Manganese‐Catalyzed CH Functionalization Reactions of Arenes

Abstract Manganese‐catalyzed CH functionalization reactions have evolved as an efficient strategy to construct new CC, CN, CO, and CS bonds and provide an alternative pathway to classical cross‐coupling reactions. Unlike the classical cross‐coupling catalysts like palladium (Pd) and iridium (Ir) or toxic 4d and 5d transition metal catalysts like rhenium (Re) and rhodium (Rh) that have been used for CH functionalization, 3d transition metals will be an excellent choice. Manganese is one of the most nontoxic and earth‐abundant metals available at a very low cost. Subsequently, usage of manganese catalysts has vastly increased mainly because of their application in the synthesis of active pharmaceutical ingredients. Herein, we will discuss various arene and olefin CH functionalization reactions catalyzed by manganese and assisted by diverse directing groups. The article will culminate in a discussion of the applications of manganese‐catalyzed CH functionalization via radical pathways for the generation of interesting heterocycles.