Immobilization of Bis(oxazolinyl)pyridines
A. Cornejo, J. M. Fraíle, J. I. García, M. J. Gil, S. V. Luis, V. Martínez-Merino*, J. A. Mayoral*
Universidad Pública de Navarra, Universidad de Zaragoza-CSIC and Universidad Jaume I, Spain
21 September 2005 (online)
Bis(oxazolinyl)pyridine ligands (pybox) having various tether groups were anchored on polystyrene resin via copolymerization or grafting. The utility of the polymeric pybox ligands were examined for Ru-catalyzed asymmetric cyclopropanation of styrene. Ligand 2 showed good stability in four subsequent reuses under optimized conditions (52-70% yields, 90:10 trans/cis selectivity and 85-91% ee for trans-cyclopropanes).