Synthesis of polymeric chiral L-prolinol derivatives and its applications on the asymmetric Michael addition

N-acylation Of L-prolinol (2) with enoyl chloride provided L-cinnamoylprolinol (3a) and L-crotonylprolinol (3b), respectively. The attachment of (3a) or (3b) to Merrifield resin and the utilization of such a system for asymmetric Michael additions of Grignard reagents to alpha, beta -unsaturated carbonyl compounds were studied. The stereoselectivities have been increased compared with those observed for the same reactions in solution. On the other hand, it has been proved by the FT-IR difference spectrum of the Merrifield resin and polymer-supported chiral auxiliary that L-prolinol derivatives have been coupled to the resin. (C) 2001 Elsevier Science B.V. All rights reserved.