640
3
Chemical Glycosylation Reactions
5.6 Synthesis of Oligosaccharides Based on BC Glycosyl Donors
The CB glycoside methodology by means of the “latent” BCB (or ACB) glycoside and the
“active” CB glycoside has proved itself as a reliable method for the synthesis of complex
oligosaccharides.
5.6.1 Synthesis of Trisaccharide 431, the Repeat Unit of the O-Antigen
Polysaccharide from Danish Helicobacter pylori Strains
Kim and co-workers synthesized the repeat unit of the O-antigen polysaccharide from Danish Helicobacter pylori strains, 431 ( > Scheme 69) [214]. Coupling of donor CB L-rhamnoside 427 and acceptor BCB D-rhamnoside 428 gave α-disaccharide 429a in 88% yield. Selective hydrogenolysis of “latent” BCB disaccharide afforded “active” CB disaccharide 429b in
⊡ Scheme 70
Synthesis of tetrasaccharide 438
3
Chemical Glycosylation Reactions
5.6 Synthesis of Oligosaccharides Based on BC Glycosyl Donors
The CB glycoside methodology by means of the “latent” BCB (or ACB) glycoside and the
“active” CB glycoside has proved itself as a reliable method for the synthesis of complex
oligosaccharides.
5.6.1 Synthesis of Trisaccharide 431, the Repeat Unit of the O-Antigen
Polysaccharide from Danish Helicobacter pylori Strains
Kim and co-workers synthesized the repeat unit of the O-antigen polysaccharide from Danish Helicobacter pylori strains, 431 ( > Scheme 69) [214]. Coupling of donor CB L-rhamnoside 427 and acceptor BCB D-rhamnoside 428 gave α-disaccharide 429a in 88% yield. Selective hydrogenolysis of “latent” BCB disaccharide afforded “active” CB disaccharide 429b in
⊡ Scheme 70
Synthesis of tetrasaccharide 438