cis-2-methyl-4-phenyl-1,3-dioxane

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二恶烷
• 英文名称: cis-2-methyl-4-phenyl-1,3-dioxane
• 英文别名: (2S,4S)-2-methyl-4-phenyl-1,3-dioxane
• 化学式: C₁₁H₁₄O₂
• 分子量: 178.231
• InChiKey: QIYXIWADLDVOGM-ONGXEEELSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  13
• 可旋转键数：
  1
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.45
• 拓扑面积：
  18.5
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  乙缩醛 、 1-苯基-1,3-丙二醇 在 对甲苯磺酸 作用下， 以 环己烷 为溶剂， 反应 2.0h， 以70%的产率得到cis-2-methyl-4-phenyl-1,3-dioxane
  参考文献：
  名称：

  Stereochemistry of Carbanions Derived from 1,3-Dioxanes

  摘要：

  Proton abstraction from 4-methyl-1,3-dioxane (1), 2-phenyl-1,3-dioxane (4), 4-phenyl-1,3-dioxane (5), trans-4-methyl-2-phenyl-1,3-dioxane (7), and cis- (12) and trans-2-methyl-4-phenyl-1,3-dioxane (6) by means of BuLi/KO-t-Bu (''Lochmann-Schlosser base'') gave the corresponding carbanions as shown by subsequent deuteronation with EtOD. In contrast, attempted proton abstraction from cis-2-phenyl-4-methyl-1,3-dioxane (3) under the same conditions was unsuccessful, as was abstraction from phenylcyclohexane. Competitive experiments showed that abstraction of the equatorial hydrogen from 7 was about 4 times faster than corresponding abstraction from 6 and that abstraction of the equatorial hydrogen in 6 was well over 25 times faster than abstraction of the axial hydrogen in 12. Deuteronation of the 2-phenyl carbanion from 7 gave the trans isomer 8 in a 70:1 or greater ratio. Deuteronation of the carbanion derived from 6 or 12, in contrast, produced the axial and equatorial 4-phenyl compounds 10 and 11 in a ratio of only about 2:1. The preliminary conclusion that the carbanion derived from 2-phenyl-1,3-dioxane is largely pyramidal, similar to that from 2-phenyl-1,3-dithiane,(8) whereas the 4-phenyl-1,3-dioxanyl carbanion is planar, similar to the phenylcyclohexyl (benzylic) carbanion,(13) was confirmed by C-13 NMR study of these carbanions. The ion derived from 4-phenyl-1,3-dioxane is red and shows the large upfield shifts of the ortho and para ring carbons also seen in the phenylcyclohexyl carbanion(13) and characteristic of planar benzylic carbanions.(12) In contrast, the orange carbanion derived from 2-phenyl-1,3-dioxane (which was very unstable and easily oxidized), to the extent that measurement was possible, showed the smaller upfield para carbon shift characteristic of pyramidal benzylic carbanions.(8b,12) It is concluded that, while two adjacent oxygen atoms mildly stabilize equatorial carbanions (presumably inductively), the destabilizing effect of antiperiplanar lone pairs prevents the 2-phenyl carbanion from becoming planar and inhibits abstraction of the axial hydrogen in compound 3. Reprotonation of the pyramidal ion is stereoselective from the equatorial side. In contrast, in the 4-phenyl carbanion, benzylic resonance stabilization overrides the antiperiplanar effect of one neighboring oxygen atom: Both axial and equatorial hydrogen atoms at C(4) can be abstracted and the carbanion is planar; accordingly reprotonation is essentially nonstereoselective.

  DOI：

  10.1021/ja00143a004

文献信息

• Cation-Exchanged Montmorillonite (M^<i>n</i>+-Mont)-Catalyzed Prins Reaction
  作者：Jun-ichi Tateiwa、Keiji Hashimoto、Takayoshi Yamauchi、Sakae Uemura

  DOI：10.1246/bcsj.69.2361

  日期：1996.8

  The Prins reaction of styrenes with paraformaldehyde or 1,3,5-trioxane in toluene in the presence of cation-exchanged montmorillonite (Mn+-mont), which worked as a Brønsted acid catalyst, at 80 °C produced 4-aryl-1,3-dioxanes selectively in up to 99% isolated yield with a turnover number of up to 5.9 × 102. Among the examined 21 Mn+-monts, Ce3+- and Fe3+-monts were revealed to be quite effective. Regeneration of the catalyst was confirmed with the Ce3+-mont, which could be effectively recycled at least three times. Many lanthanide metal ion-exchanged montmorillonites (Ln3+-monts) were prepared and characterized by X-ray powder diffraction (XRD) and temperature-programmed desorption of ammonia gas (NH3-TPD) methods.

  在甲苯中，使用阳离子交换蒙脱石（Mn+-mont）作为布朗斯台德酸催化剂，在80°C下，苯乙烯与三聚甲醛或1,3,5-三氧六环进行普林斯反应，能够选择性地生成4-芳基-1,3-二氧六环，最高分离收率达99%，转化数高达5.9×102。在考察的21种Mn+-mont中，铈（III）和铁（III）蒙脱石显示出较高的效果。催化剂的再生性通过铈（III）蒙脱石得到证实，它至少可以有效地循环使用三次。许多镧系金属离子交换的蒙脱石（Ln3+-monts）通过X射线粉末衍射（XRD）和程序升温氨气脱附（NH3-TPD）方法制备并表征。