Cr-Catalyzed Difluoromethylation of α-Trifluoromethyl Alkenes for Modular Synthesis of Polyfluorinated Compounds

Abstract

We report a chromium-catalyzed allylic difluoromethylation of α-trifluoromethyl alkenes, allowing one-step access to polyfluorinated compounds characteristic with both gemdifluoroalkene and difluoromethyl groups. The reaction employs inexpensive chromium as the catalyst, commercially available and bench-stable difluoromethyl 2-pyridyl sulfone as difluoromethylation reagent, proceeding under mild conditions with broad substrate scope. The mechanism studies indicate the involvement of radical species in this chromium-catalyzed difluoromethylation process. Gram-scale reaction and the late-stage diversification of complex molecules were successfully executed.