiredoxin (Srx) restores peroxidase activity and terminates the signal. The hyperoxidized form of Prx exists as a stable decameric structure with each active site buried. Therefore, it is unclear how Srx can access the sulphinic acid moiety. Here we present the 2.6 A crystal structure of the human Srx-PrxI complex. This complex reveals the complete unfolding of the carboxy terminus of Prx, and its unexpected packing onto the backside of Srx away from the Srx active site. Binding studies and activity analyses of site-directed mutants at this interface show that the interaction is required for repair to occur. Moreover, rearrangements in the Prx active site lead to a juxtaposition of the Prx Gly-Gly-Leu-Gly and Srx ATP-binding motifs, providing a structural basis for the first step of the catalytic mechanism. The results also suggest that the observed interactions may represent a common mode for other proteins to bind to Prxs.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2646140/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2646140/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jonsson, Thomas J -- Johnson, Lynnette C -- Lowther, W Todd -- R01 GM072866/GM/NIGMS NIH HHS/ -- R01 GM072866-03/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Jan 3;451(7174):98-101. doi: 10.1038/nature06415.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Structural Biology and Department of Biochemistry, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18172504" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites/genetics ; Catalysis ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Multiprotein Complexes/chemistry/genetics/metabolism ; Mutagenesis, Site-Directed ; Oxidation-Reduction ; Oxidoreductases/*chemistry/genetics/*metabolism ; Oxidoreductases Acting on Sulfur Group Donors ; Peroxiredoxins/*chemistry/genetics/*metabolism ; Protein Structure, Quaternary ; Structure-Activity Relationship
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    Biologically inspired oxidation catalysis (2008)
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    Publication Date: 2008-09-19
    Description: The development of processes for selective hydrocarbon oxidation is a goal that has long been pursued. An additional challenge is to make such processes environmentally friendly, for example by using non-toxic reagents and energy-efficient catalytic methods. Excellent examples are naturally occurring iron- or copper-containing metalloenzymes, and extensive studies have revealed the key chemical principles that underlie their efficacy as catalysts for aerobic oxidations. Important inroads have been made in applying this knowledge to the development of synthetic catalysts that model enzyme function. Such biologically inspired hydrocarbon oxidation catalysts hold great promise for wide-ranging synthetic applications.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Que, Lawrence Jr -- Tolman, William B -- England -- Nature. 2008 Sep 18;455(7211):333-40. doi: 10.1038/nature07371.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA. larryque@umn.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800132" target="_blank"〉PubMed〈/a〉
    Keywords: *Biomimetics ; Catalysis ; Copper/metabolism ; Enzymes/*chemistry/*metabolism ; Heme/chemistry/metabolism ; Iron/metabolism ; Oxidation-Reduction
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    Structure and metal exchange in the cadmium carbonic anhydrase of marine diatoms (2008)
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    Publication Date: 2008-03-07
    Description: Carbonic anhydrase, a zinc enzyme found in organisms from all kingdoms, catalyses the reversible hydration of carbon dioxide and is used for inorganic carbon acquisition by phytoplankton. In the oceans, where zinc is nearly depleted, diatoms use cadmium as a catalytic metal atom in cadmium carbonic anhydrase (CDCA). Here we report the crystal structures of CDCA in four distinct forms: cadmium-bound, zinc-bound, metal-free and acetate-bound. Despite lack of sequence homology, CDCA is a structural mimic of a functional beta-carbonic anhydrase dimer, with striking similarity in the spatial organization of the active site residues. CDCA readily exchanges cadmium and zinc at its active site--an apparently unique adaptation to oceanic life that is explained by a stable opening of the metal coordinating site in the absence of metal. Given the central role of diatoms in exporting carbon to the deep sea, their use of cadmium in an enzyme critical for carbon acquisition establishes a remarkable link between the global cycles of cadmium and carbon.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xu, Yan -- Feng, Liang -- Jeffrey, Philip D -- Shi, Yigong -- Morel, Francois M M -- England -- Nature. 2008 Mar 6;452(7183):56-61. doi: 10.1038/nature06636.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, Princeton University, New Jersey 08544, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18322527" target="_blank"〉PubMed〈/a〉
    Keywords: Acetates/metabolism ; Binding Sites ; Cadmium/*metabolism ; Carbonic Anhydrases/*chemistry/*metabolism ; Catalysis ; Crystallography, X-Ray ; Diatoms/*enzymology ; Dimerization ; Kinetics ; Marine Biology ; Models, Molecular ; Molecular Mimicry ; Protein Structure, Secondary ; Seawater/*microbiology ; Zinc/*metabolism
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    Catalytic C-H functionalization by metal carbenoid and nitrenoid insertion (2008)
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    Publication Date: 2008-01-25
