Imidazolium-based polymer supported gadolinium triflate as a heterogeneous recyclable Lewis acid catalyst for Michael additions

A heterogeneous Lewis acid catalytic system has been developed by incorporating gadolinium triflate on to poly[styrene-co-(1-((4-vinylphenyl)methyl)-3-methylimidazolium) tetrafluoroborate] (1-Gd(OTf)(3)), and the catalytic activity of this system has been examined for Michael additions of amines and thiols to alpha, beta-unsaturated esters and acrylonitrile. The reactions proceed in moderate to excellent yields in the presence of catalytic system 1-Gd(OTf)(3). The catalytic system could be efficiently recycled and reused. (C) 2008 Elsevier Ltd. All rights reserved.