Photocatalytic C(sp3)-H gem-Difluoroallylation and Alkylation with Alkenes via a Base-Assisted Formal 1, 2-Hydrogen Atom Transfer of Amidyl Radicals
Meifang Tang , Bingbing Feng , Yanyang Bao , Zhongtian Xu , Chao Huang , Hanliang Zheng , Gangguo Zhu , Yanan Wang , Zheliang Yuan
Chinese Journal of Chemistry ›› 2024, Vol. 42 ›› Issue (18) : 2203 -2210.
Photocatalytic C(sp3)-H gem-Difluoroallylation and Alkylation with Alkenes via a Base-Assisted Formal 1, 2-Hydrogen Atom Transfer of Amidyl Radicals
Compared to well-established 1, 5-HAT of N-centered radicals, the synthetic applications of 1, 2-HAT process were scarce due to the high barrier and constrained three-membered transition state. Here, we have developed a novel C(sp 3)-H gem-difluoroallylation via a base assisted formal 1, 2-HAT of amidyl radicals with the reductive quenching cycle of photocatalyst. This transformation enables the efficient formation of α-aminoalkyl radicals via 1, 2-HAT and showcases good functional group tolerance. Our preliminary mechanistic experiments, along with Density Functional Theory (DFT) calculations demonstrate the feasibility of 1, 2-HAT of amidyl radicals, especially when assisted by a base. Furthermore, our method also succeeds in the Giese addition of electron-deficient alkenes as well as styrene.
1,2-Hydrogen atom transfer / Amidyl radicals / gem-Difluoroallylation / Alkenes / Photocatalysis / Defluoroalkylation
2024 SIOC, CAS, Shanghai, & WILEY-VCH GmbH
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