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

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 were obtained in high yields with excellent enantioselectivities (up to 99% yield and 98:2 er). The practicality of this method was demonstrated by scale‐up reaction in a batch reactor with external circulation. A crucial chiral Cp*Rh(III) intermediate was isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.