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  • 1
    Electronic Resource
    Electronic Resource
    Zur Reaktion von Halogen(trimethylsilyl)benzolen mit Elektrophilen und Basen - Carbodesilylierung und Eliminierung als Konkurrenzreaktionen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2113-2118 
    Details
    ISSN: 0009-2940
    Keywords: Halo(trimethylsilyl)benzenes, carbodesilylation and elimination of ; Carbodesilylation ; Elimination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Halo(trimethylsilyl)benzenes with Electrophiles and Bases - Carbodestlylation and Elimination as Competitive ReactionsElimination to dehydrobenzenes takes place as competitive reaction in the base-catalyzed carbodesilylation of 1-halo-2-(trimethylsilyl)benzenes 1 with carbonyl compounds 2 in the presence of furans 3, 6. Elimination is preferred with increasing leaving tendency of the halides (I 〉 Br 〉 〉 Cl 〉 〉 F) and with decreasing reactivity of the carbonyl compounds. Exclusive elimination to 1,2-didehydrobenzenes - which are trapped with furans - occurs in the reaction when no electrophiles are present.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240938
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  • 2
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der Carbodesilylierung 4- bzw. 5-substituierter 2-(Trimethylsilyl)pyridine mit Benzaldehyd (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1131-1140 
    Details
    ISSN: 0009-2940
    Keywords: Pyridines, substituted 2-(trimethylsilyl)-, synthesis of, carbodesilylation of ; Carbodesilylation ; Rate constants ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Mechanism of the Carbodesilylation of 4- or 5-Substituted 2-(Trimethylsilyl)pyridinesAn “ylide mechanism” is proposed for the carbodesilylation of 2-(trimethylsilyl)pyridines with benzaldehyde. In contrast, 3-and 4-(trimethylsilyl)pyridines, react only in the presence of a base catalyst via pyridyl anions with electrophiles. The rates of the uncatalyzed carbodesilylation reactions of 4-substituted 2-(trimethylsilyl)pyridines 2 with benzaldehyde correlate very well with the resonance parameters of the substituents ρRO, whereas the rates of 5-substituted 2-(trimethylsilyl)pyridines 7 correlate with the inductive substituent parameters ρI in the Taft equation. This is to our knowledge the first direct determination of the resonance parameters ρRO.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250524
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  • 3
    Electronic Resource
    Electronic Resource
    Carbodesilylierung von (Trimethylsilyl)imidazolen und -pyrazolen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1639-1650 
    Details
    ISSN: 0009-2940
    Keywords: Imidazoles, (trimethylsilyl) ; carbodesilylation of ; Pyrazoles, (trimethylsilyl) ; carbodesilylation of ; Carbodesilylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbodesilylation of (Trimethylsilyl)imidazoles and -pyrazolesThe preparation of the 1-methyl(trimethylsilyl) (TMS)-substituted imidazoles 3a, 4a, 8, 9, and 11a by silylation of the corresponding metallated imidazoles is described. Carbodesilylation of 3 with aldehydes or carboxylic halogenides occurs selectively in 2-position. In the presence of a strong base (CsF) the reactivity against carbon electrophiles correlates well with the stability of the imidazolyl anions; regioselective carbodesilylation in 2-, 5-, or 4-position of the twofold TMS-substituted imidazoles 3a and 9 therefore is possible, which allows the synthesis of a great variety of hydroxyalkyl-substituted imidazoles and of acylimidazoles. By using the dimethylsulfamoyl substituent as an N-protecting group, the N- unsubstituted 5-benzoylimidazole (26) as well as the comparable 5-benzoyl-pyrazole (30b) and 5-(hydroxyphenylmethyl)-pyrazole (30a) are accessible.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240727
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