Copper(I)-Catalyzed Chemoselective Reduction of Benzofuran-2-y1 Ketones to Alcohols with B2pin2 via a Domino-BorylationProtodeboronation Strategy

A novel copper(I)-catalyzed chemoselective reduction of the carbonyls of benzofuran-211 ketones over furan rings with B(2)pin(2) has been developed. This reaction proceeded under mild conditions. High valuable secondary alcohol derivatives of benzofurans were obtained in good to excellent yields with a broad substrate scope. The mechanistic studies suggested that a domino-borylation-protodeboronation pathway was involved in this reaction.