Divergent and Stereoselective Synthesis of Enamides via Visible Light-Driven Ligand-to-Metal Charge Transfer of Copper Catalyst

Abstract

We herein report the divergent and stereoselective synthesis of enamides based on a hydrogen atom transfer (HAT) process coordinating with ligand-to-metal charge transfer (LMCT) and single-electron transfer (SET) processes using a copper catalyst. The key to success in furnishing the reaction was the formation of an acyl radical via LMCT and HAT processes, which can also regenerate the active Cu(II) species to realize the catalytic cycle of copper. This approach exhibits substrate-controlled chemoselectivity and stereoselectivity as well as excellent functional group tolerance, which was applicable to the late-stage functionalization of pharmaceuticals, such as ibuprofen, flurbiprofen, naproxen, and carbamazepine.