Activation of 1,1-Difluoro-1-alkenes with a Transition-Metal Complex: Palladium(II)-Catalyzed Friedel–Crafts-Type Cyclization of 4,4-(Difluorohomoallyl)arenes

Abstract

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.OEt2, the cyclization was effected by a catalytic amount of the palladium without its reoxidation.