    Description: Novel reactions that can selectively functionalize carbon-hydrogen bonds are of intense interest to the chemical community because they offer new strategic approaches for synthesis. A very promising 'carbon-hydrogen functionalization' method involves the insertion of metal carbenes and nitrenes into C-H bonds. This area has experienced considerable growth in the past decade, particularly in the area of enantioselective intermolecular reactions. Here we discuss several facets of these kinds of C-H functionalization reactions and provide a perspective on how this methodology has affected the synthesis of complex natural products and potential pharmaceutical agents.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033428/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033428/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Davies, Huw M L -- Manning, James R -- R01 DA006301/DA/NIDA NIH HHS/ -- R01 DA006301-13/DA/NIDA NIH HHS/ -- R01 DA015225/DA/NIDA NIH HHS/ -- R01 DA015225-05/DA/NIDA NIH HHS/ -- R01 GM080337/GM/NIGMS NIH HHS/ -- R01 GM080337-04/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Jan 24;451(7177):417-24. doi: 10.1038/nature06485.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University at Buffalo, the State University of New York, Buffalo, New York 14260-3000, USA. hdavies@buffalo.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18216847" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Products/chemical synthesis/chemistry ; Carbon/*chemistry ; Catalysis ; Hydrocarbons/*chemistry ; Hydrogen/*chemistry ; Pharmaceutical Preparations/chemical synthesis/chemistry
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    Proline-catalysed Mannich reactions of acetaldehyde (2008)
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    Publication Date: 2008-02-22
    Description: Small organic molecules recently emerged as a third class of broadly useful asymmetric catalysts that direct reactions to yield predominantly one chiral product, complementing enzymes and metal complexes. For instance, the amino acid proline and its derivatives are useful for the catalytic activation of carbonyl compounds via nucleophilic enamine intermediates. Several important carbon-carbon bond-forming reactions, including the Mannich reaction, have been developed using this approach, all of which are useful for making chiral, biologically relevant compounds. Remarkably, despite attempts, the simplest of all nucleophiles, acetaldehyde, could not be used in this way. Here we show that acetaldehyde is a powerful nucleophile in asymmetric, proline-catalysed Mannich reactions with N-tert-butoxycarbonyl (N-Boc)-imines, yielding beta-amino aldehydes with extremely high enantioselectivities-desirable products as drug intermediates and in the synthesis of other biologically active molecules. Although acetaldehyde has been used as a nucleophile in reactions with biological catalysts such as aldolases and thiamine-dependent enzymes, and has also been employed indirectly, its use as an inexpensive and versatile two-carbon nucleophile in asymmetric, small-molecule catalysis will find many practical applications.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yang, Jung Woon -- Chandler, Carley -- Stadler, Michael -- Kampen, Daniela -- List, Benjamin -- England -- Nature. 2008 Mar 27;452(7186):453-5. doi: 10.1038/nature06740. Epub 2008 Feb 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mulheim an der Ruhr, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18288105" target="_blank"〉PubMed〈/a〉
    Keywords: Acetaldehyde/*chemistry ; Biological Products/chemical synthesis/chemistry ; Carbon/chemistry ; Catalysis ; Imines/chemistry ; Mannich Bases/*chemistry ; Molecular Structure ; Peptides/chemical synthesis/chemistry ; Pharmaceutical Preparations/chemical synthesis/chemistry ; Proline/*chemistry
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    Catalysis: the art of splitting water (2008)
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    Publication Date: 2008-02-15
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer, Thomas J -- England -- Nature. 2008 Feb 14;451(7180):778-9. doi: 10.1038/451778a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18273008" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Hydrogen/chemistry ; Oxidation-Reduction ; Oxygen/chemistry ; Photosynthesis ; Water/*chemistry
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    Programming biomolecular self-assembly pathways (2008)
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    Publication Date: 2008-01-19
    Description: In nature, self-assembling and disassembling complexes of proteins and nucleic acids bound to a variety of ligands perform intricate and diverse dynamic functions. In contrast, attempts to rationally encode structure and function into synthetic amino acid and nucleic acid sequences have largely focused on engineering molecules that self-assemble into prescribed target structures, rather than on engineering transient system dynamics. To design systems that perform dynamic functions without human intervention, it is necessary to encode within the biopolymer sequences the reaction pathways by which self-assembly occurs. Nucleic acids show promise as a design medium for engineering dynamic functions, including catalytic hybridization, triggered self-assembly and molecular computation. Here, we program diverse molecular self-assembly and disassembly pathways using a 'reaction graph' abstraction to specify complementarity relationships between modular domains in a versatile DNA hairpin motif. Molecular programs are executed for a variety of dynamic functions: catalytic formation of branched junctions, autocatalytic duplex formation by a cross-catalytic circuit, nucleated dendritic growth of a binary molecular 'tree', and autonomous locomotion of a bipedal walker.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yin, Peng -- Choi, Harry M T -- Calvert, Colby R -- Pierce, Niles A -- England -- Nature. 2008 Jan 17;451(7176):318-22. doi: 10.1038/nature06451.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bioengineering, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18202654" target="_blank"〉PubMed〈/a〉
