Recent Advances in the Synthesis of Benzimidazole Derivatives from the Oxidative Coupling of Primary Amines

Benzimidazole belongs to the top five most commonly used five-membered aromatic nitrogen heterocycles among U.S. FDA approved pharmaceuticals. Over the last few years, a large number of improved synthetic strategies have been developed to construct the benzimidazole molecular framework under environmentally benign conditions. This review focuses on the use of primary amines as readily available substrates for the synthesis of benzimidazole derivatives through different types of oxidative cross-coupling reactions. 1 Introduction 2 Catalyst-Free Oxidative Coupling of Primary Amines 3 Catalytic Oxidative Coupling of Primary Amines 3.1 Metal-Catalyzed Reactions 3.2 Metal-Free Catalyzed Reactions 3.3 Bioinspired Catalyzed Reactions 4 Conclusion