Sc(OTf)3-Catalyzed Oligomerization of Indole: One-Pot Synthesis of 2-[2,2-Bis(indol-3-yl)ethyl]anilines and 3-(Indolin-2-yl)indoles

Abstract

Oligomerization of substituted indoles and N-methylindoles was investigated in the presence of catalytic amounts of scandium triflate in dichloromethane. Two types of indole oligomer, 2-[2,2-bis(indol-3-yl)ethyl]anilines and 3-(indolin-2-yl)indoles were obtained based on the substituent on indole ring. This study constitutes the first example of Sc(OTf)3-catalyzed oligomerization of indoles and gave good yield of 2-[2,2-bis(indol-3-yl)ethyl]anilines and 3-(indolin-2-yl)indoles.