    Keywords: Biopolymers/chemistry/metabolism ; Catalysis ; *Computer Simulation ; DNA/*chemistry/*metabolism ; DNA, Concatenated/chemistry/metabolism ; Dendrimers/chemistry/metabolism ; Gait ; Kinetics ; Models, Biological ; *Nucleic Acid Conformation ; Stochastic Processes ; Walking
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    Small-molecule catalysis (2008)
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    Publication Date: 2008-09-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mitchinson, Andrew -- Finkelstein, Joshua -- England -- Nature. 2008 Sep 18;455(7211):303. doi: 10.1038/455303a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800127" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chemistry/*methods/trends
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    Natural products as inspiration for the development of asymmetric catalysis (2008)
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    Publication Date: 2008-09-19
    Description: Biologically active natural products often contain particularly challenging structural features and functionalities in terms of synthesis. Perhaps the greatest difficulties are those caused by issues of stereochemistry. A useful strategy for synthesizing such molecules is to devise methods of bond formation that provide opportunities for using enantioselective catalysis. In using this tactic, the desire for a particular target structure ultimately drives the development of catalytic methods. New enantioselective catalytic methods contribute to a greater fundamental understanding of how bonds can be constructed and lead to valuable synthetic technologies that are useful for a variety of applications.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2562237/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2562237/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mohr, Justin T -- Krout, Michael R -- Stoltz, Brian M -- R01 GM080269/GM/NIGMS NIH HHS/ -- R01 GM080269-01/GM/NIGMS NIH HHS/ -- R01GM080269-01/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):323-32. doi: 10.1038/nature07370.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 164-30, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800131" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Products/*chemical synthesis/*chemistry ; Carbazoles/chemical synthesis/chemistry ; Catalysis ; Diterpenes/chemical synthesis/chemistry ; Indans/chemical synthesis/chemistry ; Indole Alkaloids/chemical synthesis/chemistry ; Indolizines/chemical synthesis/chemistry ; Lactams/chemical synthesis/chemistry ; Pyrazines/chemical synthesis/chemistry ; Sitagliptin Phosphate ; Spiro Compounds/chemical synthesis/chemistry ; Triazoles/chemical synthesis/chemistry
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    Kemp elimination catalysts by computational enzyme design (2008)
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    Publication Date: 2008-03-21
    Description: The design of new enzymes for reactions not catalysed by naturally occurring biocatalysts is a challenge for protein engineering and is a critical test of our understanding of enzyme catalysis. Here we describe the computational design of eight enzymes that use two different catalytic motifs to catalyse the Kemp elimination-a model reaction for proton transfer from carbon-with measured rate enhancements of up to 10(5) and multiple turnovers. Mutational analysis confirms that catalysis depends on the computationally designed active sites, and a high-resolution crystal structure suggests that the designs have close to atomic accuracy. Application of in vitro evolution to enhance the computational designs produced a 〉200-fold increase in k(cat)/K(m) (k(cat)/K(m) of 2,600 M(-1)s(-1) and k(cat)/k(uncat) of 〉10(6)). These results demonstrate the power of combining computational protein design with directed evolution for creating new enzymes, and we anticipate the creation of a wide range of useful new catalysts in the future.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rothlisberger, Daniela -- Khersonsky, Olga -- Wollacott, Andrew M -- Jiang, Lin -- DeChancie, Jason -- Betker, Jamie -- Gallaher, Jasmine L -- Althoff, Eric A -- Zanghellini, Alexandre -- Dym, Orly -- Albeck, Shira -- Houk, Kendall N -- Tawfik, Dan S -- Baker, David -- Howard Hughes Medical Institute/ -- England -- Nature. 2008 May 8;453(7192):190-5. doi: 10.1038/nature06879. Epub 2008 Mar 19.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18354394" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Amino Acid Motifs ; Binding Sites/genetics ; Catalysis ; Computational Biology ; *Computer Simulation ; Crystallography, X-Ray ; Directed Molecular Evolution/*methods ; Drug Design ; Drug Evaluation, Preclinical ; Enzymes/*chemistry/genetics/*metabolism ; Kinetics ; Models, Chemical ; Models, Molecular ; Protein Engineering/*methods ; Quantum Theory ; Sensitivity and Specificity
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    Organometallic chemistry: catalyst takes control to heart (2008)
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    Publication Date: 2008-12-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Diver, Steven T -- England -- Nature. 2008 Dec 18;456(7224):883-5. doi: 10.1038/456883a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19092919" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/*chemistry ; Aspidosperma/*chemistry ; Catalysis ; Indole Alkaloids/*chemical synthesis/chemistry ; Molybdenum/*chemistry ; Stereoisomerism
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    Chemistry: the photon trap (2008)
