Visible-light-enabled denitrative carboxylation of β-nitrostyrenes: a direct photocatalytic approach to cinnamic acids

Abstract

The first workable application of β-nitrostyrenes and CBr₄ as coupling partners for a highly stereoselective synthesis of (E)-cinnamic acids under visible light photoredox catalysis is reported. The reaction involves a radical denitrative tribromomethylation/hydrolysis cascade to afford (E)-cinnamic acids in excellent yields at room temperature in a one-pot procedure. Moreover, the implementation of visible light as a clean and inexpensive energy source and CBr₄ as the latent source of carboxylic groups makes the protocol reconcilable with the present day scenario of organic synthesis.