Supported chiral catalysts: the role of the polymeric network

In the preparation of chiral-supported catalysts, the immobilization proces s can produce changes in the behavior of the resulting resin-supported spec ies. The polymeric matrix plays important roles that affect the activity, s electivity and stability of the final catalysts. Pseudodilution effects ver y often favor the activity of the supported species, and the presence of th e hydrophobic matrix increases the stability of the water-sensitive active sites. The steric interaction between the polymeric backbone and the groups in the chiral auxiliary can modify, even dramatically, the stereochemical outcome of the reaction. (C) 2001 Elsevier Science BN. All rights reserved.