Direct Photoredox-Catalyzed Reductive Difluoromethylation of Electron-Deficient Alkenes

Photoredox-catalyzed reductive difluoromethylation of electron-deficient alkenes was achieved in one step under tin-free, mild and neutral conditions. This protocol affords a facile method to introduce RCF2 (R=H, Ph, Me, and CH2N3) groups at sites β to electron-withdrawing groups. It was found that TTMS (tris(trimethylsilyl)silane) served nicely as both the H-atom donor and the electron donor in the catalytic cycle. Experimental and DFT computational results provided evidence that RCF2 (R=H, Ph, Me) radicals are nucleophilic in nature.