On the Asymmetric Induction in Proline-Catalyzed Aldol Reactions: Reagent-Controlled Addition Reactions of 2,2-Dimethyl-1,3-dioxane-5-one to Acyclic Chiral alpha-Branched Aldehydes

Abstract

Reagent stereocontrol in the proline-catalyzed aldol reaction of 2,2-dimethyl-1,3-dioxane-5-one 1 with chiral aldehydes has been investigated. Synthetically useful levels of diastereoselectivity could be achieved in reactions with acyclic chiral alpha-oxy and alpha-amino aldehydes in both matched and mismatched cases. By using this reaction as a key step, two medicinally relevant azasugars, 1-deoxy-galactonojirimycin (9) and 2,5-dideoxy-2,5-imino-d-altritol (10), were efficiently synthesized.