Copper(I)-Catalyzed Chemoselective Reduction of Benzofuran-2-yl Ketones to Alcohols with B2pin2 via a Domino-Borylation-Protodeboronation Strategy.

A novel copper(I)-catalyzed chemoselective reduction of the carbonyls of benzofuran-2-yl ketones over furan rings with B2pin2 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.