Enantioselective synthesis of hydroxy-substituted DBN-type amidines as potential chiral catalysts

The synthesis and X-ray crystal structures of three enantiopure hydroxy-sub stituted amidines of the DBN-type are described. The key starting material, a 5-(phenylsulfonyl)pyrrolidin-2-one, was obtained by an oxazaborolidine-c atalysed reductive desymmetrization of a meso-imide and was functionalized through N-acyliminium ion chemistry. The hydroxy groups were introduced by ozonolysis or reduction. Preliminary results on the use of the hydroxyamidi nes as chiral, bifunctional catalysts in selected Michael reactions are des cribed.