Regioselective polyfluoroarylation of alkenyl C–H bonds via aryl to vinyl 1,4-palladium migration

Abstract

Efficient palladium-catalyzed regioselective vinylic C–H polyfluoroarylation of gem-disubstituted ethylenes with polyfluoroarenes was realized to access a variety of polyfluorinated triarylethenes. An aryl to vinyl 1,4-palladium migration is proposed to achieve high regio- and stereoselectivities for the target products. This strategy features broad substrate scopes and good functional group tolerance. Mechanistic studies have suggested that a protonation–deprotonation process reversibly occurs between a five-membered palladacycle and the vinyl–palladium intermediates, and aromatic C–H cleavage of polyfluoroarenes contributes to the rate-limiting step in the overall catalytic cycle.