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  • 1
    Electronic Resource
    Electronic Resource
    Zur Regio- und Stereoselektivität neuer thermischer [3 + 2]-Cycloadditionen mesoionischer 1,3-Oxathiol-4-one an Alkine und Alkene (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2317-2338 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Regio- and Stereoselectivity of Novel Thermal [3 + 2] Cycloaddition Reactions of Mesonionic 1,3-Oxathiol-4-ones to Alkynes and AlkenesAs potential carbonyl ylides, the 1,3-oxathiolyium-4-olates 1c or 1d combine with dibenzoylacetylene or 1-(diethylamino)-1-propyne via nonisolable [3 + 2] primary adducts of type 2, which release COS to give the furan derivatives 3a or b, respectively. On the other hand, some representative of 1 reacts with symmetrically and unsymmetrically substituted olefinic substrates with regio- and/or stereoselective formation of the isolable [3 + 2] primary adducts 4-16. In the example of the reactions of 1c with trans- and cis-cyclooctene, the stereospecificities and the competition constant are determined. Furthermore, the thermolyses of the cycloadducts 4b,5,6, and 7a,b are investigated. The addition directions, derived from the FMO and PMO theory, are compared with the experimentally realized regiochemistry.
    Notes: Als potentielle Carbonyl-ylide vereinigen sich die 1,3-Oxathiolylium-4-olate 1c oder 1d mit Dibenzoylacetylen oder 1-(Diethylamino)-1-propin über nicht isolierbare [3 + 2]-Primäraddukte vom Typ 2 unter COS-Abspaltung zu Furan-Derivaten 3a bzw. b. Demgegenüber reagieren einige Vertreter von 1 mit symmetrisch und unsymmetrisch substituierten olefinischen Substraten regio- und/oder stereoselektiv zu isolierbaren [3 + 2]-Primäraddukten 4-16. Am Beispiel der Umsetzung von 1c mit trans- und cis-Cycloocten werden die Stereospezifitäten und die Konkurrenzkonstante ermittelt. Weiterhin werden die Thermolysen der Cycloaddukte 4b, 5, 6 und 7a,b untersucht. Die aus der FMO- und PMO-Theorie abgeleiteten Additionsrichtungen werden mit der experimentell realisierten Regiochemie verglichen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190723
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  • 2
    Electronic Resource
    Electronic Resource
    Magnesium Adducts of Substituted Anthracenes - Preparation and Properties (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1529-1536 
    Details
    ISSN: 0009-2940
    Keywords: Magnesium anthracenes, substituted, reactions of, spectra of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Methyl-, 1,4-dimethyl-, 9-methyl-, 9-ethyl-, 9,10-dimethyl-, and 9-phenylanthracene (1a-f) react with magnesium in THF at room temperature to afford the corresponding substituted magnesium anthracenes 2a-i. 9,10-Diphenylanthracene (1g), however, reacts with magnesium under the same conditions to produce the deep-blue magnesium bis(9,10-diphenylanthracenide) · 6 THF (4g). Upon heating to 60°C in THF, 4g reversibly dissociated to give magnesium 9,10-diphenylanthracene · 3 THF (2g) and 1g, while prolonged heating at 60°C causes decomposition of 2g to active magnesium (Mg*) and 1g. In THF 2a-c, e, and f exhibit temperature-dependent equilibria with 1a-c, e, and f and magnesium. Compared with magnesium anthracene · 3 THF (2), these equilibria are strongly shifted toward substituted anthracenes and magnesium, and only at 0°C high conversions are achieved. The magnesium exchange between 2 and the substituted anthracenes 1a,b, and f in THF has been experimentally verified. 2a,e, and f react with organic halides in the same way as 2, however, in the case of allyl, propargyl, and benzyl chloride the yields of Grignard compounds are lower than for 2; with bromobenzene, the tendency for the radical transfer reaction is stronger than for 2. Magnesium 9,10-dimethylanthracene (2e) reacts with ethyl acetate to give the bicyclic tertiary alcohol 9 by an intramolecular C-C coupling reaction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230713
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  • 3
    Electronic Resource
    Electronic Resource
    Darstellung und Charakterisierung von Anthrylenmagnesium-Innerkomplexen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 225-237 
    Details
    ISSN: 0009-2940
    Keywords: Anthracene derivatives ; Magnesium anthracene inner complexes ; 13C CP/MAS NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Characterization of Inner Complexes of AnthrylenemagnesiumAnthracene derivatives containing ether or amino groups in 9- or 9,10-position (1 - 10) react with magnesium to form new magnesium anthracene inner complexes (11 - 20). These complexes as well as their organic starting materials have been extensively characterized by spectroscopy and chemical means. It was found that solvent ligands which are present in all magnesium anthracene complexes known to date can be partially or totally replaced by inner complexation. For some of the new magnesium anthracene inner complexes the complex formation rates have been determined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260131
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  • 4
    Electronic Resource
    Electronic Resource
    Neue Magnesiumanthracen-Komplexe durch Ligandenaustausch (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 33-37 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Magnesium Anthracene Complexes by Ligand ExchangeComplexed tetrahydrofuran in magnesium anthracene · 3 THF (1) is displaced by mono-, bi-, and tridentate ligands L (L = dioxane, 1,2-dimethoxyethane, ethylbis(2-methoxyethyl)amine, pentamethyldiethylenetriamine, 1,4,7-trimethyl-1,4,7-triazacyclononane) affording the magnesium anthracene complexes C14H10Mg · n L (2a-e); upon reaction of 1 with tetramethylethylenediamine (TMEDA) magnesium anthrancene · THF · TMEDA is formed. The new magnesium complexes 2a-e are protolysed to Mg2+, 9,10-dihydroanthracene, and L. In solvents of low Lewis basicity (ether, hydrocarbons) 1 decomposes, probably via magnesium anthracene · 2 THF, to active magnesium, anthracene, and THF. A similar behaviour in toluene is displayed also by magnesium butadiene · 2 THF.
