Bismuth(III) Triflate Catalyzed Condensation of Isatin with Indoles and Pyrroles­: A Facile Synthesis of 3,3-Diindolyl- and 3,3-Dipyrrolyl Oxindoles

Abstract

Indoles and pyrroles undergo a rapid condensation with isatin in the presence of 2 mol% of Bi(OTf) 3 , under mild reaction conditions, to afford the corresponding 3,3-di(3-indolyl)- and 3,3-di(2-pyrroryl)oxindoles in excellent yields and high regioselectivity. This method is ideal for the direct introduction of indoles and pyrroles onto an isatin moiety at the 3-position.