A silver-catalyzed decarboxylative coupling of readily available oxamic acids with styrenes to the direct synthesis of E-cinnamamides has been developed. The reaction pathway was studied and proven to be different from known procedures.

Abstract

A silver-catalyzed decarboxylative coupling of oxamic acids with styrenes has been developed to produce E-cinnamamides. Oxamic acids act as efficient precursors for carbamoy radicals. Based on the mechanistic experiments and intermediate analysis, the proposed mechanism involves radical addition to styrenes, followed by oxidation and solvent participation, ultimately leading to the formation of cinnamamides which is different from the reported cases.