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    Publication Date: 2008-03-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanderson, Katharine -- England -- Nature. 2008 Mar 27;452(7186):400-2. doi: 10.1038/452400a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18368093" target="_blank"〉PubMed〈/a〉
    Keywords: Biomimetics/*methods ; Catalysis ; Electron Transport ; *Energy-Generating Resources ; Hydrogen/chemistry ; Metal Nanoparticles/chemistry ; Oxygen/chemistry ; *Photons ; *Photosynthesis/radiation effects ; Photosystem II Protein Complex/metabolism ; Plants/metabolism/radiation effects ; Ruthenium/chemistry ; Semiconductors ; Silicon/chemistry ; *Sunlight ; Water/chemistry
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    Dynamic binding orientations direct activity of HIV reverse transcriptase (2008)
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    Publication Date: 2008-05-10
    Description: The reverse transcriptase of human immunodeficiency virus (HIV) catalyses a series of reactions to convert the single-stranded RNA genome of HIV into double-stranded DNA for host-cell integration. This task requires the reverse transcriptase to discriminate a variety of nucleic-acid substrates such that active sites of the enzyme are correctly positioned to support one of three catalytic functions: RNA-directed DNA synthesis, DNA-directed DNA synthesis and DNA-directed RNA hydrolysis. However, the mechanism by which substrates regulate reverse transcriptase activities remains unclear. Here we report distinct orientational dynamics of reverse transcriptase observed on different substrates with a single-molecule assay. The enzyme adopted opposite binding orientations on duplexes containing DNA or RNA primers, directing its DNA synthesis or RNA hydrolysis activity, respectively. On duplexes containing the unique polypurine RNA primers for plus-strand DNA synthesis, the enzyme can rapidly switch between the two orientations. The switching kinetics were regulated by cognate nucleotides and non-nucleoside reverse transcriptase inhibitors, a major class of anti-HIV drugs. These results indicate that the activities of reverse transcriptase are determined by its binding orientation on substrates.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2655135/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2655135/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abbondanzieri, Elio A -- Bokinsky, Gregory -- Rausch, Jason W -- Zhang, Jennifer X -- Le Grice, Stuart F J -- Zhuang, Xiaowei -- GM 068518/GM/NIGMS NIH HHS/ -- R01 GM068518/GM/NIGMS NIH HHS/ -- R01 GM068518-05/GM/NIGMS NIH HHS/ -- Z01 BC010493-05/Intramural NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2008 May 8;453(7192):184-9. doi: 10.1038/nature06941.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18464735" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; DNA/*biosynthesis ; DNA Primers/genetics/metabolism ; *DNA Replication ; Fluorescence Resonance Energy Transfer ; HIV/*enzymology/genetics ; HIV Reverse Transcriptase/*chemistry/*metabolism ; Hydrolysis ; Ligands ; RNA/genetics/*metabolism ; *Reverse Transcription ; Substrate Specificity ; Templates, Genetic
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    Total synthesis of bryostatin 16 using atom-economical and chemoselective approaches (2008)
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    Publication Date: 2008-11-28
    Description: Of the concepts used to improve the efficiency of organic syntheses, two have been especially effective: atom economy (the use of routes in which most of the atoms present in the reactants also end up in the product) and chemoselectivity (the use of reactions that take place only at desired positions in a molecule). Synthesis of complex natural products is the most demanding arena in which to explore such principles. The bryostatin family of compounds are especially interesting targets, because they combine structural complexity with promising biological activity. Furthermore, synthetic routes to some bryostatins have already been reported, providing a benchmark against which new syntheses can be measured. Here we report a concise total synthesis of bryostatin 16 (1), a parent structure from which almost all other bryostatins could in principle be accessed. Application of atom-economical and chemoselective reactions currently under development provides ready access to polyhydropyran motifs in the molecule, which are common structural features of many other natural products. The most notable transformations are two transition-metal-catalysed reactions. The first is a palladium-catalysed reaction of two different alkynes to form a large ring. The product of this step is then converted into a dihydropyran (the 'C ring' of bryostatins) in the second key reaction, which is catalysed by a gold compound. Analogues of bryostatin that do not exist in nature could be readily made by following this route, which might allow the biological activity of bryostatins to be fine-tuned.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2728752/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2728752/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Trost, Barry M -- Dong, Guangbin -- GM 13598/GM/NIGMS NIH HHS/ -- R01 GM013598/GM/NIGMS NIH HHS/ -- R01 GM013598-42/GM/NIGMS NIH HHS/ -- R01 GM013598-43/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Nov 27;456(7221):485-8. doi: 10.1038/nature07543.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA. bmtrost@stanford.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19037312" target="_blank"〉PubMed〈/a〉
    Keywords: Acids/chemical synthesis ; Alcohols/chemical synthesis ; Alkenes/chemical synthesis ; Alkynes/chemical synthesis ; Animals ; Antineoplastic Agents/*chemical synthesis/chemistry ; Biological Products/*chemical synthesis/chemistry ; Bryostatins/*chemical synthesis/chemistry ; Bryozoa/chemistry ; Catalysis ; Molecular Structure
