Activation of 1,1-Difluoro-1-alkenes with a Transition-Metal Complex: Palladium(II)-Catalyzed Friedel–Crafts-Type Cyclization of 4,4-(Difluorohomoallyl)arenes
摘要:
Cationic palladium(II) ([Pd(MeCN)(4)](BF4)(2)) provides the first transition-metal-catalyzed method for electrophilic activation of electron-deficient 1,1-difluoro-1-alkenes, which allows their Friedel-Crafts-type cyclization with an intramolecular aryl group via a Wacker-type process. By using BF3 center dot OEt2, the cyclization was effected by a catalytic amount of the palladium without its reoxidation.
Activation of 1,1-Difluoro-1-alkenes with a Transition-Metal Complex: Palladium(II)-Catalyzed Friedel–Crafts-Type Cyclization of 4,4-(Difluorohomoallyl)arenes
作者:Misaki Yokota、Daishi Fujita、Junji Ichikawa
DOI:10.1021/ol702279w
日期:2007.10.1
Cationic palladium(II) ([Pd(MeCN)(4)](BF4)(2)) provides the first transition-metal-catalyzed method for electrophilic activation of electron-deficient 1,1-difluoro-1-alkenes, which allows their Friedel-Crafts-type cyclization with an intramolecular aryl group via a Wacker-type process. By using BF3 center dot OEt2, the cyclization was effected by a catalytic amount of the palladium without its reoxidation.
Silylium Ion Initiated Intramolecular Friedel–Crafts-Type Cyclization of 1,1-Difluoroalkenes with Subsequent Hydrodefluorination of C(sp3)–F Bonds
作者:Avijit Roy、Haopeng Gao、Martin Oestreich、Hendrik F. T. Klare
DOI:10.1055/a-2009-8114
日期:——
reaction is presumed to be initiated by a preferential electrophilic silylation of the carbon–carbon double bond over the activation of one of the vinylic C(sp2)–Fbonds. Subsequent cyclization followed by hydrodefluorination of the resulting C(sp3)–Fbonds leads to the final product. The resulting tetraline derivatives were obtained in moderate to good yields. Distinct from earlier reports, the reaction