Rapid assembly of the doubly-branched pentasaccharide domain of the immunoadjuvant jujuboside A via convergent B(C6F5)3-catalyzed glycosylation of sterically-hindered precursors
| Autor: | David Y. Gin, Rashad R. Karimov, Derek S. Tan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Glycosylation Nitrile 010405 organic chemistry Chemistry Stereochemistry Glycosyl acceptor Metals and Alloys Convergent synthesis Disaccharide General Chemistry 010402 general chemistry 01 natural sciences Catalysis 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound Materials Chemistry Ceramics and Composites Trisaccharide Lewis acids and bases Glycosyl donor |
| Zdroj: | Chemical Communications. 53:5838-5841 |
| ISSN: | 1364-548X 1359-7345 |
| DOI: | 10.1039/c7cc01783a |
| Popis: | A convergent synthesis of the complex, doubly-branched pentasaccharide domain of the natural-product immunoadjuvant jujuboside A is described. The key step is a sterically-hindered glycosylation reaction between a branched trisaccharide trichloroacetimidate glycosyl donor and a disaccharide glycosyl acceptor. Conventional Lewis acids (TMSOTf, BF3·Et2O) were ineffective in this glycosylation, but B(C6F5)3 catalyzed the reaction successfully. Inherent complete diastereoselectivity for the undesired α-anomer was overcome by rational optimization with a nitrile solvent system (1:5 t-BuCN/CF3Ph) to provide flexible, effective access to the β-linked pentasaccharide. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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