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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 849-853 
    ISSN: 0947-3440
    Keywords: Organofluorine compounds ; 1-Fluoroalkyl esters ; 2-Fluoroalkyl esters ; Ene esters ; Diene esters ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-fluoroalkyl esters (1-4) of carboxylic acids are readily accessible by the base-catalyzed acylation of fluorohydrines. A two-step procedure is required to prepare the 1-fluoroalkyl esters (10-14, 16): conversion of alk-1-enyl carboxylates („ene esters“) into the 2-bromo-1-fluoroalkyl esters 5-9, 15, 17-19 by simultaneous treatment with N-bromosuccinimide and hydrogen fluoride followed by the reductive replacement of bromine by tributyltin hydride. Alka-1,3-dienyl carboxylates („diene esters“) undergo 1,4-addition of bromine and fluorine. The resulting 4-bromo-1-fluoroalk-2-enyl carboxylates 20-25 undergo a substitution reaction with sodium benzenesulfinate to afford the sulfones 26-28 or oxidation with dimethyl sulfoxide to yield the 4-oxo derivatives 29-30.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 83-88 
    ISSN: 0009-2940
    Keywords: Torsional (Z/E) isomerization ; Selectivity, regio- and stereo- ; Allylsilanes ; Allylic oxidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alk-2-enylpotassium compounds having the endo conformation are synthetically very valuable precursors of (Z)-olefinic derivatives substituted at the outward allylic position. They may be generated by „stereoconservative‘ metalation of the readily available (Z)-alk-2-enes by using the superbasic mixture of butyllithium and potassium tert-butoxide or by metalation under similar conditions of stereorandom mixtures of alk-2-enes or alk-1-enes followed by torsional isomerization of the concomitantly formed exo conformers to the thermodynamically more stable endo species. The principal factors that dictate the rate and the extent of the endo/exo equilibration are the substrate geometry, the solvent, the temperature, the reagent stoichiometry, and catalysis.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 335-340 
    ISSN: 0009-2940
    Keywords: Allylsilanes ; Superbases ; Metalations ; Stereoselectivity ; Cyclizations ; Silicon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When treated with two equivalents of a butyllithium/potassium tert-butoxide mixture, terminal olefins carrying unprotected hydroxy or carboxy groups generate allylmetal intermediates which can be trapped with chlorotrimethylsilane to afford functionalized (Z)-2-alkenyltrimethylsilanes. One equivalent of the superbasic reagent suffices if the unsaturated alcohols are first protected as acetals before being subjected to the metalation/silylation/hydrolysis sequence.
    Type of Medium: Electronic Resource
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