Cooperative Organosulfur/Photoredox Catalysis Enables Radical-Polar Crossover C(sp3)–N Coupling via Inner-Sphere Electron Shuttling

Radical-polar crossover (RPC) is a valuable mechanistic tool for revitalizing traditional radical and polar chemistries by integrating them. However, transitioning from radical to polar pathways across multiple redox events requires precise redox potential matching between the reaction components (catalysts and substrates), which inherently limits the scope of these transformations. Here, we present a cooperative catalytic platform that diverts the key RPC mechanism from outer-sphere to inner-sphere manifolds, enabling C(sp3)-N coupling of redox active esters with otherwise oxidizable (hetero)arylamines. The key to success is the identification of organosulfur catalyst capable of selectively shuttling electrons between the photocatalyst and the incipient radical in preference to competing arylamine oxidation. Experimental and computational studies reveal that the tailored organosulfur catalyst plays a crucial role in steering the post-radical generation steps to guide the desired reaction trajectory for C(sp3)-N bond formation. This method displays good functional group compatibility and chemoselectivity, providing an efficient route to functionally rich secondary and tertiary arylamines. The virtue of this method was further demonstrated by late-stage applications for synthesizing medically relevant nitrogen-containing compounds.