Visible-Light-Induced Manganese-Catalyzed Reactions: Present Approach and Future Prospects

Visible-light-induced reactions have allowed researchers to attain unorthodox bond formation and elusive chemical processes under mild and inherently safe reaction conditions. However, these methods have relied heavily on Ru- and Ir-based complexes or metal-free chromophores. While the heavy transition metal complexes are limited by their high cost, toxicity, and adverse environmental effects. Metal-free photo-redox catalysts are restricted due to their poorer photo-stability. In order to overcome these shortcomings, extensive research aimed towards utilizing 3d-transition metals has come to the forefront. Manganese, in this regard, holds great promise as a versatile and economically sustainable 3d-transition metal catalyst. Hence, it is not surprising that recent years have witnessed several advances in visible-light-mediated manganese catalysis in areas of organic, polymer, and materials chemistry. Manganese-based heterogeneous systems have also been utilized to effect dimerization and oxygenation reactions showcasing the versatility of manganese. Moreover, manganese has enabled late-stage functionalization of valuable medicinal compounds and natural products, which are all important from the viewpoint of medicinal and pharmaceutical chemistry. In the present review, comprehensive discussions on the advances, significance, approaches, and mechanistic aspects have been added for each photochemical reaction process. Further, the reaction scope, limitations, and future prospects of visible-light-induced manganese catalysis have also been reviewed.

Automated summary

Manganese as a novel visible-light-induced catalyst shows great promise in terms of economic sustainability and applicability, leading to significant advancements in organic, polymer, and materials chemistry fields in recent years. Through manganese-catalyzed reactions, late-stage functionalization of valuable compounds and natural products can be realized, which is important for the development of medicinal and pharmaceutical chemistry.