Environmentally friendly and regioselective C3-alkylation of indoles with alcohols through a hydrogen autotransfer strategy

The direct alkylation of indoles using KOH and alcohols, as initial source of the electrophile, under solvent-free conditions is a safe and environmentally benign strategy for selective modification of these structures at the C3-position, without using hazardous and difficult to handle bromide or iodide derivatives or toxic and expensive transition metal catalysts. The protocol shows a broad scope, including halogenated indoles and secondary alcohols.

This work was supported by the current Spanish Ministerio de Economía y Competitividad (Consolider Ingenio 2010 CSD2007-00006, CTQ2011-24151) and the Generalitat Valenciana (G.V.; PROMETEO 2009/03, FEDER). R.C. thanks to G.V. for a fellowship through the PROMETEO program.