Asymmetric C–H Dehydrogenative Alkenylation via a Photo-induced Chiral α‑Imino Radical Intermediate

The direct alkenylation with simple alkenes stands out as the most ideal yet challenging strategy for obtaining high-valued desaturated alkanes. Here we present a direct asymmetric dehydrogenative α -C(sp 3 )-H alkenylation of carbonyls based on synergistic photoredox-cobalt-chiral primary amine catalysis under visible light. The ternary catalytic system enables the direct coupling of β -keto-carbonyls and alkenes through a cooperative radical addition-dehydrogenation process involving a chiral α -imino radical and Co(II)-metalloradical intermediate. A catalytic H-transfer process involving nitrobenzene is engaged to quench in situ generated cobalt hydride species, ensuring a chemoselective alkenylation in good yields and high enantioselectivities. The direct alkenylation with simple alkenes stands out as the most ideal yet challenging strategy for obtaining high-valued desaturated alkanes. Herein, the authors present a direct asymmetric dehydrogenative α -C(sp3)-H alkenylation of carbonyls based on synergistic photoredox-cobalt-chiral primary amine catalysis under visible light.