(R)-(+)-2-isopropyl-5-methylhex-5-en-1-ol | 264258-71-1

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 脂肪酰基
• 英文名称: (R)-(+)-2-isopropyl-5-methylhex-5-en-1-ol
• 英文别名: (R)-2-Isopropyl-5-methylhex-5-en-1-ol；(2R)-5-methyl-2-propan-2-ylhex-5-en-1-ol
• CAS: 264258-71-1
• 化学式: C₁₀H₂₀O
• 分子量: 156.268
• InChiKey: GUSWYVGQDJWWCF-JTQLQIEISA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.2
• 重原子数：
  11
• 可旋转键数：
  5
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.8
• 拓扑面积：
  20.2
• 氢给体数：
  1
• 氢受体数：
  1

反应信息

• 作为反应物：
  描述：

  (R)-(+)-2-isopropyl-5-methylhex-5-en-1-ol 在 草酰氯 、 二甲基氯化铝 、 二甲基亚砜 、 三乙胺 作用下， 以 正己烷 、 二氯甲烷 为溶剂， 反应 1.0h， 生成 cis-2-isopropyl-5-methylenecyclohexanol
  参考文献：
  名称：

  Asymmetric synthesis and Lewis acid mediated type II carbonyl ene cyclisations of (R)-2-isopropyl-5-methylhex-5-enal

  摘要：

  The asymmetric synthesis of (R)-2-isopropyl-5-methylhex-5-enal in 98% ee is described. It was discovered that the key alkylation step employing an Evans chiral auxiliary and 3-methylbut-3-en-1-yl trifluoromethanesulphonate as the alkylating agent led to significant competing O-alkylation, a phenomenon not previously reported. Type II carbonyl ene cyclisation of the aldehyde with a range of Lewis acids led to either the (R,R)- or (R,S)-5-methylidenecyclohexanols without concurrent racemisation of the alpha stereogenic centre of the aldehyde. Conditions for effecting the easy racemisation of a model enantiomerically pure aldehyde, (S)-2-methylbutanal, were developed. In an effort to secure a dynamic kinetic resolution procedure, these conditions were applied to (R)-2-isopropyl-5-methylhex-5-enal. However, a competing and dominant Prins cyclisation occurred instead leading to a mixture of all possible cycloadducts, all of which were obtained in 98% ee. Any unreacted aldehyde was found to be enantiomerically pure. (C) 2000 Elsevier Science Ltd. All rights reserved.

  DOI：

  10.1016/s0957-4166(00)00316-5
• 作为产物：
  描述：

  (R)-(+)-2-isopropyl-5-methylhex-5-ene-1-carboxylic acid 在 lithium aluminium tetrahydride 作用下， 以 乙醚 为溶剂， 反应 1.0h， 以98%的产率得到(R)-(+)-2-isopropyl-5-methylhex-5-en-1-ol
  参考文献：
  名称：

  Asymmetric synthesis and Lewis acid mediated type II carbonyl ene cyclisations of (R)-2-isopropyl-5-methylhex-5-enal

  摘要：

  The asymmetric synthesis of (R)-2-isopropyl-5-methylhex-5-enal in 98% ee is described. It was discovered that the key alkylation step employing an Evans chiral auxiliary and 3-methylbut-3-en-1-yl trifluoromethanesulphonate as the alkylating agent led to significant competing O-alkylation, a phenomenon not previously reported. Type II carbonyl ene cyclisation of the aldehyde with a range of Lewis acids led to either the (R,R)- or (R,S)-5-methylidenecyclohexanols without concurrent racemisation of the alpha stereogenic centre of the aldehyde. Conditions for effecting the easy racemisation of a model enantiomerically pure aldehyde, (S)-2-methylbutanal, were developed. In an effort to secure a dynamic kinetic resolution procedure, these conditions were applied to (R)-2-isopropyl-5-methylhex-5-enal. However, a competing and dominant Prins cyclisation occurred instead leading to a mixture of all possible cycloadducts, all of which were obtained in 98% ee. Any unreacted aldehyde was found to be enantiomerically pure. (C) 2000 Elsevier Science Ltd. All rights reserved.

  DOI：

  10.1016/s0957-4166(00)00316-5

文献信息

• Kinetic resolution of primary 2-methyl-substituted alcohols via Pseudomonas cepacia lipase-catalysed enantioselective acylation
  作者：Ove Nordin、Ba-Vu Nguyen、Carin Vörde、Erik Hedenström、Hans-Erik Högberg

  DOI：10.1039/a908023f

  日期：——

  The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E < 10), 2-methyl-4-(2-thienyl)butan-1-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-1-ol (E = 3.2) and 2-methyl-6-(2-thienyl)hexan-1-ol (E = 3.8).

  研究了来自洋葱伯克霍尔德菌（PSeudomonas cepacia）的脂肪酶（如PFL、Amano PS等）在对一系列一级2-甲基取代醇使用乙酸乙烯酯作为酰基供体进行有机溶剂中的转酯化反应时的对映选择性。在对映选择性方面，最佳结果出现在3-芳基-2-甲基丙-1-醇中，大多数情况下对映体比例（E值）超过100，而其他3-取代的一级2-甲基丙-1-醇通常显示出较低的对映选择性：3-环烷基-2-甲基丙-1-醇（E ≈ 20）和2-甲基烷-1-醇（E ≈ 10）。将芳基团更靠近或远离手性中心会导致低对映选择性：2-芳基丙-1-醇（E < 10）、2-甲基-4-（2-噻吩基）丁-1-醇（E = 12）、2-甲基-5-（2-噻吩基）戊-1-醇（E = 3.2）和2-甲基-6-（2-噻吩基）己-1-醇（E = 3.8）。
• Enantioselective Synthesis of 2-Substituted Alcohols Using (+)-(1<i>S</i>,2<i>S</i>)-Pseudoephedrine as Chiral Auxiliary
  作者：Lutz Tietze、Christian Raith、C. Brazel、Sören Hölsken、Jörg Magull

  DOI：10.1055/s-2008-1000851

  日期：2008.1

  An improved method for the selective synthesis of enantiopure 2-substituted alcohols is described. Highly diastereoselective alkylation of pseudoephedrine-derived amides and subsequent oxidation of the hydroxyl group in the amide side chain, leads to oxoamides. These oxoamides can be purified by crystallization or preparative HPLC to obtain diastereomeric ratios of >99:1. The following reductive cleavage of the modified auxiliary allows the epimerization-free formation of enantiopure 2-substituted alcohols with up to 99.9% ee.

  本研究介绍了一种选择性合成对映体纯 2-取代醇的改进方法。对来源于伪麻黄碱的酰胺进行高非对映选择性烷基化，然后氧化酰胺侧链中的羟基，从而得到草酰胺。这些草酰胺可通过结晶或制备型高效液相色谱法进行提纯，以获得大于 99:1 的非对映比率。随后对改性助剂进行还原裂解，可形成无对映异构的 2-取代醇，ee 值高达 99.9%。