Enantio‐ and Regioselective Electrooxidative Cobalt‐Catalyzed C−H/N−H Annulation with Alkenes

Abstract

In recent years, the merging of electrosynthesis with 3d metal catalyzed C−H activation has emerged as a sustainable and powerful technique in organic synthesis. Despite the impressive advantages, the development of an enantioselective version remains elusive and poses a daunting challenge. Herein, we report the first electrooxidative cobalt‐catalyzed enantio‐ and regioselective C−H/N−H annulation with olefins using an undivided cell at room temperature (up to 99 % ee). ^t Bu‐Salox, a rationally designed Salox ligand bearing a bulky tert‐butyl group at the ortho‐position of phenol, was found to be crucial for this asymmetric annulation reaction. A strong cooperative effect between ^t Bu‐Salox and 3,4,5‐trichloropyridine enabled the highly enantio‐ and regioselective C−H annulation with the more challenging α‐olefins without secondary bond interactions (up to 96 % ee and 97 : 3 rr). Cyclovoltametric studies, and the preparation, characterization, and transformation of cobaltacycle intermediates shed light on the mechanism of this reaction.