2,2-dimethyl-3,6-heptadiene | 53786-96-2

• 分子结构分类: 有机化合物 - 碳氢化合物 - 不饱和烃
• 英文名称: 2,2-dimethyl-3,6-heptadiene
• 英文别名: 6.6-Dimethyl-heptadien-(1.4)；6,6-dimethyl-hepta-1,4-diene；6,6-dimethylhepta-1,4-diene
• CAS: 53786-96-2
• 化学式: C₉H₁₆
• 分子量: 124.226
• InChiKey: ZGJKAUXKGMEHQL-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.7
• 重原子数：
  9
• 可旋转键数：
  3
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.56
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为反应物：
  描述：

  2,2-dimethyl-3,6-heptadiene 在 lithium tert-butoxide 作用下， 以 乙醚 、 正己烷 为溶剂， 反应 0.5h， 生成 (+)-2-neopentylcyclopentanone
  参考文献：
  名称：

  Chiral Synthesis via Organoboranes. 48. Efficient Synthesis of Trans-Fused Bicyclic and Cyclic Ketones and Secondary Alcohols in High Optical Purities via Asymmetric Cyclic Hydroboration with Isopinocampheylchloroborane Etherate

  摘要：

  Highly stereo- and enantioselective annelation has been achieved for the synthesis of trans-fused bicyclic and cyclic ketones via the asymmetric cyclic hydroboration of suitable cyclic dienes, such as 1-allyl-1-cycloalkenes or 1-vinyl-1-cycloalkenes and appropriate acyclic 1,4-dienes, respectively, with enantiomerically pure isopinocampheylchloroborane etherate (IpcBHCl . Et2O). The IpcBHCl . Et2O (an 86-90% equilibrium mixture) was readily synthesized by the reaction of an equivalent amount of hydrochloric acid in ethyl ether (Et2O) with optically pure isopinocampheylborane (IpcBH(2)). The hydroboration of the terminal double bond of a representative diene with IpcBHCl . Et2O readily provided the corresponding isopinocampheylalkylchloroborane (IpcRBCl). Subsequent, hydridation of the IpcRBCl with lithium aluminum hydride (LAH, 0.25 equiv) at -20 or -25 degrees C generated the intermediate isopinocampheylalkylborane (IpcRBH) almost instantly, which then underwent a rapid stereospecific and enantioselective intramolecular cyclic hydroboration to provide the intermediate cyclic trialkylborane. This trialkylborane, on treatment with an aldehyde, liberated the optically pure auxiliary as a-pinene (readily recovered for recycle) to provide the corresponding cyclic borinate ester. This ester reacted smoothly with alpha,alpha-dichloromethyl methyl ether (DCME) in the presence of a hindered base (the DCME reaction) to yield, after oxidation with buffered hydrogen peroxide, the trans-fused bicyclic or cyclic ketone in high enantiomeric excess (ee). In another improved approach, in situ generated IpcBHCl . Et2O, from the reduction of isopinocampheyldichloroborane (IpcBCl(2)) with trimethylsilane (Me3SiH), in the presence of representative dienes in Et2O provided considerably improved optical yields of the bicyclic and cyclic ketones. The trialkylboranes obtained from suitable acyclic dienes can be easily protonolyzed to provide the secondary alcohols in high ee.

  DOI：

  10.1021/jo981040c

文献信息

• Chiral Synthesis via Organoboranes. 48. Efficient Synthesis of <i>Trans</i>-Fused Bicyclic and Cyclic Ketones and Secondary Alcohols in High Optical Purities via Asymmetric Cyclic Hydroboration with Isopinocampheylchloroborane Etherate
  作者：Ulhas P. Dhokte、Pradip M. Pathare、Verinder K. Mahindroo、Herbert C. Brown

  DOI：10.1021/jo981040c

  日期：1998.11.1

  Highly stereo- and enantioselective annelation has been achieved for the synthesis of trans-fused bicyclic and cyclic ketones via the asymmetric cyclic hydroboration of suitable cyclic dienes, such as 1-allyl-1-cycloalkenes or 1-vinyl-1-cycloalkenes and appropriate acyclic 1,4-dienes, respectively, with enantiomerically pure isopinocampheylchloroborane etherate (IpcBHCl . Et2O). The IpcBHCl . Et2O (an 86-90% equilibrium mixture) was readily synthesized by the reaction of an equivalent amount of hydrochloric acid in ethyl ether (Et2O) with optically pure isopinocampheylborane (IpcBH(2)). The hydroboration of the terminal double bond of a representative diene with IpcBHCl . Et2O readily provided the corresponding isopinocampheylalkylchloroborane (IpcRBCl). Subsequent, hydridation of the IpcRBCl with lithium aluminum hydride (LAH, 0.25 equiv) at -20 or -25 degrees C generated the intermediate isopinocampheylalkylborane (IpcRBH) almost instantly, which then underwent a rapid stereospecific and enantioselective intramolecular cyclic hydroboration to provide the intermediate cyclic trialkylborane. This trialkylborane, on treatment with an aldehyde, liberated the optically pure auxiliary as a-pinene (readily recovered for recycle) to provide the corresponding cyclic borinate ester. This ester reacted smoothly with alpha,alpha-dichloromethyl methyl ether (DCME) in the presence of a hindered base (the DCME reaction) to yield, after oxidation with buffered hydrogen peroxide, the trans-fused bicyclic or cyclic ketone in high enantiomeric excess (ee). In another improved approach, in situ generated IpcBHCl . Et2O, from the reduction of isopinocampheyldichloroborane (IpcBCl(2)) with trimethylsilane (Me3SiH), in the presence of representative dienes in Et2O provided considerably improved optical yields of the bicyclic and cyclic ketones. The trialkylboranes obtained from suitable acyclic dienes can be easily protonolyzed to provide the secondary alcohols in high ee.