Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10605619 | Carbohydrate Research | 2011 | 8 Pages |
Abstract
Glycosylation studies for the construction of 1,2-cis α-linkages with O-(2,3,5,6-tetra-O-benzyl-β-d-galactofuranosyl) trichloroacetimidate (1) and several acceptors, including d-mannosyl and l-rhamnosyl derivatives were performed. The reactions were conducted at low temperatures using CH2Cl2, Et2O, and acetonitrile as solvents. A non-participating solvent such as CH2Cl2 at â78 °C, favored the α-d-configuration. In contrast, acetonitrile strongly favored the β-d-configuration, whereas no selectivities were observed with Et2O. The use of thiophene as an additive did not enhance the α-d-selectivity as in the pyranose counterpart. Although selectivities strongly depended on the acceptor, trichloroacetimidate 1 constitutes a valuable donor for the synthesis of α-d-Galf-(1â2)-l-Rha and α-d-Galf-(1â6)-d-Man. As these motifs are present in pathogenic microorganisms, these procedures described here are useful for the straightforward synthesis of natural oligosaccharides.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Gabriel Gola, Mariano J. Tilve, Carola Gallo-Rodriguez,