Matched and mismatched acceptor/donor pairs in the glycosylation of a trisaccharide diol free at O-3 of two N-acylated glucosamine residues.

Autor: Guillemineau M; Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1., Auzanneau FI
Jazyk: angličtina
Zdroj: Carbohydrate research [Carbohydr Res] 2012 Aug 01; Vol. 357, pp. 132-8. Date of Electronic Publication: 2012 May 26.
DOI: 10.1016/j.carres.2012.04.020
Abstrakt: Reciprocal donor acceptor selectivity (RDAS) and double diastereodifferentiation are two concepts that have been used to explain how a glycosyl acceptor and donor may be 'matched' or 'mismatched' in glycosylation reactions. We describe here how the α-L-fucosylation and β-D-galactosylation of a trisaccharide displaying two equatorial OH groups at C-3 of N-acylated glucosamine units led to different regioselectivities or different 'matched' pairs. These results may be explained under the reciprocal donor acceptor selectivity or double diastereodifferentiation concepts. We also suggest a third explanation to these results: the presence of a benzylidene at the nonreducing end acceptor led to rigidity at this residue which resulted into a mismatched pair during β-D-galactosylation but allowed α-L-fucosylation.
(Copyright © 2012 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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