UCD School of Chemistry & Chemical Biology

Glycosyl thiol chemistry
Glycosyl thiols are the key building blocks for the construction of various thiooligosaccharides and S-glycoconjugates. We have developed a direct and stereospecific method for the synthesis of α-glycosyl thiols by ring-opening of 1,6-anhydrosugars with bis(trimethylsilyl)sulfide. This procedure is a significant advance in glycosyl thiol chemistry because there have not been any reports on direct stereoselective preparation of α-glycosyl thiols prior to our work. Extended studies on the scope of the procedure are currently underway.

New glycosylation method
We have dedicated to developing new methodologies for carbohydrate synthesis, including development of new glycosyl donors and methods for the synthesis of 1,2-cis glycofuranosides. A new class of glycosyl thioimidates, S-glycosyl N-phenyl trifluoroacetimidates, has been developed as glycosylating agents in our laboratory. These thioimidates can be easily prepared and activated effectively with catalytic amounts of Lewis acid. Studies on the application of this new glycosylation method to specific carbohydrate targets and development of other novel glycosyl donors are in progress.





Synthesis of S-glycoconjugates
Glycoconjugates play a key role in numerous cell-cell recognition and interaction processes. Their thioglycoside analogues have thus often become the synthetic targets due to the enhanced chemical stability and enzymatic resistance. We have achieved the first total synthesis of a thioglycoside analogue of the immunostimulant KRN7000, which is a lead compound for the treatment of many diseases including cancer, diabetes, malaria and hepatitis B. We are now optimizing the synthetic route and applying it to the synthesis of other thioglycoside analogues.