TEMPO-catalyzed oxidative homocoupling route to 3,2′-biindolin-2-ones via an indolin-3-one intermediate

Abstract

A combinative C2-selective arylation, and C3-selective carbonylation of free indole derivatives, by means of TEMPO catalysis and a silver oxidant under non-directing group conditions, was 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 3,2′-biindolin-2-ones in moderate to excellent yields.