Visible-Light-Mediated β-C-H gem-Difluoroallylation of Aldehydes and Cyclic Ketones through C-F Bond Cleavage of 1-Trifluoromethyl Alkenes.

gem-Difluoroalkene bearing a carbonyl group is a challenging target to synthesize by conventional methods. Herein we report a mild and concise route to access the target compounds through the visible-light-mediated direct β-C-H gem-difluoroallylation of aliphatic aldehydes and cyclic ketones. Upon a synergistic combination of photoredox catalysis and organocatalysis, various α-CF3 alkenes were employed as the gem-difluoroallylation reagents via the C-F bond cleavage.