Silver-catalyzed TEMPO oxidative homocoupling of indoles for the synthesis of 3,3′-biindolin-2-ones

Abstract

An oxidative homo dimerization of free indole derivatives, by means of silver catalysis and TEMPO oxidant, was first successful demonstrated. This new methodology is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable substituted C3–C3′ bisindolin-2-ones in moderate to excellent yields.