Visible-Light-Promoted Copper-Catalyzed Etherification of Aryl Bromides via Energy Transfer

A visible-light-promoted copper-catalyzed C-O coupling reaction of alcohols with aryl bromides using eosin Y as the photosensitizer has been developed, in which energy transfer (EnT) from eosin Y to the copper complex of the oxalamide ligand generates an excited-state copper complex that facilitates oxidative addition of aryl bromides. This mild method enables the efficient synthesis of alkyl aryl ethers and biaryl ethers with a broad substrate scope and excellent tolerance of sensitive functional groups at room temperature.