Oxidant‐Controlled Divergent Syntheses of Pyrazoles and Pyrroles by Copper(I)‐Catalyzed Oxidative Coupling of β‐Enamino Esters

Abstract Copper(I)‐catalyzed oxidative annulations of β‐enamino esters with oxidant dependence are disclosed. These reactions offer divergent syntheses of fully substituted pyrazoles and pyrroles from a common enamine substrate through sequential C−C and N−N or C−N bond‐forming reactions in the presence of nitriles as reagent or cosolvent. A mechanism involving radical intermediates generated by single‐electron transfer (SET) is proposed for both processes.