Journal of Molecular Catalysis A-Chemical, Vol.276, No.1-2, 137-142, 2007
The synthesis of supported proline-derived ligands and their application in asymmetric diethylzinc addition to aldehydes
Attachment of the proline-derived ligand 5 to two types of polymers, i.e. aminomethylated polystyrene resin and respectively MeO-PEG, was achieved via a succinyl linkage from the 4-hydroxy group. Both of the supported ligands (7 and 8) were proved to be highly active with good enantioselectivity (up to 90% ee) for the catalyzed asymmetric diethylzinc addition to aldehydes. The insoluble polymer-supported catalyst could be easily recovered and was reusable for several consecutive catalytic runs without significant loss in enantioselectivity. (c) 2007 Elsevier B.V. All rights reserved.