rel-(2S,4R,6R)-2-methoxy-4,5,5,6-tetramethyl-1,3-dioxane | 136764-12-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 氧唑烯
• 英文名称: rel-(2S,4R,6R)-2-methoxy-4,5,5,6-tetramethyl-1,3-dioxane
• CAS: 136764-12-0
• 化学式: C₉H₁₈O₃
• 分子量: 174.24
• InChiKey: JDDCVDFRZGSDHN-BQBZGAKWSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.77
• 重原子数：
  12.0
• 可旋转键数：
  1.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  1.0
• 拓扑面积：
  27.69
• 氢给体数：
  0.0
• 氢受体数：
  3.0

反应信息

• 作为反应物：
  描述：

  rel-(2S,4R,6R)-2-methoxy-4,5,5,6-tetramethyl-1,3-dioxane 在 四氯化钛 作用下， 以 乙醚 、 二氯甲烷 、 甲苯 为溶剂， 反应 1.5h， 生成 rel-(4(R,S),1'R,3'S)-4-(3'-hydroxy-1',2',2'-trimethylbutoxy)-1-decene
  参考文献：
  名称：

  On the stereoselectivity opening of achiral dioxane acetals

  摘要：

  The stereoselectivity of allylation of achiral dioxane acetals cis- and trans-3 and cis- and trans-5 was found to be highly dependent on the nature of the allylmetal reagent, Lewis acid, and stoichiometry. Using TiCl2(O-i-Pr)2 as the Lewis acid in conjunction with allyltrimethylsilane and allyltri-n-butylstannane the selectivity of opening ranged from 1/1 to 18.6/1. In reactions with allyltrimethylsilane, the lack of selectivity for both the cis and trans series (1-2.4/1) was shown to arise from rapid equilibration of ion pairs. Control experiments revealed that the acetals underwent opening faster than isomerization. The reactions with allyltri-n-butylstannane were more selective and dependent on reagent stoichiometry. Moreover, the sense of asymmetric induction for the cis and trans series was opposite. Control experiments again established that isomerization of the acetals occurs slower than reaction with the stannane. These experiments unambiguously rule out the possibility that the opening proceeds via equilibrating ion pairs. The meso dioxane acetal cis-9 reacted with significantly reduced selectivity compared to the 2,4,6-trisubstituted analogue cis-7. On the other hand, the chiral acetal (+/-)-13 reacted much more selectively than the 2,4,6-trisubstituted analogue (+/-)-11. These reactions illustrate the sensitivity of stereochemical outcome to structural and experimental variables and demonstrate the ability to intercept reactive ion pairs under conditions of kinetic control.

  DOI：

  10.1021/jo00022a043
• 作为产物：
  描述：

  (±)-3,3-dimethylpentane-2,4-diol 、 原甲酸三甲酯 在 对甲苯磺酸 作用下， 反应 12.0h， 以43%的产率得到rel-(2S,4R,6R)-2-methoxy-4,5,5,6-tetramethyl-1,3-dioxane
  参考文献：
  名称：

  On the stereoselectivity opening of achiral dioxane acetals

  摘要：

  The stereoselectivity of allylation of achiral dioxane acetals cis- and trans-3 and cis- and trans-5 was found to be highly dependent on the nature of the allylmetal reagent, Lewis acid, and stoichiometry. Using TiCl2(O-i-Pr)2 as the Lewis acid in conjunction with allyltrimethylsilane and allyltri-n-butylstannane the selectivity of opening ranged from 1/1 to 18.6/1. In reactions with allyltrimethylsilane, the lack of selectivity for both the cis and trans series (1-2.4/1) was shown to arise from rapid equilibration of ion pairs. Control experiments revealed that the acetals underwent opening faster than isomerization. The reactions with allyltri-n-butylstannane were more selective and dependent on reagent stoichiometry. Moreover, the sense of asymmetric induction for the cis and trans series was opposite. Control experiments again established that isomerization of the acetals occurs slower than reaction with the stannane. These experiments unambiguously rule out the possibility that the opening proceeds via equilibrating ion pairs. The meso dioxane acetal cis-9 reacted with significantly reduced selectivity compared to the 2,4,6-trisubstituted analogue cis-7. On the other hand, the chiral acetal (+/-)-13 reacted much more selectively than the 2,4,6-trisubstituted analogue (+/-)-11. These reactions illustrate the sensitivity of stereochemical outcome to structural and experimental variables and demonstrate the ability to intercept reactive ion pairs under conditions of kinetic control.

  DOI：

  10.1021/jo00022a043