Enantioselective Synthesis of Chiral Homoallyl Alcohols and Homoallylamines by Nucleophilic Addition of an Allylboron Reagent Modified by a Polymer-Supported Chiral Ligand

Abstract

Crosslinked polymer-supported chiral N-sulfonylamino alcohols 5–8 have been prepared by suspension polymerization of enantiopure N-sulfonylamino alcohol monomers 1–4 with styrene and divinylbenzene. Polymer-supported chiral allylboron reagents were prepared from the polymeric chiral ligands. Enantioselective additions of the polymer-supported allylboron reagents to aldehydes and N-(trimethylsilyl)imines have been successfully carried out in the heterogeneous system. The corresponding optically active homoallyl alcohols and homoallylamines were obtained in high yields with high enantioselectivities (up to 95% ee) which are almost the same as those obtained from homogeneous analogues. The polymer-supported chiral ligands used were recovered easily and can be reused without any loss of activity.