Lewis Acid Activation of Fragment-Coupling Reactions of Tertiary Carbon Radicals Promoted by Visible-Light Irradiation of EDA Complexes

Abstract

The addition of tertiary carbon radicals generated from <i>N</i>-(acyloxy)phthalimide esters to cyclic α,β-unsaturated ketones and lactones is markedly enhanced by the addition of substoichiometric amounts of a Ln(OTf)₃. The reaction is accomplished by irradiation with visible light in the absence of a photosensitizer and is suggested to proceed by excitation of a ternary electron donor-acceptor complex between the NHPI ester, Hantzsch ester, and a Ln(OTf)₃.