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  • Stereochemistry and some kinetic aspects of fluorination of phenyl-substituted alkenes with ▫$selectfluor^TM$▫ reagent ▫$F-TEDA-BF_4$▫
    Stavber, Stojan ; Sotler-Pečan, Tjaša ; Zupan, Marko, 1947-
    Reactions of phenyl-substituted alkenes with ▫$Selectfluor^{TM}$▫ fluorinating reagent ▫$F-TEDA-BF_4$▫ in the presence of various alcohols resulted in the formation of vinical fluoroalkoxy adducts ... with Markovnikov type of regioselectvity. The stereochemistry of the fluoro-methoxylation addition reaction was found to be slightly syn predominant in the case of (Z)-stilbene, indene, and dibenzosuberone, while equal amounts of both diastreoisomers were formed in the case of (E)-1-phenyl-1-propene and acenaphthylene. In the phenyl-substituted benzocyclene series the stereochemistry of fluoroalkoxylation was found to be dependent on ring size and on the structure of the alcohol. The resulting vicinal fluoroalkoxy adducts were transformed by heating in aqueous HBr to 2-fluoro-phenylbenzocylenes. Correlation of the logarthms of relative rates of fluoro-methoxylation reactions in a series of ten ▫$\alpha-phenyl$▫ and ▫$\alpha, \alpha-diphenyl$▫ acyclic and cyclic alkenes with the ionization potentials of these alkenes resulted in a linear relationship with a slope of -2.75. Correlation of ▫$log k_rel$▫ for the present reaction with those for the reaction with those for the reaction of the same alkenes with ▫$CsSO_4F$▫ or ▫$XeF_2$▫ yielded exellent linearity for the pair ▫$F-TEDA/XeF_2$▫. The Hammett correlation analysis of the reaction of substituted 1,1-diphenylethenes with F-TEDA in MeCN/MeOH solvent gave the reaction constant ▫$\rho^+$▫ of -1.42, so indicating a moderate electron deficiency on the reactive center in the rate-determining step of the reaction.
    Vir: Bulletin of the Chemical Society of Japan. - ISSN 0009-2673 (Vol. 69, no. 1, 1996, str. 169-175)
    Vrsta gradiva - članek, sestavni del
    Leto - 1996
    Jezik - angleški
    COBISS.SI-ID - 3918631

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