5-Methylcyclopenten-2-one ethylene acetal | 150313-16-9

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 5-Methylcyclopenten-2-one ethylene acetal
• 英文别名: 9-methyl-1,4-dioxaspiro[4.4]non-6-ene
• CAS: 150313-16-9
• 化学式: C₈H₁₂O₂
• 分子量: 140.182
• InChiKey: ALFOEMAQBHGBGD-UHFFFAOYSA-N

物化性质

• 沸点：
  193.4±35.0 °C(Predicted)
• 密度：
  1.07±0.1 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  1.33
• 重原子数：
  10.0
• 可旋转键数：
  0.0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.75
• 拓扑面积：
  18.46
• 氢给体数：
  0.0
• 氢受体数：
  2.0

反应信息

• 作为反应物：
  描述：

  5-Methylcyclopenten-2-one ethylene acetal 在 2,6-二甲基吡啶 、 氢氧化钾 作用下， 以 二甲基亚砜 、 乙腈 为溶剂， 反应 126.0h， 生成
  参考文献：
  名称：

  A one-step synthesis of 2-norbornanone ethylene acetals from 2-cyclopenten-1-one ethylene acetals and dienophiles via [2 + 4] cycloaddition of in situ generated 2-(2-hydroxyethoxy)cyclopenta-1,3-dienes and intramolecular reacetalization

  摘要：

  2-(2-Hydroxyethoxy)cyclopenta-1,3-diene (5) which is generated reversibly from 2-cyclopenten-1-one ethylene acetal (1) under mild, neutral conditions can be intercepted with a variety of dienophiles ultimately to give 2-norbornanone ethylene acetals in 62-100% yields. The addition reactions are highly stereo- and regioselective. Of the several solvents examined, acetonitrile is the most satisfactory. In CHCl3 or CCl4, decomposition of 1 is induced, leading to diminished yields of the adducts. The intermediate 5 is detected by UV spectroscopy, and its content relative to 1 at a stationary state at 70-degrees-C in acetonitrile is estimated to be ca. 0.2%. The reactions of the 2-, 3-, and 5-methyl-substituted derivatives 2-4 with dienophiles similarly led to the production of the corresponding 2-norbornanone acetals through the additions of the dienophiles to the 1,3-cyclopentadien-2-yl ether intermediates 6-8 selectively derived from 2-4 via 1,2-elimination. The formation of isomeric adducts resulting either from 1,4-elimination in 1-4 or from [1,51 hydrogen migration in the enol ether intermediates is not detected. The addition of 2-chloroacrylonitrile, a ketene equivalent, to 1-4 followed by alkaline hydrolysis provides singly acetalized 2,5-norbornadiones in two steps in good yields. 2-Cyclohexen-1-one ethylene acetal (44) also undergoes the addition of dienophiles in the [2 + 4] manner directly to give bicyclo[2.2.2]octan-2-one ethylene acetals, but is substantially less reactive than 1 toward this type of reaction.

  DOI：

  10.1021/jo00071a033
• 作为产物：
  描述：

  5-甲基环戊-2-烯-1-酮 、 乙二醇 在 1-Hydroxy-3-(isothiocyanato)-tetrabutyldistannoxane 作用下， 以 苯 为溶剂， 反应 48.0h， 以27%的产率得到5-Methylcyclopenten-2-one ethylene acetal
  参考文献：
  名称：

  A one-step synthesis of 2-norbornanone ethylene acetals from 2-cyclopenten-1-one ethylene acetals and dienophiles via [2 + 4] cycloaddition of in situ generated 2-(2-hydroxyethoxy)cyclopenta-1,3-dienes and intramolecular reacetalization

  摘要：

  2-(2-Hydroxyethoxy)cyclopenta-1,3-diene (5) which is generated reversibly from 2-cyclopenten-1-one ethylene acetal (1) under mild, neutral conditions can be intercepted with a variety of dienophiles ultimately to give 2-norbornanone ethylene acetals in 62-100% yields. The addition reactions are highly stereo- and regioselective. Of the several solvents examined, acetonitrile is the most satisfactory. In CHCl3 or CCl4, decomposition of 1 is induced, leading to diminished yields of the adducts. The intermediate 5 is detected by UV spectroscopy, and its content relative to 1 at a stationary state at 70-degrees-C in acetonitrile is estimated to be ca. 0.2%. The reactions of the 2-, 3-, and 5-methyl-substituted derivatives 2-4 with dienophiles similarly led to the production of the corresponding 2-norbornanone acetals through the additions of the dienophiles to the 1,3-cyclopentadien-2-yl ether intermediates 6-8 selectively derived from 2-4 via 1,2-elimination. The formation of isomeric adducts resulting either from 1,4-elimination in 1-4 or from [1,51 hydrogen migration in the enol ether intermediates is not detected. The addition of 2-chloroacrylonitrile, a ketene equivalent, to 1-4 followed by alkaline hydrolysis provides singly acetalized 2,5-norbornadiones in two steps in good yields. 2-Cyclohexen-1-one ethylene acetal (44) also undergoes the addition of dienophiles in the [2 + 4] manner directly to give bicyclo[2.2.2]octan-2-one ethylene acetals, but is substantially less reactive than 1 toward this type of reaction.

  DOI：

  10.1021/jo00071a033

文献信息

• A one-step synthesis of 2-norbornanone ethylene acetals from 2-cyclopenten-1-one ethylene acetals and dienophiles via [2 + 4] cycloaddition of in situ generated 2-(2-hydroxyethoxy)cyclopenta-1,3-dienes and intramolecular reacetalization
  作者：Masakazu Ohkita、Osamu Nishizawa、Takashi Tsuji、Shinya Nishida

  DOI：10.1021/jo00071a033

  日期：1993.9

  2-(2-Hydroxyethoxy)cyclopenta-1,3-diene (5) which is generated reversibly from 2-cyclopenten-1-one ethylene acetal (1) under mild, neutral conditions can be intercepted with a variety of dienophiles ultimately to give 2-norbornanone ethylene acetals in 62-100% yields. The addition reactions are highly stereo- and regioselective. Of the several solvents examined, acetonitrile is the most satisfactory. In CHCl3 or CCl4, decomposition of 1 is induced, leading to diminished yields of the adducts. The intermediate 5 is detected by UV spectroscopy, and its content relative to 1 at a stationary state at 70-degrees-C in acetonitrile is estimated to be ca. 0.2%. The reactions of the 2-, 3-, and 5-methyl-substituted derivatives 2-4 with dienophiles similarly led to the production of the corresponding 2-norbornanone acetals through the additions of the dienophiles to the 1,3-cyclopentadien-2-yl ether intermediates 6-8 selectively derived from 2-4 via 1,2-elimination. The formation of isomeric adducts resulting either from 1,4-elimination in 1-4 or from [1,51 hydrogen migration in the enol ether intermediates is not detected. The addition of 2-chloroacrylonitrile, a ketene equivalent, to 1-4 followed by alkaline hydrolysis provides singly acetalized 2,5-norbornadiones in two steps in good yields. 2-Cyclohexen-1-one ethylene acetal (44) also undergoes the addition of dienophiles in the [2 + 4] manner directly to give bicyclo[2.2.2]octan-2-one ethylene acetals, but is substantially less reactive than 1 toward this type of reaction.