Acceleration of the Baylis-Hillman reaction in the presence of ionic liquids

Abstract

The Baylis-Hillman reaction is accelerated in the presence of ionic liquids. Of various 1-butyl-3-methylimidazolium (bmim)-based ionic liquids tested, [bmim][PF6] has been found to result in the highest rate increase. In the company of Lewis acid and H-bond-donor additives, the reaction rates further improve, albeit only modestly. A preparatively useful Baylis-Hillman procedure prescribes the use of [bmim][PF6] with La(OTf)3 and 2,2′2″-nitrilotris [ethanol], in which the net effect of the ionic liquid is to bring about a more than twofold rate increase over the otherwise same reaction in MeCN.