Ring-closure metathesis in supercritical carbon dioxide as sole solvent with use of covalently immobilized ruthenium catalysts

We describe RCM reactions in the presence of a Hoveydatype catalyst covalently immobilized on different support materials. The performance of the catalyst was highly dependent on the nature of the support, and in some cases high levels of conversion were obtained, allowing for repetitive cycles. In addition, remarkably low levels of leaching of ruthenium. into the product (20 ppm) were observed. This environmentally benign process has potential for continuous applications. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)