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

The 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.