Visible-Light-Mediated Hydroacylation of Azobenzenes with α-Keto Acids.

A visible-light-mediated protocol for the hydroacylation of azobenzenes with α-keto acids has been developed. In the absence of any catalyst or additive, decarboxylative hydroacylation proceeded smoothly under visible-light irradiation at room temperature. A wide range of azobenzenes and α-keto acids were well-tolerated and afforded hydroacylation products in high to excellent yields. Preliminary investigations indicated that photoactive azobenzenes absorb visible light to enable the transformation.