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Nickel-catalyzed stereoselective glycosylation with C(2)-N-substituted benzylidene D-glucosamine and galactosamine trichloroacetimidates for the formation of 1,2-cis-2-amino glycosides. Applications to the synthesis of heparin disaccharides, GPI anchor pseudodisaccharides, and α-GalNAc.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Mensah, Enoch Akuamoah Nguyen, Hien M. |
| Copyright Year | 2010 |
| Abstract | The 1,2-cis-2-amino glycosides are key components found within a variety of biologically important oligosaccharides and glycopeptides. Although there are remarkable advances in the synthesis of 1,2-cis-2-amino glycosides, disadvantages of the current state-of-the-art methods include limited substrate scope, low yields, long reaction times, and anomeric mixtures. We have developed a novel method for the synthesis of 1,2-cis-2-amino glycosides via nickel-catalyzed α-selective glycosylation with C(2)-N-substituted benzylidene D-glucosamine and galactosamine trichloroacetimidates. These glycosyl donors are capable of coupling to a wide variety of alcohols to provide glycoconjugates in high yields with excellent levels of α-selectivity. Additionally, only a substoichiometric amount of nickel (5-10 mol %) is required for the reaction to occur at 25 °C. The current nickel method relies on the nature of the nickel-ligand complex to control the α-selectivity. The reactive sites of the nucleophiles or the nature of the protecting groups have little effect on the α-selectivity. This methodology has also been successfully applied to both disaccharide donors and acceptors to provide the corresponding oligosaccharides in high yields and α-selectivity. The efficacy of the nickel procedure has been further applied toward the preparation of heparin disaccharides, GPI anchor pseudodisaccharides, and α-GluNAc/GalNAc. Mechanistic studies suggest that the presence of the substituted benzylidene functionality at the C(2)-amino position of glycosyl donors is crucial for the high α-selectivity observed in the coupling products. Additionally, the α-orientation of the C(1)-trichloroacetimidate group on glycosyl donors is necessary for the coupling process to occur. |
| File Format | PDF HTM / HTML |
| DOI | 10.1021/ja106682m |
| Alternate Webpage(s) | https://nguyenresearchgroup.lab.uiowa.edu/sites/nguyenresearchgroup.lab.uiowa.edu/files/ja106682m.pdf |
| PubMed reference number | 20860359 |
| Alternate Webpage(s) | https://doi.org/10.1021/ja106682m |
| Journal | Medline |
| Volume Number | 132 |
| Issue Number | 40 |
| Journal | Journal of the American Chemical Society |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
