methyl 2,3,4-tri-O-benzyl-6-O-(2,3,4,6-tetra-O-benzyl-α-D-gulopyranosyl)-α-D-glucopyranoside | 1163254-51-0

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: methyl 2,3,4-tri-O-benzyl-6-O-(2,3,4,6-tetra-O-benzyl-α-D-gulopyranosyl)-α-D-glucopyranoside
• 英文别名: Bn(-2)[Bn(-3)][Bn(-4)][Bn(-6)]Gul(a1-6)[Bn(-2)][Bn(-3)][Bn(-4)]a-Glc1Me；(2S,3R,4S,5R,6R)-2-methoxy-3,4,5-tris(phenylmethoxy)-6-[[(2S,3R,4R,5S,6R)-3,4,5-tris(phenylmethoxy)-6-(phenylmethoxymethyl)oxan-2-yl]oxymethyl]oxane
• CAS: 1163254-51-0
• 化学式: C₆₂H₆₆O₁₁
• 分子量: 987.199
• InChiKey: FLOIPOSVHDNCRB-OVGTXPBJSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  9.5
• 重原子数：
  73
• 可旋转键数：
  26
• 环数：
  9.0
• sp3杂化的碳原子比例：
  0.32
• 拓扑面积：
  102
• 氢给体数：
  0
• 氢受体数：
  11

反应信息

• 作为产物：
  描述：

  甲基2,3,4-三-O-苄基-α-D-吡喃葡萄糖苷 、 phenyl 2,3,4,6-tetra-O-benzyl-1-thio-β-D-gulopyranoside 在 三氟甲磺酸酐 、 二苯基亚砜 作用下， 以 二氯甲烷 为溶剂， 生成 methyl 2,3,4-tri-O-benzyl-6-O-(2,3,4,6-tetra-O-benzyl-β-D-gulopyranosyl)-α-D-glucopyranoside 、 methyl 2,3,4-tri-O-benzyl-6-O-(2,3,4,6-tetra-O-benzyl-α-D-gulopyranosyl)-α-D-glucopyranoside
  参考文献：
  名称：

  氧杂碳鎓离子构象异构体对糖基化的立体化学结果的影响。

  摘要：

  立体选择性糖基化反应的研究已经占据了合成碳水化合物化学家的数十年。传统上，大多数注意力都集中在控制异头离去基团的S（N）2取代上，如Lemieux的原位异构化方案和发现异头三氟甲磺酸酯作为β-甘露糖苷立体选择性形成中的反应性中间体所强调的那样。近来，已经清楚的是，类似S（N）1的反应途径也可以导致高度选择性的糖基化反应。这篇综述描述了立体选择性糖基化的一些最新实例，其中氧杂碳鎓离子被认为是选择性的基础。

  DOI：

  10.1016/j.carres.2010.02.027

文献信息

• Stereodirecting Effect of the Pyranosyl C-5 Substituent in Glycosylation Reactions
  作者：Jasper Dinkelaar、Ana Rae de Jong、Robert van Meer、Mark Somers、Gerrit Lodder、Herman S. Overkleeft、Jeroen D. C. Codée、Gijsbert A. van der Marel

  DOI：10.1021/jo900662v

  日期：2009.7.17

  The stereodirecting effect of the glycosyl C-5 substituent has been investigated in a series of D-pyranosyl thioglycoside donors and related to their preferred positions in the intermediate H-3(4) and H-4(3) half-chair oxacarbenium ions. Computational studies showed that an axially positioned C-5 carboxylate ester can stabilize the (3)H4 half-chair oxacarbenium ion conformer by donating electron densit from its carbonyl function into the electron-poor oxacarbenium ion functionality. A similar stabilization can be achieved by a C-5 benzyloxyrnethyl group, but,the magnitude of this stabilization is significantly smaller than for the C-5 carboxylate ester. As a result, the preference of the C-5 benzyloxymethyl to occupy an axial position in the half-chair oxacarbenium ions is much reduced compared to the C-5 carboxylate ester. To minimize steric interactions, a C-5 methyl group prefers to adopt an equatorial position and therefore favors the H-4(3) half-chair oxacarbenium ion. When all pyranosyl substituents occupy their favored position in one of the two intermediate half-chair oxacarbenium ions, highly stereoselective glycosylations can be achieved as revealed by the excellent beta-selectivity of mannuronate esters and alpha-selectivity of 6-deoxygulosides.
• The impact of oxacarbenium ion conformers on the stereochemical outcome of glycosylations
  作者：Marthe T.C. Walvoort、Jasper Dinkelaar、Leendert J. van den Bos、Gerrit Lodder、Herman S. Overkleeft、Jeroen D.C. Codée、Gijsbert A. van der Marel

  DOI：10.1016/j.carres.2010.02.027

  日期：2010.7

  The search for stereoselective glycosylation reactions has occupied synthetic carbohydrate chemists for decades. Traditionally, most attention has been focused on controlling the S(N)2-like substitution of anomeric leaving groups as highlighted by Lemieux's in situ anomerization protocol and by the discovery of anomeric triflates as reactive intermediates in the stereoselective formation of beta-mannosides

  立体选择性糖基化反应的研究已经占据了合成碳水化合物化学家的数十年。传统上，大多数注意力都集中在控制异头离去基团的S（N）2取代上，如Lemieux的原位异构化方案和发现异头三氟甲磺酸酯作为β-甘露糖苷立体选择性形成中的反应性中间体所强调的那样。近来，已经清楚的是，类似S（N）1的反应途径也可以导致高度选择性的糖基化反应。这篇综述描述了立体选择性糖基化的一些最新实例，其中氧杂碳鎓离子被认为是选择性的基础。