Rationally designed syntheses of high-mannose and complex type undecasaccharides

Area of Science:

• Carbohydrate Chemistry
• Glycoscience
• Organic Synthesis

Background:

• Undecassacharides are complex carbohydrates with significant biological roles.
• The synthesis of specific glycan structures, like high-mannose and complex-type oligosaccharides, is crucial for glycobiology research.
• Sialic acid residues play key roles in biological recognition events.

Purpose of the Study:

• To develop synthetic routes for a high-mannose type triantennary undecasaccharide (1).
• To synthesize a completely protected complex-type biantennary undecasaccharide (2) featuring alpha-(2-->3)-linked sialic acid residues.
• To establish methodologies for regio- and stereo-selective glycosylation in complex carbohydrate synthesis.

Main Methods:

• Regio- and stereo-selective mannosylation using protected mannosyl donors.
• Stepwise chain elongation of core pentasaccharides.
• Glycosylation coupling reactions between protected oligosaccharide fragments.
• Deprotection strategies to yield final target structures.

Main Results:

• Successful synthesis of the high-mannose type triantennary undecasaccharide (1).
• Synthesis of a protected complex-type biantennary undecasaccharide (2) with specific sialic acid linkages.
• Demonstration of efficient methods for constructing complex glycan architectures.

Conclusions:

• The described synthetic routes provide access to important undecasaccharide structures.
• The methodologies employed are applicable to the synthesis of other complex glycans.
• This work contributes to the field of synthetic glycobiology and glycan-based therapeutics.