ethyl 2,6-di-O-pivaloyl-3,4-O-isopropylidene-β-D-galactothiopyranoside | 256449-12-4

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: ethyl 2,6-di-O-pivaloyl-3,4-O-isopropylidene-β-D-galactothiopyranoside
• 英文别名: [(3aS,4R,6S,7R,7aS)-7-(2,2-dimethylpropanoyloxy)-6-ethylsulfanyl-2,2-dimethyl-4,6,7,7a-tetrahydro-3aH-[1,3]dioxolo[4,5-c]pyran-4-yl]methyl 2,2-dimethylpropanoate
• CAS: 256449-12-4
• 化学式: C₂₁H₃₆O₇S
• 分子量: 432.579
• InChiKey: UUIAOOPEPAKBGI-CWVYHPPDSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  4.1
• 重原子数：
  29
• 可旋转键数：
  9
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.9
• 拓扑面积：
  106
• 氢给体数：
  0
• 氢受体数：
  8

反应信息

• 作为产物：
  描述：

  三甲基乙酰氯 、 4-氯苯甲酰氯 、 ethyl 3,4-O-isopropylidene-1-thio-β-D-galactopyranoside 在 4-二甲氨基吡啶 作用下， 以 吡啶 为溶剂， 以41%的产率得到ethyl 2,6-di-O-pivaloyl-3,4-O-isopropylidene-β-D-galactothiopyranoside
  参考文献：
  名称：

  Acyl Transfer as a Problematic Side Reaction in Polymer-Supported Oligosaccharide Synthesis

  摘要：

  Under a wide variety of glycosylation conditions acyl transfer to the polymer support competed with glycoside formation, including the pivaloyl protecting group. As well as acyl transfer, many glycosylations also led to the formation of polymer-bound beta-1,2-linked oligomers of the donor. Using ethyl 2,6-di-O-pivaloyl-3,w4-O-isopropylidene-beta-D-galactothiopyranoside as donor under promotion of N-iodosuccinimide/silver trifluoromethanesulfonate in the presence of 2-methyl-2-butene, an 82% yield of glycoside was obtained along with pivaloylated polymer. Subsequent work showed that increasing the steric bulk about the alcoholic acceptor in conjunction with this 2-O-pivaloyl-protected glycosyl donor completely suppresses this side reaction, giving a nearly quantitative yield of glycoside. This contraintuitive approach of decreasing the reactivity of both the donor and the acceptor to minimize a side reaction is rationalized by assuming that the barrier to acyl transfer is more sensitive to the protecting groups than that of glycosylation. These developments led to a polymer-supported synthesis of the branch point trisaccharide of the group B type 1A Streptococcus capsular polysaccharide.

  DOI：

  10.1021/jo990712b

文献信息

• Acyl Transfer as a Problematic Side Reaction in Polymer-Supported Oligosaccharide Synthesis
  作者：Tomoo Nukada、Attila Berces、Dennis M. Whitfield

  DOI：10.1021/jo990712b

  日期：1999.12.1

  Under a wide variety of glycosylation conditions acyl transfer to the polymer support competed with glycoside formation, including the pivaloyl protecting group. As well as acyl transfer, many glycosylations also led to the formation of polymer-bound beta-1,2-linked oligomers of the donor. Using ethyl 2,6-di-O-pivaloyl-3,w4-O-isopropylidene-beta-D-galactothiopyranoside as donor under promotion of N-iodosuccinimide/silver trifluoromethanesulfonate in the presence of 2-methyl-2-butene, an 82% yield of glycoside was obtained along with pivaloylated polymer. Subsequent work showed that increasing the steric bulk about the alcoholic acceptor in conjunction with this 2-O-pivaloyl-protected glycosyl donor completely suppresses this side reaction, giving a nearly quantitative yield of glycoside. This contraintuitive approach of decreasing the reactivity of both the donor and the acceptor to minimize a side reaction is rationalized by assuming that the barrier to acyl transfer is more sensitive to the protecting groups than that of glycosylation. These developments led to a polymer-supported synthesis of the branch point trisaccharide of the group B type 1A Streptococcus capsular polysaccharide.