Copper-catalysed intramolecular O-arylation of aryl chlorides and bromides: a straightforward approach to benzo[d]oxazoles in water

A general, efficient and more sustainable protocol for the copper-catalysed intramolecular O-arylation of o′-haloanilides leading to the benzo[d]oxazole core is reported. Remarkably, the optimised conditions allowed for the use of inexpensive and easily available aryl chlorides as arylating agents. Moreover, all reactions were carried out employing exclusively water as the solvent, rendering the methodology presented herein highly valuable from both environmental and economic points of view.