Dual Photoredox/Palladium Catalysis Enabled Enantioselective Heck/Reductive Allylic Homocoupling Reaction

The merger of palladium‐catalyzed Tsuji‐Trost reactions with photochemical radical chemistry represents a cutting‐edge field in transition metal catalysis. We report a photochemical palladium‐catalyzed enantioselective Heck/reductive allylic homocoupling reaction of 1,3‐dienes. The transformation has a wide substrate scope and good functional group tolerance, providing a platform to synthesize optically pure chiral 1,5‐dienes bearing 1,8‐stereocenters. The reaction initiates with a Heck‐type addition to generate a π‐allyl‐PdII species, followed by a photoredox process or ligand‐to‐metal charge transfer (LMCT) to generate an allylic radical, which undergoes homocoupling to give the final product.