Rh(III)-Catalyzed Asymmetric Synthesis of Axially Chiral Biindolyls by Merging C–H Activation and Nucleophilic Cyclization

Enantiomeric access to pentatomic biaryls is challenging due to their relatively low rotational barrier. Reported herein is the mild and highly enantioselective synthesis of 2,3'-biindolyls via underexplored integration of C-H activation and alkyne cyclization using a unified chiral Rh(III) catalyst. The reaction proceeded via initial C-H activation followed by alkyne cyclization. A chiral rhodacyclic intermediate has been isolated from stoichiometric C-H activation, which offers direct mechanistic insight.