Venturing beyond Donor-Controlled Glycosylation: New Perspectives toward Anomeric Selectivity

Area of Science:

• Carbohydrate Chemistry
• Organic Synthesis
• Glycobiology

Background:

• Glycans are vital biomolecules involved in numerous biological processes.
• The structural diversity and complexity of glycans hinder their isolation and study.
• Glycochemistry offers synthetic alternatives for obtaining pure glycans.

Purpose of the Study:

• To present advancements in glycochemistry beyond conventional donor-controlled strategies.
• To emphasize mechanistic explanations for anomeric selectivity in glycosylation.
• To provide perspectives for a unified strategy in glycan synthesis.

Main Methods:

• Exploration of unsaturated glycosyl donors and their role in transition metal catalysis.
• Investigation of glycosyl acceptors' influence on stereocontrol, including nucleophilicity and pKa.
• Development of stereoselective catalysts as efficient alternatives to stoichiometric reagents.
• Implementation of transient masking groups and one-pot strategies to enhance synthetic efficiency.

Main Results:

• New glycosylation strategies using unsaturated donors reduce protection/deprotection steps.
• Glycosyl acceptors demonstrate significant tunability for controlling stereoselectivity.
• Stereoselective catalysts offer a greener approach to controlling glycosylation outcomes.
• Streamlined synthetic approaches improve the efficiency and practicality of oligosaccharide synthesis.

Conclusions:

• Recent advancements provide powerful tools for stereoselective glycan synthesis.
• Understanding the interplay of donors, acceptors, and catalysts is crucial for optimizing glycosylation.
• Further development of unified strategies is needed for the comprehensive synthesis of diverse glycans.