Direct electrochemical defluorinative carboxylation of α-CF3 alkenes with carbon dioxide.

An unprecedented γ-carboxylation of α-CF3 alkenes with CO2 is reported. This approach constitutes a rare example of using electrochemical methods to achieve regioselectivity complementary to conventional metal catalysis. Accordingly, using platinum plate as both a working cathode and a nonsacrificial anode in a user-friendly undivided cell under constant current conditions, the γ-carboxylation provides efficient access to vinylacetic acids bearing a gem-difluoroalkene moiety from a broad range of substrates. The synthetic utility is further demonstrated by gram-scale synthesis and elaboration to several value-added products. Cyclic voltammetry and density functional theory calculations were performed to provide mechanistic insights into the reaction.