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    Carbon-heteroatom bond formation catalysed by organometallic complexes (2008)
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    Publication Date: 2008-09-19
    Description: At one time the synthetic chemist's last resort, reactions catalysed by transition metals are now the preferred method for synthesizing many types of organic molecule. A recent success in this type of catalysis is the discovery of reactions that form bonds between carbon and heteroatoms (such as nitrogen, oxygen, sulphur, silicon and boron) via complexes of transition metals with amides, alkoxides, thiolates, silyl groups or boryl groups. The development of these catalytic processes has been supported by the discovery of new elementary reactions that occur at metal-heteroatom bonds and by the identification of factors that control these reactions. Together, these findings have led to new synthetic processes that are in daily use and have formed a foundation for the development of processes that are likely to be central to synthetic chemistry in the future.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819340/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819340/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hartwig, John F -- R01 GM058108/GM/NIGMS NIH HHS/ -- R01 GM058108-12/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):314-22. doi: 10.1038/nature07369.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA. jhartwig@uiuc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800130" target="_blank"〉PubMed〈/a〉
    Keywords: Alkenes/chemistry ; Carbon/*chemistry ; Catalysis ; Hydrogen/chemistry ; Metals/chemistry ; Organometallic Compounds/*chemistry
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    Structural basis for specific cleavage of Lys 63-linked polyubiquitin chains (2008)
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    Publication Date: 2008-09-02
    Description: Deubiquitinating enzymes (DUBs) remove ubiquitin from conjugated substrates to regulate various cellular processes. The Zn(2+)-dependent DUBs AMSH and AMSH-LP regulate receptor trafficking by specifically cleaving Lys 63-linked polyubiquitin chains from internalized receptors. Here we report the crystal structures of the human AMSH-LP DUB domain alone and in complex with a Lys 63-linked di-ubiquitin at 1.2 A and 1.6 A resolutions, respectively. The AMSH-LP DUB domain consists of a Zn(2+)-coordinating catalytic core and two characteristic insertions, Ins-1 and Ins-2. The distal ubiquitin interacts with Ins-1 and the core, whereas the proximal ubiquitin interacts with Ins-2 and the core. The core and Ins-1 form a catalytic groove that accommodates the Lys 63 side chain of the proximal ubiquitin and the isopeptide-linked carboxy-terminal tail of the distal ubiquitin. This is the first reported structure of a DUB in complex with an isopeptide-linked ubiquitin chain, which reveals the mechanism for Lys 63-linkage-specific deubiquitination by AMSH family members.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sato, Yusuke -- Yoshikawa, Azusa -- Yamagata, Atsushi -- Mimura, Hisatoshi -- Yamashita, Masami -- Ookata, Kayoko -- Nureki, Osamu -- Iwai, Kazuhiro -- Komada, Masayuki -- Fukai, Shuya -- England -- Nature. 2008 Sep 18;455(7211):358-62. doi: 10.1038/nature07254. Epub 2008 Aug 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural Biology Laboratory, Life Science Division, Synchrotron Radiation Research Organization and Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18758443" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Catalysis ; Conserved Sequence ; Crystallography, X-Ray ; Endopeptidases/chemistry/metabolism ; Endosomal Sorting Complexes Required for Transport ; Humans ; Kinetics ; Lysine/*metabolism ; Mice ; Models, Molecular ; Polyubiquitin/*chemistry/genetics/*metabolism ; Protein Structure, Tertiary ; Saccharomyces cerevisiae Proteins/chemistry/metabolism ; Structure-Activity Relationship ; Substrate Specificity ; Ubiquitin Thiolesterase/*chemistry/genetics/*metabolism
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    The total synthesis of (-)-cyanthiwigin F by means of double catalytic enantioselective alkylation (2008)
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    Publication Date: 2008-06-27
    Description: Double catalytic enantioselective transformations are powerful synthetic methods that can facilitate the construction of stereochemically complex molecules in a single operation. In addition to generating two or more stereocentres in a single reaction, multiple asymmetric reactions also impart increased enantiomeric excess to the final product in comparison with the analogous single transformation. Furthermore, multiple asymmetric operations have the potential to independently construct several stereocentres at remote points within the same molecular scaffold, rather than relying on pre-existing chiral centres that are proximal to the reactive site. Despite the inherent benefits of multiple catalytic enantioselective reactions, their application to natural product total synthesis remains largely underutilized. Here we report the use of a double stereoablative enantioselective alkylation reaction in a concise synthesis of the marine diterpenoid (-)-cyanthiwigin F (ref. 8). By employing a technique for independent, selective formation of two stereocentres in a single stereoconvergent operation, we demonstrate that a complicated mixture of racemic and meso diastereomers may be smoothly converted to a synthetically useful intermediate with exceptional enantiomeric excess. The stereochemical information generated by means of this catalytic transformation facilitates the easy and rapid completion of the total synthesis of this marine natural product.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2474750/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2474750/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Enquist, John A Jr -- Stoltz, Brian M -- R01 GM080269/GM/NIGMS NIH HHS/ -- R01 GM080269-01/GM/NIGMS NIH HHS/ -- R01GM080269-01/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Jun 26;453(7199):1228-31. doi: 10.1038/nature07046.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC164-30, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18580947" target="_blank"〉PubMed〈/a〉
