Cobalt-Catalyzed Sustainable Synthesis of Benzimidazoles by Redox-Economical Coupling of o-Nitroanilines and Alcohols.

This study reveals cobalt-catalyzed sustainable synthesis of benzimidazoles by redox-economical coupling of o-nitroanilines and alcohols. The major advantage of this report is the use of a commercially available cheap cobalt catalyst to produce a wide variety of 2-substituted benzimidazoles by hydrogen autotransfer without using any additional external redox reagent and costly ligand system. A thorough mechanistic insight of the reaction is proposed by performing a series of control experiments.