(R)-(-)-2-isopropyl-5-methylhex-5-enal | 212620-36-5

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: (R)-(-)-2-isopropyl-5-methylhex-5-enal
• 英文别名: (2R)-5-methyl-2-propan-2-ylhex-5-enal
• CAS: 212620-36-5
• 化学式: C₁₀H₁₈O
• 分子量: 154.252
• InChiKey: KQHKCWXITYVPCH-JTQLQIEISA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.1
• 重原子数：
  11
• 可旋转键数：
  5
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.7
• 拓扑面积：
  17.1
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为反应物：
  描述：

  (R)-(-)-2-isopropyl-5-methylhex-5-enal 在 二甲基氯化铝 作用下， 以 正己烷 、 二氯甲烷 为溶剂， 反应 0.5h， 以80%的产率得到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-en-1-ol 在 草酰氯 、 二甲基亚砜 、 三乙胺 作用下， 以 二氯甲烷 为溶剂， 反应 0.5h， 以71%的产率得到(R)-(-)-2-isopropyl-5-methylhex-5-enal
  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

• Asymmetric synthesis and Lewis acid mediated type II carbonyl ene cyclisations of (R)-2-isopropyl-5-methylhex-5-enal
  作者：D.Christopher Braddock、John M Brown

  DOI：10.1016/s0957-4166(00)00316-5

  日期：2000.9

  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.