Visible light induced Barton decarboxylation free of radical initiators

Herein, a novel protocol for visible light induced decarboxylation was reported. The method avoids the addition of radical initiators. A series of primary, secondary, and tertiary redox-active esters underwent decarboxylation efficiently, as well as amino acid and peptide derivatives. Many natural products and drug molecules containing carboxyl groups can also be transformed well. The method has mild reaction conditions, wide substrate scope, satisfactory functional group compatibility with good to excellent yields. The preliminary mechanism studies suggested that tris(trimethylsilyl)silane((TMS)3SiH) acts not only as a hydrogen source, but also as an electron donor to form electron donor-acceptor (EDA) complex with redox-active esters, and the reaction involves the radical process.