    Keywords: Alkylation ; Animals ; Biological Products/*chemical synthesis/chemistry ; Catalysis ; Diterpenes/*chemical synthesis/chemistry ; Ketones/chemical synthesis ; Molecular Structure ; Porifera/chemistry
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    Structural insights into the evolutionary paths of oxylipin biosynthetic enzymes (2008)
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    Publication Date: 2008-08-22
    Description: The oxylipin pathway generates not only prostaglandin-like jasmonates but also green leaf volatiles (GLVs), which confer characteristic aromas to fruits and vegetables. Although allene oxide synthase (AOS) and hydroperoxide lyase are atypical cytochrome P450 family members involved in the synthesis of jasmonates and GLVs, respectively, it is unknown how these enzymes rearrange their hydroperoxide substrates into different products. Here we present the crystal structures of Arabidopsis thaliana AOS, free and in complex with substrate or intermediate analogues. The structures reveal an unusual active site poised to control the reactivity of an epoxyallylic radical and its cation by means of interactions with an aromatic pi-system. Replacing the amino acid involved in these steps by a non-polar residue markedly reduces AOS activity and, unexpectedly, is both necessary and sufficient for converting AOS into a GLV biosynthetic enzyme. Furthermore, by combining our structural data with bioinformatic and biochemical analyses, we have discovered previously unknown hydroperoxide lyase in plant growth-promoting rhizobacteria, AOS in coral, and epoxyalcohol synthase in amphioxus. These results indicate that oxylipin biosynthetic genes were present in the last common ancestor of plants and animals, but were subsequently lost in all metazoan lineages except Placozoa, Cnidaria and Cephalochordata.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, Dong-Sun -- Nioche, Pierre -- Hamberg, Mats -- Raman, C S -- R01 AI054444/AI/NIAID NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):363-8. doi: 10.1038/nature07307. Epub 2008 Aug 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18716621" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arabidopsis/enzymology/genetics ; Binding Sites ; Catalysis ; Cytochrome P-450 Enzyme System/chemistry/metabolism ; *Evolution, Molecular ; Intramolecular Oxidoreductases/*chemistry/genetics/*metabolism ; Models, Chemical ; Models, Molecular ; Molecular Sequence Data ; Oxylipins/*metabolism ; Point Mutation/genetics ; Protein Conformation
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    Organic chemistry: Short cuts to complexity (2008)
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    Publication Date: 2008-11-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Charette, Andre B -- England -- Nature. 2008 Nov 27;456(7221):451-3. doi: 10.1038/456451a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19037302" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antineoplastic Agents/*chemical synthesis/chemistry ; Biological Products/*chemical synthesis/chemistry ; Bryostatins/*chemical synthesis/chemistry ; Bryozoa/chemistry ; Catalysis ; Molecular Structure
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    Molecular biology: an HIV secret uncovered (2008)
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    Publication Date: 2008-05-10
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Arnold, Eddy -- Sarafianos, Stefan G -- England -- Nature. 2008 May 8;453(7192):169-70. doi: 10.1038/453169b.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18464731" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; DNA Primers/genetics/metabolism ; *DNA Replication ; HIV/*enzymology/genetics ; HIV Reverse Transcriptase/*chemistry/*metabolism ; Ligands ; Models, Molecular ; RNA/genetics/*metabolism ; *Reverse Transcription ; Substrate Specificity ; Templates, Genetic
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    Structure of the DNA deaminase domain of the HIV-1 restriction factor APOBEC3G (2008)
    Nature Publishing Group (NPG)
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    Publication Date: 2008-02-22
    Description: The human APOBEC3G (apolipoprotein B messenger-RNA-editing enzyme, catalytic polypeptide-like 3G) protein is a single-strand DNA deaminase that inhibits the replication of human immunodeficiency virus-1 (HIV-1), other retroviruses and retrotransposons. APOBEC3G anti-viral activity is circumvented by most retroelements, such as through degradation by HIV-1 Vif. APOBEC3G is a member of a family of polynucleotide cytosine deaminases, several of which also target distinct physiological substrates. For instance, APOBEC1 edits APOB mRNA and AID deaminates antibody gene DNA. Although structures of other family members exist, none of these proteins has elicited polynucleotide cytosine deaminase or anti-viral activity. Here we report a solution structure of the human APOBEC3G catalytic domain. Five alpha-helices, including two that form the zinc-coordinating active site, are arranged over a hydrophobic platform consisting of five beta-strands. NMR DNA titration experiments, computational modelling, phylogenetic conservation and Escherichia coli-based activity assays combine to suggest a DNA-binding model in which a brim of positively charged residues positions the target cytosine for catalysis. The structure of the APOBEC3G catalytic domain will help us to understand functions of other family members and interactions that occur with pathogenic proteins such as HIV-1 Vif.