Visible-Light-Enabled Decarboxylative Mono- and Difluoromethylation of Cinnamic Acids under Metal-Free Conditions.

Several new mono- and difluoromethylation reactions of cinnamic acids using an Eosin Y catalytic system are reported. An efficient alkene fluoromethylation of α,β-unsaturated carboxylic acids was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. A mechanism that involves a radical process is proposed for this reaction.