Electrooxidative Rhodium(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective C−H Annulation of Sulfoximines with Alkynes

• Published in: Angewandte Chemie 2024-04, Vol.136 (15), p.n/a
• Main Authors: Zhou, Gang, Zhou, Tao, Jiang, Ao‐Lian, Qian, Pu‐Fan, Li, Jun‐Yi, Jiang, Bo‐Yang, Chen, Zi‐Jia, Shi, Bing‐Feng
• Format: Article
• Language: English
• Subjects: Alkynes; Batch reactors; Carboxylic acids; Catalysis; Chemical reactions; chiral sulfoximines; C−H activation; Electrochemistry; Enantiomers; enantioselectivity; Organic chemistry; Rhodium; Room temperature; Transition metals
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202319871

The combination of achiral Cp*Rh(III) with chiral carboxylic acids (CCAs) represents an efficient catalytic system in transition metal‐catalyzed enantioselective C−H activation. However, this hybrid catalysis is limited to redox‐neutral C−H activation reactions and the adopt to oxidative enantioselective C−H activation remains elusive and pose a significant challenge. Herein, we describe the development of an electrochemical Cp*Rh(III)‐catalyzed enantioselective C−H annulation of sulfoximines with alkynes enabled by chiral carboxylic acid (CCA) in an operationally friendly undivided cell at room temperature. A broad range of enantioenriched 1,2‐benzothiazines are obtained in high yields with excellent enantioselectivities (up to 99 % yield and 98 : 2 er). The practicality of this method is demonstrated by scale‐up reaction in a batch reactor with external circulation. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle. An electrooxidative rhodium(III)/chiral carboxylic acid‐catalyzed enantioselective C−H annulation of sulfoximines with alkynes, is described. A broad range of enantioenriched 1,2‐benzothiazines are obtained in high yields with excellent enantioselectivities. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.