Electrocatalytic Enantioselective Tandem C–H Indolization toward Biindolyl Atropisomers: Reaction Development and Mechanistic Insight

The electrochemical methods for asymmetric indolization are still elusive and pose a significant challenge. Taking advantage of 2-alkynylanilines as electrochemically compatible indolyl equivalents, we herein represent a mild and highly enantioselective electrocatalytic process for tandem C–H indolization to form 2,3′-biindolyl atropisomers along with hydrogen evolution reaction. Integrated experimental and computational mechanistic studies revealed that a sequential C–H metalation/nucleophilic cyclization/reductive elimination/anodic oxidation sequence involving a RhIII–RhI–RhIII catalytic cycle accounts for the established transformation.