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

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. Efficient palladium-catalyzed regioselective vinylic C-H polyfluoroarylation of gem-disubstituted ethylenes with polyfluoroarenes was realized via an aryl to vinyl 1,4-palladium migration process to access various polyfluorinated triarylethenes.