Iron-Catalyzed Double Annulation of O-Acyl Oximes with Fumaronitrile for the Synthesis of 4-Cyano-7-azaindoles

An iron-catalyzed double annulation of O-acyl oximes with fumaronitrile has been developed for the concise synthesis of polysubstituted 4-cyano-7-azaindoles. This method enables the construction of two fused heterocycles in a one-step reaction using readily available starting materials under redox-neutral conditions.