Synthesis of 4,4-Difluoroalkenes by Coupling of α-Substituted α,α-Difluoromethyl Halides with Allyl Sulfones under Photoredox Catalyzed Conditions.

Photoredox-catalyzed allylation of α-gem-difluorinated organohalides with allyl sulfones proceeded smoothly under visible light irradiation to give 4,4-difluoroalkenes in good yields. In the presence of catalytic Ru(bpy)3Cl2, Hantzsch ester, and diisopropylethylamine, the reaction was complete within 2 h. Using the same methodology, three-component cascade reactions to give 6,6-difluoroalkenes were carried out successfully.