α and β l-Fucopyranosyl oxyamines: key intermediates for the preparation of fucose-containing glycoconjugates by oxime ligation
- 作者：Vincent Dulé ; ry ; Olivier Renaudet ; Christian Philouze ; Pascal Dumy
- 关键词：Aminoxylated fucopyranosyl ; Glycosylation ; Anomeric mixture ; Oxime ligation ; Crystal structure ; Glycocluster
- 刊名：Carbohydrate Research
- 出版年：2007
- 期刊代码：15_00086215
- 类别：ch
- 出版时间：21 May 2007
- 卷：342
- 期：7
- 页码：894-900
- 文件大小：218 K
摘要
We report herein the synthesis of new α and β aminooxylated l-fucopyranosyl derivatives for the preparation of glycoclusters through oxime ligation. The glycosylation reaction between activated triacetylated l-fucopyranosyl fluoride and N-hydroxyphthalimide was carried out in the presence of boron trifluoride–diethyl etherate and the stereochemical outcome of glycosylation was compared in dichloromethane, acetonitrile or tetrahydrofuran. Interestingly, an unexpected α and β anomer ratio was obtained in spite of the presence of an acetate participating group at the carbon 2, particularly the 1,2-cis glycosylation was largely favoured in acetonitrile. The resulting α and β N-oxyphthalimido fucopyranosyl derivatives were finally deprotected with methylhydrazine to obtain the corresponding free aminooxylated fucopyranosyls. The structure of single-crystal α anomer 12 was analysed by X-ray diffraction.