Photoinduced catalytical reduction of carbonyl compounds using water as a hydrogen source

Abstract

An efficient light-driven methodology to synthesize alcohols is presented through reduction of carbonyl compounds by a photoinduced Ir/PPh₃/H₂O system. Water, as a valuable and readily available resource, is introduced as the major hydrogen source in this transfer hydrogenation reaction, while PPh₃ is employed as a sacrificial reductant. Aryl/alkyl carbonyl compounds and aryl imines are tolerated in this methodology, producing several primary alcohols and secondary alcohols as well as secondary amines in the presence of thiophenol as a hydrogen atom transfer catalyst. Bimolecular reductive coupling reaction of carbonyl compounds has also been realized in the absence of thiophenol, generating various symmetrical pinacols as products.