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  • Organic Chemistry  (23)
  • General Chemistry  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 196-202 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three-Oxygen-Transfer to the Olefinic Double Bond of 1,2-Diphenylacenaphthylene and of 1,2-Diphenyl-3,3,4,4-tetramethylcyclobuteneThe olefinic double bond of 1,2-diphenylacenaphthylene (1) is cleaved into its ozonide 2 (respectively into its Baeyer-Villiger rearrangement product 3) via two independent pathways: Pathway A represents the classical ozonolysis (simultaneous three-oxygen transfer) followed by a Baeyer-Villiger rearrangement, pathway B utilizes a two-step three-oxygen transfer; usual epoxidation (mono-oxygen transfer) is followed by C,C homolysis yielding a deep red diradical which shows fast two-oxygen addition (two-oxygen transfer) of molecular oxygen. The labile intermediate ozonide 2 suffers quantitative Baeyer-Villiger rearrangement under reaction conditions necessary to achieve oxirane C,C-cleavage. Therefore, the particularly stable ozonide 11 from 1,2-diphenyl-3,3,4,4-tetramethylcyclobutene (10) is prepared according to pathway B starting from Arnolds's oxirane 12. Both oxidation methods are compared with regard to ozonide formations from olefins.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 558-561 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ozonolysis of Enol Ethers. 9. Synthesis and Ozonolysis of 5,6,7,8-TetrahydrochromanThe regioselectivity of the transfer of three oxygens of ozone to the olefinic carbons of the rigid substituted enol ether 5,6,7,8-tetrahydrochroman (3) is proved by isolation of ω-caprinolactone 5 instead of an earlier claimed oxacyclodecanone 4.
    Additional Material: 1 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 409-412 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Details on Ozonolyses of Substituted Cyclopentenes
    Additional Material: 1 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 547-553 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Sulfonyl Ethers, 17.-Acylation of the Anions of Arylsulfonylmethyl Methyl Ethersα-Arylsulfonyl-α-methoxyacetic acids 2 and their esters 4a -c, α-arylsulfonyl-α-methoxy ketones 4d-o, and α-methoxy-β-disulfones 6 are obtained by acylation of α-metalated α-sulfonyl ethers 1. Reaction conditions and properties are described.
    Notes: Aus α-metallierten α-Sulfonylethern 1 werden durch gezielte Acylierung α-Arylsulfonyl-α-methoxyessigsäuren 2 sowie deren Ester 4a-c, α-Arylsulfonyl-α-methoxyketone 4d-o und α-Methoxy-β-disulfone 6 erhalten. Reaktionsbedingungen und Eigenschaften werden beschrieben.
    Additional Material: 6 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1739-1743 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Oxosulfones, 5. - reactions of a Cyclic α-Ketosulfone5,5-Dioxo-6H-dibenzo[b,d]thiopyran-6-one (4) as the first „real α-ketosulfone“ was isolated, and some of its reactions were studied. Apparently, 4 represents formally a border case between a thioester S,S-dioxide and an „α-ketosulfone“.
    Notes: Als erstes „wirkliches α-Ketosulfon“ wurde 5,5-Dioxo-6H-dibenzo[b,d]-thiopyran-6-on (4) isoliert. Beim Studium einiger seiner Reaktionen zeigte sich, daß 4 formal einen Grenzfall zwischen einem Carbonsäurethioester-S,S-dioxid und einem „α-Ketosulfon“ darstellt.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1977-1991 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Oxosulfones, 2.  -  Synthesis of α-Oxosulfones by OzonolysisThe hitherto unknown α-oxosulfones 2 have been synthesized by ozonolytic cleavage of α-diazosulfones 1 (method A) or α-(methoxymethylene)sulfones 6 (method B).
    Notes: Durch Ozonspaltung von α-Diazosulfonen 1 (Methode A) oder von α-(Methoxymethylen)sulfonen 6 (Methode B) in aprotischem Medium werden bisher nicht bekannte α-Oxosulfone 2 hergestellt.
    Additional Material: 6 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1477-1481 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Oxosulfones, 3.  -  Reactions of Acyclic α-OxosulfonesThe course of reactions of acyclic α-oxosulfones with protic and aprotic nucleophiles is described. A far-reaching analogy to reactions of acyl halides is noticed.
