Asymmetric Counteranion‐Directed Electrocatalysis for Enantioselective Control of Radical Cation

Abstract

The control of enantioselectivity in radical cation reactions presents long‐standing challenges, despite a few successful examples. We introduce a novel strategy of asymmetric counteranion‐directed electrocatalysis to address enantioselectivity in radical cation chemistry. This concept has been successfully demonstrated in two reactions: an asymmetric dehydrogenative indole‐phenol [3+2] coupling and an atroposelective C−H/N−H dehydrogenative coupling. These reactions have enabled the synthesis of benzofuroindolines and C−N axially chiral indoles with high yields and excellent enantiomeric excesses. Detailed mechanistic studies confirmed a radical‐radical coupling mechanism. Moreover, density functional theory (DFT) calculations supported the indole radical cation as the pivotal intermediate, rather than a neutral indolyl radical, shedding new light on the underlying processes driving these reactions.