Influence of protecting groups on O- and C-glycosylation with neuraminyl and ulosonyl dibutylphosphates.

Autor: Ogasahara R; Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA; Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan., Abdullayev S; Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA; Department of Chemistry, Université Claude Bernard Lyon 1, Domaine Scientifique de la Doua, boulevard du 11 Novembre 1918, 69622, Villeurbanne Cedex, France., Sarpe VA; Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA, 30602, United States; Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602, United States., Mandhapati AR; Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA., Crich D; Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA; Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA, 30602, United States; Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602, United States; Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA, 30602, United States. Electronic address: david.crich@uga.edu.
Jazyk: angličtina
Zdroj: Carbohydrate research [Carbohydr Res] 2020 Oct; Vol. 496, pp. 108100. Date of Electronic Publication: 2020 Jul 28.
DOI: 10.1016/j.carres.2020.108100
Abstrakt: The adamantanyl thioglycosides of 5-isothiocyano and 5-azido 5-desamino-4,7,8,9-tetra-O-acetylneuraminic acid methyl ester were converted into the corresponding dibutyl phosphates, which proved to be excellent α-selective donors for O-sialidation with a range of typical acceptors, and good donors for reaction with allyltributylstannane, albeit without significant anomeric selectivity. In the KDN series the dibuylphosphate derived from a donor carrying a 4,5-cyclic carbonate protecting group afforded the corresponding C-glycoside with excellent α-selectivity on activation in the presence of allyltributylstannane, whereas the corresponding donor carrying acetate esters at the 4- and 5-positions was unselective. Overall, it is revealed that while the strongly electron-withdrawing isothiocyanato and azido groups are sufficient to promote highly α-selective O-sialidation, they are inadequate when faced with less reactive nucleophiles when mixtures of anomers are obtained.
(Copyright © 2020 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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