2,2,6,6‐Tetramethylpiperidin‐1‐oxyl‐Regulated Divergent 1,5‐ and 1,2‐Hydrogen Atom Transfer for Site‐Selective C(sp ³ )─H Aminations in Continuous Flow

Developing site‐selective, atom‐economic methods to construct multinitrogenous frameworks directly from unactivated hydrocarbons remains a key challenge in green chemistry. Herein, we report a transition‐metal‐free, visible‐light‐driven divergent amination strategy for the programable synthesis of δ ‐diamines and α ‐gem‐diamines from a unified class of N─O bifunctional precursors. By integrating photoredox energy transfer with continuous‐flow engineering, this protocol bypasses light‐penetration bottlenecks, achieving rapid conversions within residence times of less than 40 min. Mechanistically, TEMPO (2,2,6,6‐tetramethylpiperidin‐1‐oxyl) operates counterintuitively as a chemoselective switch rather than a radical scavenger; its presence or absence precisely dictates the bifurcation between an inherently favored 1,5‐HAT (hydrogen atom transfer) pathway and a formal 1,2‐HAT cascade. The method demonstrates robust functional‐group tolerance across diverse C(sp ³ )─H bonds, including unactivated secondary/tertiary aliphatic sites and adamantane skeletons. Its scalability and synthetic utility are highlighted by a 1.0 g synthesis without parameter reoptimization and late‐stage conversions into key γ ‐amino amides and diamine derivatives. Free of hazardous initiators or toxic metals, this platform offers a sustainable blueprint for scalable radical transformations.