Ru-catalyzed oxidation and C–C bond formation of indoles for the synthesis of 2-indolyl indolin-3-ones under mild reaction conditions

Abstract

Herein, we described a ruthenium catalyzed oxidation and C–C bond formation reaction of 2-alkyl or 2-aryl substituted indoles using tert-butyl hydroperoxide (TBHP) as oxidant. Coupled with cascade transformation, it provided a mild catalytic oxidation system for the synthesis of 2-indolylindolin-3-ones. The reaction could readily occur using RuCl3·3H2O as catalyst, and the target product was obtained with medium to high yield.