Solvent-Controllable C-F Bond Activation for Masked Formylation of α-Trifluoromethyl Alkenes via Organo-Photoredox Catalysis.

A solvent-controllable organo-photoredox-catalyzed C-F bond activation for masked formylation of α-trifluoromethyl alkenes with low-priced 1,3-dioxolane as masked formyl radical equivalent has been described. Consequently, a diversity of masked formylated gem-difluoroalkenes and monofluoroalkenes are constructed in moderate to high yields. This approach merits readily available starting materials, mild reaction conditions, and broad substrate scope. The feasibility of this approach has been highlighted by the one-pot masked formylation/hydrolysis sequence to form γ,γ-difluoroallylic aldehydes and late-stage modification of pharmaceutical and natural product derivatives.