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Synthesis of α-Quaternary β-Lactams via Copper-Catalyzed Enantioconvergent Radical C(sp3)−C(sp2) Cross-Coupling with Organoboronate Esters |
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| Authors: | Dr Fu-Li Wang Dr Lin Liu Dr Chang-Jiang Yang Cheng Luan Dr Jing Yang Dr Ji-Jun Chen Dr Qiang-Shuai Gu Dr Zhong-Liang Li Prof Dr Xin-Yuan Liu |
| Institution: | 1. School of Science and Institute of Scientific Research, Great Bay University, Dongguan, 523000 China
Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055 China These authors contributed equally to this work.;2. School of Science and Institute of Scientific Research, Great Bay University, Dongguan, 523000 China Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055 China;3. Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055 China Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 China;4. College of Health Science and Environmental Engineering, Shenzhen Technology University, Shenzhen, 518118 China;5. Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055 China;6. Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 China |
| Abstract: | The copper-catalyzed enantioconvergent radical C(sp3)−C(sp2) cross-coupling of tertiary α-bromo-β-lactams with organoboronate esters could provide the synthetically valuable α-quaternary β-lactams. The challenge arises mainly from the construction of sterically congested quaternary stereocenters between the tertiary alkyl radicals and chiral copper(II) species. Herein, we describe our success in achieving such transformations through the utilization of a copper/hemilabile N,N,N-ligand catalyst to forge the sterically congested chiral C(sp3)−C(sp2) bond via a single-electron reduction/transmetalation/bond formation catalytic cycle. The synthetic potential of this approach is shown in the straightforward conversion of the corresponding products into many valuable building blocks. We hope that the developed catalytic cycle would open up new vistas for more enantioconvergent cross-coupling reactions. |
| Keywords: | Asymmetric Catalysis Copper Cross-Coupling Radical Chemistry β-Lactam |