Diboron-Assisted Palladium-Catalyzed Transfer Hydrogenation of <i>N</i>‑Heteroaromatics with Water as Hydrogen Donor and Solvent

A Pd-catalyzed transfer hydrogenation of various <i>N</i>-heteroaromatic compounds with B₂pin₂ as a mediator and environmentally benign water as both solvent and hydrogen donor has been disclosed. This reaction proceeded under ambient temperature with a broad range of <i>N</i>-heteroaromatic compounds among which imidazo­[1,2-<i>a</i>]­pyridine derivatives were for the first time selectively reduced to 5,6,7,8-tetrahydroimidazo­[1,2-<i>a</i>]­pyridines, which are the core structural motifs of an inhibitor of human <i>O</i>-GlcNAcase. Mechanistic studies suggested that the new protons in products are from water and Pd–H might be the key intermediate with B₂pin₂ as the H₂O activator

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