A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids

A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH₄ to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp³ carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.