Abstract
Pyranosides with 2,3-trans carbamate groups exhibit high 1,2-cis selectivity in glycosylation reactions. Using glycosyl donors with N-benzyl 2,3-trans carbamate groups, an anti-Helicobacter pylori oligosaccharide was synthesized in an efficient manner. Moreover, pyranosides with 2,3-trans carbamate groups readily undergo anomerization from the β to the α configuration under mild acidic conditions via endocyclic cleavage. Acyclic cations generated during the endocyclic cleavage reaction were captured using reduction and intramolecular Friedel-Crafts reaction. By exploiting this anomerization, multiply aligned 1,2-trans glycosyl bonds can be transformed to 1,2-cis glycosyl bonds in a single operation. The 1,2-cis selective preparation of aminoglycosides is crucial for biologically active oligosaccharides. Glycosyl donors containing the N-benzyl 2,3-trans carbamate group for 1,2-cis selective glycosylation were developed and used to prepare an anti-Helicobacter pylori oligosaccharide in an efficient manner. In addition, pyranosides containing the N-acetyl 2,3-trans carbamate group were found to be easily anomerized under mild acidic conditions. The anomerization occurred through endocyclic cleavage, and the generated acyclic cation was captured. Multiple existing 1,2-trans glycosyl bonds were changed to the 1,2-cis form in a single step involving endocyclic cleavage.
Original language | English |
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Pages (from-to) | 502-515 |
Number of pages | 14 |
Journal | Chemical Record |
Volume | 14 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2014 Jun |
Externally published | Yes |
Keywords
- anomerization
- carbohydrates
- endocyclic cleavage
- glycosylation
- oligosaccharides
ASJC Scopus subject areas
- Chemistry(all)
- Biochemistry
- Chemical Engineering(all)
- Materials Chemistry