INTRAMOLECULAR CYCLOADDITION REACTIONS OF OMEGA-UNSATURATED CHIRAL NITRONES

The intramolecular 1,3-dipolar cycloaddition of omega-unsaturated chir al nitrones is described. Starting materials for this reaction are O-p rotected chiral cyanohydrins, prepared by an R-oxynitrilase catalyzed asymmetric addition of hydrogen cyanide to omega-unsaturated aldehydes . Intra-molecular cycloaddition, followed by reductive opening of the isoxazolidine ring, produced five- and seven-membered ring compounds w ith chiral hydroxy and amine functionalities of high enantiomeric puri ty in excellent yield.