3,7-dimethyl-1H-indene-2-carboxylic acid methyl ester | 197851-07-3

• 分子结构分类: 有机化合物 - 苯类化合物 - 茚和异茚
• 英文名称: 3,7-dimethyl-1H-indene-2-carboxylic acid methyl ester
• 英文别名: methyl 3,7-dimethyl-1H-indene-2-carboxylate
• CAS: 197851-07-3
• 化学式: C₁₃H₁₄O₂
• 分子量: 202.253
• InChiKey: TWLPDWPUDQITLZ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.6
• 重原子数：
  15
• 可旋转键数：
  2
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.31
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  2-(2-methylbenzyl)-3-oxo-butyric acid methyl ester 在 三氟甲磺酸 作用下， 以 二氯甲烷 为溶剂， 以66%的产率得到3,7-dimethyl-1H-indene-2-carboxylic acid methyl ester
  参考文献：
  名称：

  Cyclization of Arylacetoacetates to Indene and Dihydronaphthalene Derivatives in Strong Acids. Evidence for Involvement of Further Protonation of O,O-Diprotonated β-Ketoester, Leading to Enhancement of Cyclization

  摘要：

  The chemical features, such as substrate stability, product distribution, and substrate generality, and the reaction mechanism of Bronsted superacid-catalyzed cyclization reactions of aromatic ring-containing acetoacetates (beta-ketoesters) were examined in detail. While two types of carbonyl cyclization are possible, i.e., keto cyclization and ester cyclization, the former was found to take place exclusively. The reaction constitutes an efficient method to synthesize indene and 3,4-dihydronapthalene derivatives. Acid-base titration monitored with C-13 NMR spectroscopy showed that the acetoacetates are fully O-1,O-3-diprotonated at H-0 = -11. While the five-membered ring cyclization of the arylacetoacetates proceeded slowly at H-0 = -11, a linear increase in the rate of the cyclization was found with increasing acidity in the high acidity region of H-0 = -11.8 to -13.3. Therefore, the O-1,O-3-diprotonated acetoacetates exhibited some cyclizing reactivity, but they are not the reactive intermediates responsible for the acceleration of the cyclization in the high acidity region. The reactive cationic species might be formed by further protonation (or protosolvation) of the O-1,O-3-diprotonated acetoacetates; i.e., they may be tricationic species. Thermochemical data on the acid-catalyzed cyclization of the arylacetoacetates showed that the activation energy is decreased significantly as compared with that of the related acid-catalyzed cyclization reaction of a compound bearing a single functional group, such as a ketone. These findings indicate that intervention of the trication contributes to the activation of the cyclization of arylacetoacetates in strong acid, and the electron-withdrawing nature of the O-protonated ester functionality significantly increases the electrophilicity of the ketone moiety.

  DOI：

  10.1021/ja908749u

文献信息

• Cyclization of Arylacetoacetates to Indene and Dihydronaphthalene Derivatives in Strong Acids. Evidence for Involvement of Further Protonation of O,O-Diprotonated β-Ketoester, Leading to Enhancement of Cyclization
  作者：Hiroaki Kurouchi、Hiromichi Sugimoto、Yuko Otani、Tomohiko Ohwada

  DOI：10.1021/ja908749u

  日期：2010.1.20

  The chemical features, such as substrate stability, product distribution, and substrate generality, and the reaction mechanism of Bronsted superacid-catalyzed cyclization reactions of aromatic ring-containing acetoacetates (beta-ketoesters) were examined in detail. While two types of carbonyl cyclization are possible, i.e., keto cyclization and ester cyclization, the former was found to take place exclusively. The reaction constitutes an efficient method to synthesize indene and 3,4-dihydronapthalene derivatives. Acid-base titration monitored with C-13 NMR spectroscopy showed that the acetoacetates are fully O-1,O-3-diprotonated at H-0 = -11. While the five-membered ring cyclization of the arylacetoacetates proceeded slowly at H-0 = -11, a linear increase in the rate of the cyclization was found with increasing acidity in the high acidity region of H-0 = -11.8 to -13.3. Therefore, the O-1,O-3-diprotonated acetoacetates exhibited some cyclizing reactivity, but they are not the reactive intermediates responsible for the acceleration of the cyclization in the high acidity region. The reactive cationic species might be formed by further protonation (or protosolvation) of the O-1,O-3-diprotonated acetoacetates; i.e., they may be tricationic species. Thermochemical data on the acid-catalyzed cyclization of the arylacetoacetates showed that the activation energy is decreased significantly as compared with that of the related acid-catalyzed cyclization reaction of a compound bearing a single functional group, such as a ketone. These findings indicate that intervention of the trication contributes to the activation of the cyclization of arylacetoacetates in strong acid, and the electron-withdrawing nature of the O-protonated ester functionality significantly increases the electrophilicity of the ketone moiety.