The pentasaccharide repeating unit rich in 2-acetamido sugars corresponding to the
O-antigenic polysaccharide from enteropathogenic Escherichia coli (E. coli) has been synthesized as the p-methoxyphenyl glycoside in excellent yield using a sequential glycosylation strategy.
Regioselective glycosylation, use of a single monosaccharide intermediate in multiple
glycosylations, and use of thioglycosides as glycosyl donors in the presence of a
combination of N-iodosuccinimide (NIS) and perchloric acid supported over silica (HClO4–SiO2) are key components of the synthetic strategy. All glycosylation reactions were high-yielding
with excellent stereochemical outcome.
Key words
carbohydrates - glycosylation - glycosides - oligosaccharides - synthesis -
E. coli
