Iminyl‐Radicals by Oxidation of α‐Imino‐oxy Acids: Photoredox‐Neutral Alkene Carboimination for the Synthesis of Pyrrolines

Abstract

AbstractThe visible‐light‐promoted decarboxylation of α‐imino‐oxy propionic acids for the generation of iminyl radicals has been accomplished through the use of Ir(dFCF3ppy)2(dtbbpy)PF6 as a photoredox catalyst. Different from visible‐light‐promoted homolysis and single‐electron reduction of oxime derivatives, this strategy provides a novel catalytic cycle for alkene carboimination through a sequence comprising N‐radical generation, iminyl radical cyclization, intermolecular conjugate addition to a Michael acceptor, and single‐electron reduction to afford various pyrroline derivatives in an overall redox‐neutral process. The indolizidine alkaloid skeleton could be easily constructed from a pyrroline derivative prepared by this synthetic method.