Phosphine-Free Perfluoro-Tagged Palladium Nanoparticles Supported on Fluorous Silica Gel: Application to the Heck Reaction ² Roberta Bernini, ‡ Sandro Cacchi,* ,§ Giancarlo Fabrizi, § Giovanni Forte, | Sandra Niembro, ⊥ Francesco Petrucci, | Roser Pleixats, ⊥ Alessandro Prastaro, ‡ Rosa Maria Sebastia ´n, ⊥ Roger Soler, ⊥ Mar Tristany, ⊥ and Adelina Vallribera* ,⊥ Dipartimento A.B.A.C., UniVersita ` della Tuscia e Consorzio UniVersitario “La Chimica per l’Ambiente”, Via S. Camillo De Lellis, 01100 Viterbo, Italy, Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente AttiVe, UniVersita ` degli Studi “La Sapienza”, P.le A. Moro 5, 00185 Rome, Italy, Istituto Superiore di Sanita ` , Viale Regina Elena 299, 00161 Rome, Italy, and Department of Chemistry, UniVersitat Auto ` noma de Barcelona, Cerdanyola 08193, Spain sandro.cacchi@uniroma1.it; adelina.Vallribera@uab.es Received October 25, 2007 ABSTRACT The immobilization of phosphine-free perfluoro-tagged palladium nanoparticles Pd-1 on fluorous silica gel (FSG) and their utilization in the Heck reaction have been investigated. High yields of vinylic substitution products have been obtained. Recycling studies have shown that the solid-supported palladium catalyst can be readily recovered and reused several times without significant loss of activity. Reactions and recovery of the solid-supported palladium catalyst system can be carried out in the presence of air, without any particular precaution. Solid-supported palladium-catalyzed reactions have become a valuable tool for facilitating the separation, recovery, and reuse of expensive palladium catalysts and for reducing palladium contamination of the isolated products. Both of these problems are in fact of primary importance for the pharmaceutical industry which has to transfer laboratory- scale methods to large-scale cost-effective processes and limit the presence of heavy metal impurities in active substances. A large number of materials have been used to support palladium, including activated carbon, silica gel, polymers containing covalently bound ligands, metal oxides, porous aluminosilicates, clays and other inorganic materials, and microporous and mesoporous supports. 1 Palladium has also been microencapsulated in polymeric coating, 2 and aerogels 3 have been used to prepare heterogeneous palladium catalysts. Recently, some of us found that palladium nanoparticles can be stabilized by entrapment in perfluoro-tagged phos- phine-free compounds, 4 although heavily fluorinated com- pounds are not expected to be the best constituents of protecting shields for nanoparticles (perfluorinated chains are ² Dedicated to the memory of Prof. Marcial Moreno-Man ˜ as, a colleague and a friend. ‡ Universita ` della Tuscia e Consorzio Universitario “La Chimica per l’Ambiente”. § Universita ` degli Studi “La Sapienza”. | Istituto Superiore di Sanita `. ⊥ Universitat Auto `noma de Barcelona. (1) For an excellent recent review on the use of heterogeneous palladium catalysts in C-C bond-forming reactions, see: Yin, L.; Liebscher, J. Chem. ReV. 2007, 107, 133. ORGANIC LETTERS 2008 Vol. 10, No. 4 561-564 10.1021/ol7024845 CCC: $40.75 © 2008 American Chemical Society Published on Web 01/19/2008