(+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-<(triisopropylsilyl)oxy>-6-octyne-2,4-diol

• 分子结构分类: 有机化合物 - 有机金属化合物 - 有机类金属化合物
• 英文名称: (+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-<(triisopropylsilyl)oxy>-6-octyne-2,4-diol
• 英文别名: (+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-[(triisopropylsilyl)oxy]-6-octyne-2,4-diol；(2R,3S,4S,5R)-3,5-dimethyl-1-tri(propan-2-yl)silyloxyoct-6-yne-2,4-diol
• 化学式: C₁₉H₃₈O₃Si
• 分子量: 342.594
• InChiKey: RZYSLCOQBCKOMG-YRXWBPOGSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  4.2
• 重原子数：
  23
• 可旋转键数：
  9
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.89
• 拓扑面积：
  49.7
• 氢给体数：
  2
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  (+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-<(triisopropylsilyl)oxy>-6-octyne-2,4-diol 在 palladium on activated charcoal 喹啉 、 氢气 作用下， 以 正己烷 为溶剂， 反应 6.0h， 生成 (+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-<(triisopropylsilyl)oxy>-6-octene-2,4-diol
  参考文献：
  名称：

  Stereochemistry of the iodocarbonatation of cis- and trans-3-methyl-4-pentene-1,2-diols: the unusual formation of several anti iodo carbonates

  摘要：

  A study on the stereoselective preparation of a series of 3-methyl-4,5-epoxy alcohols as an entry to polypropionates was undertaken. Initially, the opening of cis and trans TIPS-protected 2,3-epoxy butanols by propynyldiethylalane showed an excellent regioselectivity favoring the monoprotected 1,2-diol products. The resulting propargylic alcohols were stereoselectively reduced to the cis and trans 1-[(triisopropylsilyl)oxy]-3-methyl-4-hexen-2-ols. Iodocarbonatation of these four isomeric homoallylic alcohols was carried out and the stereochemistry of the intermediate iodo carbonates established. Interestingly, a complete anti selectivity (>20:1 anti:syn) was observed when both the syn 3-methyl and cis double-bond geometry were present (3b, 10, and 20). The anti relative configuration for all of the iodo carbonates was established by NMR, and that of 5b was confirmed by X-ray crystallography. This study demonstrated that the relative stereochemistry of the hydroxyl and C(3) methyl groups in combination with the cis or trans geometry of the alkene exerts a significant effect on the stereochemical outcome of the iodocarbonatation reaction. Methanolysis of the iodo carbonates produced the desired 3-methyl-4,5-epoxy alcohols. The application of this chemistry to the reiterative synthesis of polypropionates was carried out with epoxy alcohol 4a (anti isomer), producing a new homologated epoxy alcohol, 22, with six contiguous stereocenters in a highly stereoselective manner.

  DOI：

  10.1021/jo00073a027
• 作为产物：
  描述：

  (5R,6R)-4-(1-Iodo-ethyl)-5-methyl-6-triisopropylsilanyloxymethyl-[1,3]dioxan-2-one 在 甲醇 、 正丁基锂 、 triethylaluminum chloride 、 potassium carbonate 作用下， 反应 22.0h， 生成 (+/-)-(2R*,3S*,4S*,5R*)-3,5-Dimethyl-1-<(triisopropylsilyl)oxy>-6-octyne-2,4-diol
  参考文献：
  名称：

  Stereochemistry of the iodocarbonatation of cis- and trans-3-methyl-4-pentene-1,2-diols: the unusual formation of several anti iodo carbonates

  摘要：

  A study on the stereoselective preparation of a series of 3-methyl-4,5-epoxy alcohols as an entry to polypropionates was undertaken. Initially, the opening of cis and trans TIPS-protected 2,3-epoxy butanols by propynyldiethylalane showed an excellent regioselectivity favoring the monoprotected 1,2-diol products. The resulting propargylic alcohols were stereoselectively reduced to the cis and trans 1-[(triisopropylsilyl)oxy]-3-methyl-4-hexen-2-ols. Iodocarbonatation of these four isomeric homoallylic alcohols was carried out and the stereochemistry of the intermediate iodo carbonates established. Interestingly, a complete anti selectivity (>20:1 anti:syn) was observed when both the syn 3-methyl and cis double-bond geometry were present (3b, 10, and 20). The anti relative configuration for all of the iodo carbonates was established by NMR, and that of 5b was confirmed by X-ray crystallography. This study demonstrated that the relative stereochemistry of the hydroxyl and C(3) methyl groups in combination with the cis or trans geometry of the alkene exerts a significant effect on the stereochemical outcome of the iodocarbonatation reaction. Methanolysis of the iodo carbonates produced the desired 3-methyl-4,5-epoxy alcohols. The application of this chemistry to the reiterative synthesis of polypropionates was carried out with epoxy alcohol 4a (anti isomer), producing a new homologated epoxy alcohol, 22, with six contiguous stereocenters in a highly stereoselective manner.

  DOI：

  10.1021/jo00073a027

文献信息

• Regioselective cleavage of 3,4-epoxy alcohols with substituted alkynylaluminum reagents: application to the stereoselective synthesis of polypropionates
  作者：Wilnelia Dávila、Wildeliz Torres、José A. Prieto

  DOI：10.1016/j.tet.2007.05.122

  日期：2007.8

  reaction of 3-O-substituted propynyl aluminum reagents with a TIPS-protected 2,3-epoxy alcohol and several diastereomeric 2-methyl-3,4-epoxy alcohols offers a convenient synthetic approach for the subsequent preparation and epoxidation of allylic alcohols. The yields are low to moderate and the regioselectivity (internal vs external attack) similar to that of the standard diethylpropynyl aluminum reagent

  3-O-取代的丙炔基铝试剂与 TIPS 保护的 2,3-环氧醇和几种非对映异构 2-甲基-3,4-环氧醇的反应为烯丙醇的后续制备和环氧化提供了一种方便的合成方法。产率低至中等，区域选择性（内部与外部攻击）与标准二乙基丙炔基铝试剂相似。TMS-乙炔丙烷试剂提高了产率和良好的区域选择性，是受阻环氧化物裂解的首选试剂。这种有吸引力的方法被应用于两个先进的聚丙酸酯前体片段的制作。
• Regioselective cleavage of cis- and trans-2-methyl-3,4-epoxy alcohols with diethylpropynyl aluminum
  作者：Raymond Tirado、Gerardo Torres、Wildeliz Torres、José A. Prieto

  DOI：10.1016/j.tetlet.2004.12.018

  日期：2005.1

  The regioselectivity of the reaction of diethylpropynyl aluminum with diastereomeric 2-methyl-3-4-epoxy alcohols was studied. The preferred side of attack (1,3-diol vs 1,4-diol product) depends on the stereochemical disposition of the substituents. NMR studies showed that the regiochemistry of this reaction is governed by the aluminum coordination pattern. Protection of the alcohol with MEM provides the 1,3-diol product in systems where the free alcohol produced the 1,4-diols. (C) 2004 Elsevier Ltd. All rights reserved.