Synthetic approach to 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) α-disaccharides via a ketene dithioacetal

First and stereoselective synthesis of an α-(2→5)-linked disaccharide of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)

Resistance of bacterial pathogens toward antibiotics has revived interest in lipopolysaccharide (LPS) motifs as potential therapeutic targets. The LPS of several pathogenic Acinetobacter strains comprises a 4,5-branched Kdo trisaccharide containing an uncommon (2→5)-linkage. In this contribution the first stereoselective glycosylation method for obtaining an α-Kdo-(2→5)-α-Kdo disaccharide in good yield is highlighted. The synthetic approach used for accessing this linkage type will allow for future studies of the immunoreactivity associated with this unique bacterial Kdo inner core structure.