Aldolreactions of a chelated glycine ester enolate with a chiral aldehyde gives rise to the corresponding polyhydroxylated aminoacid with excellent induced diastereoselectivity. These oxygenated aminoacids can be converted into polyhydroxylated pipecolinic acids and azasugars by cyclization using the Mitsunobu reaction. An interesting epimerization was observed during the cyclization. The potential