    Notes: Die Reaktionsweise von acyclischen α-Oxosulfonen mit protischen und aprotischen Nucleophilen wird beschrieben. Dabei wird eine weitgehende Analogie zu Reaktionen von Acylhalogeniden festgestellt.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1676-1682 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Sulfonyl Ethers, 15. - Peterson Olefination of α-Silylated α-(Arenesulfonyl) Dimethyl EthersWith respect to a spatial estimation of the influence of the anisotropy of a sulfonyl group upon the 1H-NMR chemical shift of protons within the external area of S = O bonds near the oxygen we prepared, inter alia, α-isopropylidene and α-ethylidene substituted α-sulfonyl ethers by the method of Peterson. Special features of the synthesis as well as the assignment of the 1H-NMR-signals using shift reagents are reported.
    Notes: Im Hinblick auf eine räumliche Abschätzung des Einflusses der Anisotropie einer Sulfonyl-gruppe auf die 1H-NMR-chemische Verschiebung von Protonen im Außenbereich von S = O-Bindungen in Sauerstoffnähe werden unter anderem α-Isopropyliden- und α-Ethyliden-substituierte α-Sulfonylether nach Peterson hergestellt. Über Besonderheiten bei der Synthese sowie über die Zuordnung der 1H-NMR-Signale mittels Verschiebungsreagenzien wird berichtet.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1975 (1975), S. 1484-1498 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Sulfonyl Ethers IX. - Enol Ethers of α-Ketosulfones from Carbonyl Olefination with Anions of α-Alkoxy α-Sulfonyl KetonesAnions of α-acylated a-sulfonyl ethers 1 condense with reactive aldehydes 2 (without α-hydro-gen) yielding enol ethers of hypothetic α-ketosulfones. The acyl groups of the anionic components and the aldehyde oxygens of the carbonyl components are split off together as carboxylates in a fragmentation step. Depending on the nature of the aldehyde, E-isomers and mixtures of E,Z-isomers are formed; however 2-isomers also arise stereospecifically which with one exception quantitatively rearrange by proton catalysis yielding thermodynamically more stable E-isomers. NOE measurements are used to determine the structure.
    Notes: Anionen von α-Sulfonyläthern 1 kondensieren mit reaktiven Aldehyden 2 (ohne α-ständigen Wasserstoff) zu Enoläthern hypothetischer α-Ketosulfone. Die Acylgruppe der Anionkomponente und der Aldehydsauerstoff der Carbonylkomponente werden dabei gemeinsam im Sinne einer Fragmentierung als Carboxylat abgespalten. - In Abhängigkeit vom Aldehyd entstehen reine E-Isomere und E,Z-Isomerengemische, jedoch auch stereospezifisch Z-Isomere, die sich zum Teil durch Protonenkatalyse quantitativ in die thermodynamisch stabileren E-Isomere umlagern. Die Zuordnungen erfolgen aufgrund von NOE-Messungen.
    Additional Material: 7 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1713-1726 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Catalyzed Insertion Reactions into Alcoholic OH-Groups by Diazo Derivatives of Compounds with Activated Methylene GroupsA preparatively facile method is described for decomposing the diazo compounds 6, 9, and 12, which are prepared from the carbonyl- and sulfonyl-activated methylene compounds 5, 8, and 11 in aliphatic alcohols with OH-insertion. The yields of insertion products 7, 10, and 13 becomes greater and greater compared with those of the products of a preceding Wolff rearrangement the less the carbeniate electron pair of the diazo compound is delocalized as a consequence of mesomerism. cr-Methoxy β-diketones 13 are therefore better prepared by an improved ester condensation.
    Notes: Für die Zersetzung der Diazoverbindungen 6, 9 und 12, die aus den carbonyl- und sulfonylaktivierten Methylenverbindungen 5, 8 und 11 erhalten werden, in aliphatischen Alkoholen unter OH-Insertion wird eine präparativ einfache Methode beschrieben. Die Ausbeuten an Insertionsprodukten 7, 10 und 13 dominieren um so mehr über die an Folgeprodukten einer Wolff-Umlagerung, je weniger das Carbeniat-Elektronenpaar der Diazoverbindung infolge Mesomerie delokalisiert ist. Die cr-Methoxy-β-diketone 13 werden deshalb günstiger über eine verbesserte Esterkondensation hergestellt.
    Additional Material: 4 Tab.
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