Cobalt‐Catalyzed C─N Bond Formation via Metal‐Hydride Hydrogen Atom Transfer (MHAT)

ABSTRACT Nitrogen‐containing molecules are ubiquitous in pharmaceuticals, agrochemicals, and functional materials, making the development of efficient C─N bond‐forming reactions a central goal in synthesis. Cobalt‐catalyzed metal–hydride hydrogen atom transfer (Co─H/MHAT) has emerged as a powerful platform for alkene hydroamination by enabling the controlled generation of carbon‐centered radicals under mild and near‐neutral conditions. This review summarizes the development of Co–MHAT‐enabled C─N bond formation from its origins to recent advances, tracing all transformations to a common Co─H‐initiated radical/organocobalt branch point. Across both reductive Co/photoredox and oxidative Co–MHAT manifolds, a common Co─H‐initiated step generates a shared radical/organocobalt intermediate that can be directed into distinct pathways, including radical–radical coupling (RRC), radical–polar crossover (RPC), and radical ligand transfer (RLT). These complementary reactivity modes enable amination at sterically hindered and electronically unbiased sites. Collectively, Co–MHAT catalysis offers a versatile and conceptually distinct strategy for selective C─N bond construction.