Stereo- and Enantioselective Benzylic C–H Alkenylation via Photoredox/Nickel Dual Catalysis

A stereo- and enantioselective benzylic C–H alkenylation via photoredox/nickel catalysis is reported. Readily available alkylbenzenes and alkenyl bromides including complicated molecules undergo this cross-coupling reaction smoothly to afford chiral allylic compounds in up to 93% ee and >20/1 E/Z ratio under mild reaction conditions with good functional group tolerance. A triplet-energy-transfer-inhibiting strategy is developed for the stereoselective synthesis of alkenes under visible-light photocatalysis. The coordination pattern of nickel with chiral bis-imidazoline ligand has been illustrated based on nonlinear effect experiments and X-ray diffraction.