2,3-OXAZOLIDINONE PROTECTED ACETAMIDOGLYCOSIDES ARE EFFICIENT α- AND β- DIRECTING GLYCOSYL DONORS DUE TO CONTROLLABLE PRODUCT INTRAMOLECULAR ANOMERISATION (Abstracts)

摘要

One of the most common monosaccharide residues found in natural saccharides is N-acetyl glucosamine. Recently, 2,3-oxazolidinone protection of acetamido derivatives has been found to produce effective glycosyl donors circumventing the problems with competing oxazoline formation often encountered with N-acetyl glycosyl donors. Furthermore, thioethyl donors activated by NIS/AgOTf was shown to form glycosylation products with almost complete α- or β-stereoselectivity, rendering a simple access to both anomeric products. The stereochemical outcome of these high yielding glycosylation reactions was determined by more or less acidic coupling conditions, and an in situ anomerisation was suggested to explain these results .