Manganese Catalyzed Oxidative Coupling of Aromatic Diamines and Alcohols with Aminoxyl Radicals in the Synthesis of Benzimidazoles

Abstract We herein report a solvent‐free, oxidative coupling reaction of alcohols with aromatic diamines in air. 9‐Azabicyclo[3.3.1]nonan‐N‐oxyl (ABNO) in combination with a manganese(II) catalyst, serves to effectively promote the reaction, leading to the selective synthesis of 2‐substituted benzimidazoles and 1,2‐disubstituted benzimidazoles.