Palladium-Catalyzed gem-Difluoroallylation Reaction between Aryltributyltin and Bromodifluoromethylated Alkenes

A robust Stille gem-difluoroallylation of arylstannanes with 3-bromo-3,3-difluoropropenes has been established. The catalyst was found to exert critical effect on the reaction chemoselectivity. By using Pd­(OH)2/C as the catalyst, a series of 3-(hetero)­aryl/vinyl-3,3-difluoropropenes were obtained in high efficiency with α-substitution regioselectivity. The reaction has a broad substrate scope, and various substitution patterns were well tolerated in both substrates. Notably, the reaction can be easily extended to late-stage gem-difluoroallylation of many bioactive molecules with good chemoselectivity.