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.
在不含过渡金属的条件下,通过 Cs2CO3 促进的 2-(偕溴乙烯基)-N-甲基磺酰基苯胺的分子内环化,可以轻松制备 2-溴吲哚,收率优异。该方法可以扩展到相应的 2-氯吲哚的合成。反应机理表明,环化是通过关键中间体苯乙炔基溴发生的,然后是一锅环化。