Recent developments in asymmetric synthesis of cyclohepta[b]indole derivatives

Abstract

Cyclohepta[b]indole derivatives constitute a prominent class of indole-annulated medium-sized ring systems that occur in diverse bioactive natural products and pharmaceutically relevant scaffolds. Their enantioselective construction, however, remains intrinsically challenging owing to conformational flexibility, transannular interactions, and unfavorable thermodynamic/entropic features associated with seven-membered ring formation. This review summarizes progress in emerging asymmetric methodologies that deliver chiral cyclohepta[b]indole frameworks, by highlighting advances in catalyst design, reaction efficiency, and stereocontrol, alongside mechanistic insights that rationalize selectivity trends and guide future development.