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Kuan-Ming -- Harjes, Elena -- Gross, Phillip J -- Fahmy, Amr -- Lu, Yongjian -- Shindo, Keisuke -- Harris, Reuben S -- Matsuo, Hiroshi -- R21 AI073167/AI/NIAID NIH HHS/ -- England -- Nature. 2008 Mar 6;452(7183):116-9. doi: 10.1038/nature06638. Epub 2008 Feb 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Molecular Biology and Biophysics, [of Minnesota, Minneapolis, Minnesota 55455, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18288108" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; *Catalytic Domain ; Cytidine Deaminase/*chemistry/genetics/*metabolism ; DNA, Single-Stranded/chemistry/metabolism ; DNA-Binding Proteins/chemistry/genetics/metabolism ; HIV-1/*physiology ; Humans ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; *Nuclear Magnetic Resonance, Biomolecular ; Protein Structure, Secondary ; Zinc/metabolism
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    Towards uranium catalysts (2008)
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    Details
    Publication Date: 2008-09-19
    Description: The forefront of research into the complexes of uranium reveals chemical transformations that challenge and expand our view of this unique element. Certain ligands form multiple bonds to uranium, and small, inert molecules such as nitrogen and carbon dioxide become reactive when in complex with the metal. Such complexes provide clues to the catalytic future of uranium, in which the applications of the element extend far beyond the nuclear industry. Most excitingly, the ability of uranium to use its outermost f electrons for binding ligands might enable the element to catalyse reactions that are impossible with conventional, transition-metal catalysts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fox, Alexander R -- Bart, Suzanne C -- Meyer, Karsten -- Cummins, Christopher C -- England -- Nature. 2008 Sep 18;455(7211):341-9. doi: 10.1038/nature07372.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Room 6-435, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-2307, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800133" target="_blank"〉PubMed〈/a〉
    Keywords: Amines/chemistry ; Carbon Dioxide/chemistry ; Carbon Monoxide/chemistry ; Catalysis ; Hydrogen/chemistry ; Nitrogen/chemistry ; Uranium/*chemistry
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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    The structural basis of protein acetylation by the p300/CBP transcriptional coactivator (2008)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2008-02-15
    Description: The transcriptional coactivator p300/CBP (CREBBP) is a histone acetyltransferase (HAT) that regulates gene expression by acetylating histones and other transcription factors. Dysregulation of p300/CBP HAT activity contributes to various diseases including cancer. Sequence alignments, enzymology experiments and inhibitor studies on p300/CBP have led to contradictory results about its catalytic mechanism and its structural relation to the Gcn5/PCAF and MYST HATs. Here we describe a high-resolution X-ray crystal structure of a semi-synthetic heterodimeric p300 HAT domain in complex with a bi-substrate inhibitor, Lys-CoA. This structure shows that p300/CBP is a distant cousin of other structurally characterized HATs, but reveals several novel features that explain the broad substrate specificity and preference for nearby basic residues. Based on this structure and accompanying biochemical data, we propose that p300/CBP uses an unusual 'hit-and-run' (Theorell-Chance) catalytic mechanism that is distinct from other characterized HATs. Several disease-associated mutations can also be readily accounted for by the p300 HAT structure. These studies pave the way for new epigenetic therapies involving modulation of p300/CBP HAT activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Xin -- Wang, Ling -- Zhao, Kehao -- Thompson, Paul R -- Hwang, Yousang -- Marmorstein, Ronen -- Cole, Philip A -- England -- Nature. 2008 Feb 14;451(7180):846-50. doi: 10.1038/nature06546.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Program in Gene Expression and Regulation, The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18273021" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylation ; Amino Acid Sequence ; Catalysis ; Crystallography, X-Ray ; Dimerization ; Histone Acetyltransferases/antagonists & inhibitors/chemical ; synthesis/*chemistry/*metabolism ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Protein Structure, Tertiary ; Structure-Activity Relationship ; p300-CBP Transcription Factors/antagonists & inhibitors/chemical ; synthesis/*chemistry/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    Dynamic thiolation-thioesterase structure of a non-ribosomal peptide synthetase (2008)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2008-08-16
