Domino Ring-Opening Cyclization of Activated Aziridines with Indoles: Synthesis of Chiral Hexahydropyrroloindoles

A highly enantioselective synthetic route to hexahydropyrrolo­[2,3-b]­indoles via Lewis acid-catalyzed SN2-type ring opening of activated aziridines with indoles having substitutions at 3- and other positions followed by cyclization in a domino fashion has been developed. Hexahydropyrrolo­[2,3-b]­indoles have been detosylated in the same pot to afford the corresponding products with free NH group in excellent yields (up to 95%) and enantioselectivity (up to >99%).