The facile synthesis of 2-bromoindoles via Cs2CO3-promoted intramolecular cyclization of 2-(gem-dibromovinyl)anilines under transition-metal-free conditions
A mild and efficient synthesis of 2-bromoindoles by ligand-free CuI-catalyzed intramolecular cross-coupling of gem-dibromoolefins was developed. Reactions were carried out in toluene at room temperature and the corresponding 2-bromoindoles were obtained in excellent yields. (C) 2010 Elsevier Ltd. All rights reserved.