Zhao Hongping, Hu Yuanyuan, Zheng Songlin, Yuan Weiming
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, PR China.
Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518000, PR China.
Org Lett. 2023 Sep 15;25(36):6699-6704. doi: 10.1021/acs.orglett.3c02507. Epub 2023 Sep 7.
Facile access to sterically hindered α-tertiary primary amines via photocatalytic radical coupling of native C(sp)-H substrates with -unsubstituted ketimines is reported. LiBr was used as a hydrogen atom transfer reagent to cleave C(sp)-H bonds to get alkyl radicals. The in situ-generated HBr can then serve as a Bronsted acid to activate -unsubstituted ketimines readily for single-electron reduction to deliver α-amino radicals. As a consequence, radical-radical coupling affords primary amines with a congested α-tertiary substituent. This reaction is highlighted by simple and mild conditions, 100% atom-economy, and broad hydrocarbon substrate scope for benzyl ethers, cyclic ethers, benzyl alcohols, alkylarenes, and carbocycles.
报道了通过天然C(sp)-H底物与未取代酮亚胺的光催化自由基偶联，简便地获得空间位阻α-叔伯胺。LiBr用作氢原子转移试剂以裂解C(sp)-H键得到烷基自由基。原位生成的HBr随后可作为布朗斯特酸，容易地活化未取代酮亚胺以进行单电子还原，从而产生α-氨基自由基。因此，自由基-自由基偶联得到具有拥挤α-叔取代基的伯胺。该反应的特点是条件简单温和、原子经济性100%以及苄基醚、环醚、苄醇、烷基芳烃和碳环的烃底物范围广泛。
