Asymmetric C–H Dehydrogenative Alkenylation via a Photo-induced Chiral α‑Imino Radical Intermediate
Zongbin Jia, Liang Cheng, Long Zhang, Sanzhong Luo
Abstract
Abstract 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.