Gold/Copper-Co-catalyzed Tandem Reactions of 2-Alkynylanilines: A Synthetic Strategy for the C2-Quaternary Indolin-3-ones

A new strategy for direct and highly efficient synthesis of 2,3'-bisindolin-3-ones has been developed via a gold/copper-co-catalyzed tandem reactions of 2-alkynylanilines using TBHP as the terminal oxidant and oxygen-atom source. The single-step process involves a novel tandem intermolecular nucleophilic addition, intramolecular cyclization/oxidative cross-dehydrogenative coupling where up to four new bonds and two indole rings were created simultaneously in one-pot manner. The reaction features a broad substrate scope, good functional group tolerance, and high atom-economy.