Additive-Free Radical Cascade Reaction of Oxime Esters: Synthesis of Pyrroline-Functionalized Phenanthridines

A variety of dihydropyrrole-functionalized phenanthridines were efficiently synthesized by the metal-free, radical cascade cyclization reaction of 2-isocyanobiphenyls with γ,δ-unsaturated oxime esters. The C–N/C–C/C–C bonds were formed via the oil bath method in a one-pot procedure with broad substrate applicability. The radical process was supported by kinetic isotope effect studies and radical inhibition studies.