Cyclization of Azobenzenes Via Electrochemical Oxidation Induced Benzylic Radical Generation

Abstract

An electrochemical oxidation-induced cyclization of <i>ortho</i>-alkyl-substituted azobenzenes has been developed. The direct electrochemical benzylic C-H functionalization with respect to azobenzenes could proceed in the absence of any catalyst or external chemical oxidant to afford a number of 2<i>H</i>-indazole derivatives in moderate to good yields. This protocol enables the reuse of the byproduct to the same 2<i>H</i>-indazoles, thus significantly reducing pollution discharge in synthetic chemistry.