Recent advances in C(sp<sup>3</sup>)–H functionalization via nitrogen-centered radical-mediated 1,2-hydrogen atom transfer

<p indent="0mm">The selective functionalization of C(sp³)–H bonds represents one of the core challenges in modern organic synthesis. In recent years, the strategy of nitrogen-centered radical-mediated 1,2-hydrogen atom transfer (1,2-HAT) has garnered significant attention as a powerful and efficient solution. This approach involves the selective ion of a proximal hydrogen atom by an <italic>in situ</italic> generated nitrogen-centered radical, enabling the transformation of inert C(sp³)–H bonds into key carbon-centered radicals. These intermediates subsequently undergo coupling with various reaction partners, achieving nitrogen adjacent position and site-selective functionalization. This review systematically summarizes recent advances in this field, with a focus on the design and development of nitrogen-radical precursors such as <italic>N</italic>-aroyloxyamides, <italic>N</italic>-aryloxyamides, <italic>N</italic>-alkoxyamides, and hydroxamic esters. The underlying mechanisms of the 1,2-HAT process under photoredox catalysis, transition metal catalysis, or metal-free conditions are thoroughly discussed. The successful application of this strategy in constructing C–C and C–X bonds is elaborated, highlighting its notable advantages, including mild reaction conditions, excellent functional group tolerance, and applicability in late-stage functionalization of complex molecules. Finally, current challenges—such as precise control of selectivity and the development of asymmetric catalysis—are addressed, and future research directions are outlined. It is envisioned that the nitrogen-radical-mediated 1,2-HAT strategy will continue to provide sustained impetus for the efficient synthesis of innovative pharmaceuticals and functional molecules.