期刊
CARBOHYDRATE RESEARCH
卷 344, 期 13, 页码 1646-1653出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.carres.2009.06.004
关键词
Peracetyl-aldopyranoses; Glycosylation; Tin tetrachloride; Silver trifluoroacetate; 1,2-cis-Glycosides; 1,2-trans-Glycosides; Anomerization
资金
- Region Rhone-Alpes via MIRA Mobility Programme
- Ministry of Foreign Affairs
- University Claude-Bernard
Glycosidation of sugar peracetates (D-gluco, D-galacto) with SnCl4 and CF3CO2Ag led to either 1,2-cis-, or 1,2-trans-glycosides, depending primarily on the alcohols used. In particular, 1.2-trans-glycosides, expected from acyl-protected glycosyl donors, were formed in high yields with alcohols sharing specific features such as bulkiness, presence of electron-withdrawing groups or polyethoxy motifs. In contrast, simple alcohols afforded similar to 1:1 mixtures of 2,3,4,6-tetra-O-acetyl, and 3,4,6-tri-O-acetyl 1,2-cis-glycosides due to anomerization and/or acid-catalyzed fragmentation of 1,2-orthoester intermediates. After reacetylation or deacetylation, acetylated or fully deprotected 1,2-cis-glycosides (alpha-D-gluco, alpha-D-galacto) were obtained in similar to 90% yields by a simple and direct method. (C) 2009 Elsevier Ltd. All rights reserved.
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