Facile Construction of Pyrrolo[1,2-a]indolenine Scaffold via Dia­stereoselective [3+2] Annulation of Donor–Acceptor Cyclopropane with Indolenine

Abstract

A novel synthetic protocol for the assembly of pyrrolo[1,2-a]indolenine has been developed through a highly diastereoselective [3+2] annulation of 1,1-cyclopropanediesters with indolenines in the presence of catalytic Yb(OTf)3. This new strategy allows a facile construction of the multicyclic system with the flexible variation on the substituents in high yields (up to 86%) with excellent diastereoselectivities (>20:1 dr) in most cases.