    Notes: Das in Magnesiumanthracen · 3 THF (1) komplexgebundene THF kann durch ein-, zwei- und dreizähnige Liganden L unter Bildung der Magnesiumanthracen-Komplexe C14H10Mg · n L (2a-e, L = Dioxan, 1,2-Dimethoxyethan, Ethylbis(2-methoxyethyl)amin, Pentamethyldiethylentriamin, 1,4,7-Trimethyl-1,4,7-triazacyclononan) verdrängt werden; bei der Reaktion von 1 mit Tetramethylethylendiamin (TMEDA) entsteht Magnesiumanthacen · THF · TMEDA. Die neuen Mg-Komplexe 2a-e ergeben bei der Protolyse Mg2-, 9,10-Dihydroanthracen und L. In Lösungsmitteln geringer Lewis-Basizität (Ether, Kohlenwasserstoffe) zersetzt sich 1, wahrscheinlich über die Zwischenstufe von Magnesiumanthracen · 2 THF, zu aktivem Magnesium, Anthracen und THF. ähnlich verhält sich auch Magnesiumbutadien · 2 THF in Toluol.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210107
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  • 5
    Electronic Resource
    Electronic Resource
    Use of Magnesium Anthracene·3THF in Synthesis: Generation of Grignard Compounds and Other Reactions with Organic Halides (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1507-1516 
    Details
    ISSN: 0009-2940
    Keywords: Magnesium anthracene ; Grignard compounds ; Magnesium, active ; Radical transfer reaction ; Allenylmagnesium chloride ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The course (a), (b), (c) (Scheme 1) of the reaction of magnesium anthracene·3THF (1) with organic halides (RX) is dependent on the nature of RX. With alkyl halides in THF 1 reacts as a nucleophile, whereby primary as well as secondary alkyl halides produce dialkyldihydroanthracenes (4-4′′) and tertiary alkyl halides yield primarily monoalkyl-substituted dihydroanthracenes (2, 2′). With bromo- and iodobenzene in THF 1 reacts predominantly as a radical with H atom abstraction from the solvent affording benzene and 9. The formation of Grignard compounds (5) and anthracene (6), originating from primary and secondary alkyl and aryl halides and 1 in toluene or ether at elevated temperatures, is not caused by the reaction of 1 but by the “active magnesium” (Mg*) formed by decomposition of 1 in these solvents. In contrast, allyl, propargyl, and benzyl halides react with 1 independently of the solvent under mild conditions to produce 5 and 6. Allyl- and the difficultly accessible allenylmagnesium chloride can be prepared in THF at -78 and 0°C, respectively, from the corresponding halides and ordinary Mg powder via catalytic amounts of 1.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230711
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese und physikalische Eigenschaften stabiler 1,3-Oxathiolylium-4-olate (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2308-2316 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Physical Properties of Stable 1,3-Oxathiolylium-4-olatesThe synthesis and physical properties as well as some data, calculated with the MNDO method, of the title compounds of type 5a-e and 8, which belong to the class of the mesoionic 6π hetarenes, are described.
    Notes: Die Synthese und physikalischen Eigenschaften sowie einige mit dem MNDO-Verfahren berechnete Daten der Titelverbindungen vom Typ 5a-e und 8, die zur Klasse der mesoionischen 6π-Hetarene zählen, werden beschrieben.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190722
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