A Synthetic Route to Chiral Tetrahydropyrroloindoles via Ring Opening of Activated Aziridines with 2-Bromoindoles Followed by Copper-Catalyzed C-N Cyclization.

Abstract

A new synthetic route to nonracemic tetrahydropyrrolo[2,3-b]indoles has been developed via SN2-type ring opening of enantiopure N-activated aziridines with 2-bromoindoles followed by copper-catalyzed C-N cyclization. A series of N-activated aziridines and 2-bromoindole derivatives with different substitution patterns were studied to afford the corresponding tetrahydropyrrolo[2,3-b]indoles in good yields and excellent ee (up to 99%). Highly substituted tetrahydropyrrolo[2,3-b]indole was synthesized as a single stereoisomer (de, ee >99%) from enantiopure trans-disubstituted aziridine.