    Description: Non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) produce numerous secondary metabolites with various therapeutic/antibiotic properties. Like fatty acid synthases (FAS), these enzymes are organized in modular assembly lines in which each module, made of conserved domains, incorporates a given monomer unit into the growing chain. Knowledge about domain or module interactions may enable reengineering of this assembly line enzymatic organization and open avenues for the design of new bioactive compounds with improved therapeutic properties. So far, little structural information has been available on how the domains interact and communicate. This may be because of inherent interdomain mobility hindering crystallization, or because crystallized molecules may not represent the active domain orientations. In solution, the large size and internal dynamics of multidomain fragments (〉35 kilodaltons) make structure determination by nuclear magnetic resonance a challenge and require advanced technologies. Here we present the solution structure of the apo-thiolation-thioesterase (T-TE) di-domain fragment of the Escherichia coli enterobactin synthetase EntF NRPS subunit. In the holoenzyme, the T domain carries the growing chain tethered to a 4'-phosphopantetheine whereas the TE domain catalyses hydrolysis and cyclization of the iron chelator enterobactin. The T-TE di-domain forms a compact but dynamic structure with a well-defined domain interface; the two active sites are at a suitable distance for substrate transfer from T to TE. We observe extensive interdomain and intradomain motions for well-defined regions and show that these are modulated by interactions with proteins that participate in the biosynthesis. The T-TE interaction described here provides a model for NRPS, PKS and FAS function in general as T-TE-like di-domains typically catalyse the last step in numerous assembly-line chain-termination machineries.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2597408/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2597408/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Frueh, Dominique P -- Arthanari, Haribabu -- Koglin, Alexander -- Vosburg, David A -- Bennett, Andrew E -- Walsh, Christopher T -- Wagner, Gerhard -- EB 002026/EB/NIBIB NIH HHS/ -- GM066360/GM/NIGMS NIH HHS/ -- GM47467/GM/NIGMS NIH HHS/ -- P01 GM047467/GM/NIGMS NIH HHS/ -- P01 GM047467-11/GM/NIGMS NIH HHS/ -- P01 GM047467-110009/GM/NIGMS NIH HHS/ -- P01 GM047467-12/GM/NIGMS NIH HHS/ -- P01 GM047467-13/GM/NIGMS NIH HHS/ -- P01 GM047467-14/GM/NIGMS NIH HHS/ -- P01 GM047467-15/GM/NIGMS NIH HHS/ -- P01 GM047467-16/GM/NIGMS NIH HHS/ -- P01 GM047467-160012/GM/NIGMS NIH HHS/ -- P01 GM047467-17/GM/NIGMS NIH HHS/ -- P01 GM047467-170012/GM/NIGMS NIH HHS/ -- P41 EB002026/EB/NIBIB NIH HHS/ -- P41 EB002026-28/EB/NIBIB NIH HHS/ -- P41 EB002026-29/EB/NIBIB NIH HHS/ -- P41 EB002026-30/EB/NIBIB NIH HHS/ -- P41 EB002026-31/EB/NIBIB NIH HHS/ -- P41 EB002026-32/EB/NIBIB NIH HHS/ -- P41 EB002026-33/EB/NIBIB NIH HHS/ -- P41 GM066360/GM/NIGMS NIH HHS/ -- P41 GM066360-01/GM/NIGMS NIH HHS/ -- P41 GM066360-02/GM/NIGMS NIH HHS/ -- P41 GM066360-03/GM/NIGMS NIH HHS/ -- P41 GM066360-04/GM/NIGMS NIH HHS/ -- P41 GM066360-05/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Aug 14;454(7206):903-6. doi: 10.1038/nature07162.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA. dominique_frueh@hms.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18704088" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Enterobactin/biosynthesis ; Escherichia coli/*enzymology/genetics ; Ligases/*chemistry/genetics/*metabolism ; Models, Molecular ; Multienzyme Complexes/*chemistry/genetics/*metabolism ; Nuclear Magnetic Resonance, Biomolecular ; *Peptide Biosynthesis, Nucleic Acid-Independent ; Protein Structure, Tertiary ; Protein Subunits/chemistry/genetics/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 95
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    Computational prediction of small-molecule catalysts (2008)
    Nature Publishing Group (NPG)
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    Publication Date: 2008-09-19
    Description: Most organic and organometallic catalysts have been discovered through serendipity or trial and error, rather than by rational design. Computational methods, however, are rapidly becoming a versatile tool for understanding and predicting the roles of such catalysts in asymmetric reactions. Such methods should now be regarded as a first line of attack in the design of catalysts.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717898/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717898/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Houk, K N -- Cheong, Paul Ha-Yeon -- GM 36700/GM/NIGMS NIH HHS/ -- R01 GM036700/GM/NIGMS NIH HHS/ -- R01 GM036700-23/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):309-13. doi: 10.1038/nature07368.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of California, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA. houk@chem.ucla.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18800129" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chemistry/history/*methods ; *Computational Biology/history ; *Computer Simulation ; Drug Design ; History, 20th Century ; History, 21st Century ; Kinetics ; Molecular Structure
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    Analysis of self-organised criticality in the Olami-Feder-Christensen model and in real earthquakes (2007)
    American Physical Society
    Details
    Publication Date: 2017-04-04
    Description: We perform an analysis on the dissipative Olami-Feder-Christensen model on a small world topology considering avalanche size differences. We show that when criticality appears, the probability density functions (PDFs) for the avalanche size differences at different times have fat tails with a q-Gaussian shape. This behavior does not depend on the time interval adopted and is found also when considering energy differences between real earthquakes. Such a result can be analytically understood if the sizes (released energies) of the avalanches (earthquakes) have no correlations. Our findings support the hypothesis that a self-organized criticality mechanism with long-range interactions is at the origin of seismic events and indicate that it is not possible to predict the magnitude of the next earthquake knowing those of the previous ones.
    Description: Published
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: SOC, earthquakes interaction ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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