Synthesis of Dihydropyrrole and Pyrrole Derivatives by Radical Cyclization of (gamma),(delta)-Unsaturated Ketone O-Acetyloximes

Treatment of (gamma),(delta)-unsaturated ketone O-acetyloximes with a catalytic amount of 1,5-naphthalenediol or hydroquinone, acetic acid, and 1,4cyclohexadiene affords various dihydropyrrole and pyrrole derivatives via radical cyclization induced by one-electron reduction of the oximes.