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.
The facile synthesis of 2-bromoindoles via Cs<sub>2</sub>CO<sub>3</sub>-promoted intramolecular cyclization of 2-(gem-dibromovinyl)anilines under transition-metal-free conditions
作者:Pinhua Li、Yong Ji、Wei Chen、Xiuli Zhang、Lei Wang
DOI:10.1039/c2ra22172a
日期:——
2-Bromoindoles were readily prepared through a facile Cs2CO3-promoted intramolecular cyclization of 2-(gem-bromovinyl)-N-methylsulfonylanilines in excellent yields under transition-metal-free conditions. This methodology could be extended to the synthesis of corresponding 2-chloroindoles. The reaction mechanism suggested that cyclization occurs through a key intermediate, phenylethynyl bromide, followed by cyclization in one-pot.