| 韩小见,王佳佳,万玥,赵云燕,赵炜.化学通报,2015,78(7):644-649. |
| 不同溶剂中氟原子对糖苷键立体选择性的影响 |
| Exploring the influence of fluorine atoms on glycosylation in different solvents |
| 投稿时间：2014-11-14 修订日期：2014-12-27 |
| DOI： |
| 中文关键词: 2-氟苄基 溶剂效应 立体选择性 糖苷键 |
| 英文关键词:2-fluorobenzyl protection, solvent effects, stereoselective, glycosidic bond |
| 基金项目:国家自然科学基金项目 |
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| 中文摘要: |
| 本文探究了2,3,4-O-三苄基-6-O-(2-氟苄基)-β -对甲基苯基-D-葡萄糖硫苷9作为糖基化供体,甲醇作为受体,并以糖基化供体2,3,4,6-O-四苄基-β -对甲基苯基-D-葡萄糖硫苷5为对照,在乙腈等五种不同溶剂中进行糖基化反应,以此探索葡萄糖硫苷在C-6位引入氟取代基对糖苷键立体选择性的影响。研究结果表明,引入的2-氟苄基与普通苄基保护基相比,β构型比例都有一定的提高,其中当溶剂为乙腈时,β构型比例较其他溶剂提升最明显,α/β比值可达到1/4.7。 |
| 英文摘要: |
| Based on 2,3,4-tri-O-benzyl-6-O-(2-fluoro-benzyl)-β-p-methylphenyl-1-thio-D-glucopyranoside 9 as glycosyl donor, glycosylation reactions were carried out in five different solvents, and compared with glycosyl donor 2,3,4,6-O-tetra benzyl-p-methylphenyl-1-thio-D-glucopyranoside 5 methanol as acceptor. It was proposed that 2-fluorine benzyl protecting C-6 of glycosyl donor contributed to glycosyl acceptors attacking from the β-face to selectively afford 1, 2-trans glycosidic bond. Especially, the α/β ratio (1/4.7) has been improved comparing with ordinary benzyl protecting group when the solvent of glycosylation was acetonitrile. The possible mechanism was proposed that the forming H-bond of fluorine with glycosyl acceptor and axial α-nitrilium ion leaded to the predominant formation of β-products by glycosyl acceptors attacking from the β–face. |
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