Ferrier/Aza‐Wacker/Epoxidation/Glycosylation (FAWEG) Sequence to Access 1,2‐Trans 3‐Amino‐3‐deoxyglycosides

Abstract

3‐Amino‐3‐deoxyglycosides constitute an essential class of nitrogen‐containing sugars. Among them, many important 3‐amino‐3‐deoxyglycosides possess a 1,2‐trans relationship. In view of their numerous biological applications, the synthesis of 3‐amino‐3‐deoxyglycosyl donors giving rise to a 1,2‐trans glycosidic linkage is thus an important challenge. Even though glycals are highly polyvalent donors, the synthesis and reactivity of 3‐amino‐3‐deoxyglycals have been little studied. In this work, we describe a new sequence, involving a Ferrier rearrangement and subsequent aza‐Wacker cyclization that allows the rapid synthesis of orthogonally protected 3‐amino‐3‐deoxyglycals. Finally a 3‐amino‐3‐deoxygalactal derivative was submitted for the first time to an epoxidation/glycosylation with high yield and great diastereoselectivity, highlighting FAWEG (Ferrier/Aza‐Wacker/Epoxidation/Glycosylation) as a new approach to access 1,2‐trans 3‐amino‐3‐deoxyglycosides.