Anomerization of Methyl Glycosides by Acid-Catalysed Methanolysis: Trapping of Intermediates

Facile Approach to 2-Acetamido-2-deoxy-β-d-Glucopyranosides via a Furanosyl Oxazoline

“…The reaction of a furanose derivative to form a pyranoside requires opening of the anomeric acetal of the furanoside and formation of a new acetal linkage with the 5-hydroxyl group. Logically, this should lead to the formation of an open-chain GlcNAc intermediate.…”

Formation of the Glycosidic Linkage

“…Finally, a listing will be given of the less important or 'still rising' donors. Some examples are given below, together with a generally accepted mechanistic rationalization: 63,64 Microwave heating certainly accelerates the glycosidation process, but largescale reactors are not commonly available. 60 Hemiacetals A hemiacetal might appear to be the ultimate in terms of convenience when selecting a glycosyl donor, but it can be a 'wolf in sheep's clothing'; considerable synthesis is needed to access even a relatively simple molecule such as 2,3,4,6-tetra-O-benzyl-D-glucose.…”