Electrochemical intramolecular N(sp2)–H/N(sp3)–H coupling for the synthesis of 1H-indazoles

Abstract

The electrochemical synthesis of 1H-indazoles via an intramolecular N(sp²)–H/N(sp³)–H coupling reaction at room temperature is first described. The transition metal-free electrochemical cyclization features the use of commercially available NH₃ as the nitrogen source and a broad substrate scope, thus affording a wide range of substituted 1H-indazoles in moderate to good yields. Both the control experiments and mechanistic studies support the proposed reaction mechanism for this electrochemical cyclization.