Redox‐Neutral C(sp3)─H Alkenylation via Photocatalyzed Tandem Hydrogen Atom Transfer and Downstream Oxidative Radical Polar Crossover

Herein, we present a photocatalytic route that exploits a redox-neutral tandem hydrogen atom transfer (HAT) and oxidative radical polar crossover (RPC) manifold. This method enables the efficient synthesis of valuable allylic amides and ethers through the valorization of three classes of ubiquitous feedstock chemicals: carboxylic acids as precursors to hydrogen atom abstractors, amides or ethers as C(sp3)─H donors, and olefins as radical acceptors. The protocol operates under mild conditions, exhibits broad functional group tolerance, and is readily scalable. The redox-neutral nature of this transformation mechanistically distinguishes it from traditional net-oxidative approaches associated with exogenous stoichiometric oxidants. Crucially, it allows HAT substrates bearing “hydridic” C─H bonds (e.g., α- to heteroatom: X─CHR1R2) to be engaged in Giese-type addition reactions and subsequent oxidative RPC/nucleophilic trapping, where traditional net-oxidative approaches inevitably result in Shono-type further oxidation of the HAT-derived radical (e.g., α- to heteroatom: X+═CR1R2) and nucleophilic interception prior to intermolecular radical addition.