Organo/Metal-Catalyzed C-H Amination of Nitrogenous Heterocycles: Recent Advances

The functionalization of C-H bonds has developed as a vital strategy in modern organic synthesis to obtain structurally diverse and biologically relevant molecules. Transition-metalcatalyzed direct C-H bond amination (CH-BA) represents a promising approach for the synthesis of nitrogen-containing heterocyclic compounds, which are prevalent in natural products and pharmaceuticals. Metals such as ruthenium, palladium, iridium, rhodium, iron, manganese, copper, nickel, and cobalt have gained attention due to their relative abundance, lower toxicity, and biocompatibility. On the other hand, the rational design of catalysts remains challenging, primarily because common agostic hydrogen intermediates are absent. Recent developments in metal-catalyzed CH-BA have significantly expanded the scope of synthetic methodologies. This study highlights key recent developments in this area, emphasizing the mechanistic diversity and catalytic efficiency achieved through modified metal-ligand frameworks. The exploration bridges various catalytic systems offering potential reactivity profiles and synthetic applications.