rac-(4bR,5R,9S,9aS)-4b,5,7,8,9,9a-hexamethyl-6,11-dimethylene-4b,5,6,9,9a,10-hexahydro-5,9-methanobenzo[a]azulene | 126402-12-8

• 分子结构分类: 有机化合物 - 苯类化合物 - 茚满类
• 英文名称: rac-(4bR,5R,9S,9aS)-4b,5,7,8,9,9a-hexamethyl-6,11-dimethylene-4b,5,6,9,9a,10-hexahydro-5,9-methanobenzo[a]azulene
• CAS: 126402-12-8
• 化学式: C₁₆H₁₄O₃
• 分子量: 254.285
• InChiKey: VIMRSCGIHINOOI-RNJOBUHISA-N

物化性质

• 沸点：
  487.3±45.0 °C(Predicted)
• 密度：
  1.365±0.06 g/cm3(Temp: 20 °C; Press: 760 Torr)(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  2.17
• 重原子数：
  19.0
• 可旋转键数：
  0.0
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.38
• 拓扑面积：
  54.37
• 氢给体数：
  1.0
• 氢受体数：
  3.0

反应信息

• 作为产物：
  描述：

  2-((4-methoxybenzyl)oxy)-6-methyl-1,4-benzoquinone 、 茚 在 titanium(IV) isopropylate 、 四氯化钛 作用下， 以 二氯甲烷 为溶剂， 以63%的产率得到rac-(4bR,5R,9S,9aS)-4b,5,7,8,9,9a-hexamethyl-6,11-dimethylene-4b,5,6,9,9a,10-hexahydro-5,9-methanobenzo[a]azulene
  参考文献：
  名称：

  Stereospecific Lewis Acid-Promoted Reactions of Styrenyl Systems with 2-Alkoxy-(6-Alkyl)-1,4-Benzoquinones: Scope, Limitations, and Synthetic Applications

  摘要：

  Titanium(IV)-promoted reactions of various (E)-1-propenylbenzenes with 2-methoxy- and 2-methoxy-6-methyl-1,4-benzoquinones produce trans 2-aryl-6-methoxy-3-(and 4-di)methyl-2,3-dihydro-5-benzofuranols (10-12), rel-(1S,6R,7R,8R)-3-methoxy-8-aryl-7-(and 1-di)methylbicyclo[4.2.0]oct-3-ene-2,5-diones (2 + 2 cycloadducts, 13-15) and/or rel-(1R,5R,6R,7R)-7-aryl-3-hydroxy-6-(and 4)methylbicyclo[3.2.1]oct-3-ene-2,8-diones (5 + 2 cycloadducts, 16/17). In many cases, each of the three products can be obtained selectively in good yield by control of reaction conditions and/or by choice of substituents on the quinone or the propenylbenzene. The dihydrobenzofurans are formed stereoselectively, whereas the formation of the bicyclo[4.2.0] systems are stereospecific processes. Thus, reactions of (Z)-1-propenylbenzenes afford rel-(1R,6S,7R,8R)-8-aryl-3-methoxy-7-methylbicyclo[4.2.0]oct-3-ene-2,5-diones (24, 25). No bicyclo[3.2.1]systems. are found in reactions of the (Z)-propenylbenzenes. The products all apparently result from a thermally allowed 2 pi + 4 pi (2 + 5) cycloaddition of the propenylbenzene with a 2-methoxy-4-oxo-2,5-cyclohexadienyl carbocation intermediate (26) formed by coordination of the Ti(IV) to the C-1 carbonyl oxygen of the quinone. In the cycloaddition, the aryl ring of the propenylbenzene occupies an endo position with respect to the pentadienyl carbocation moiety of 26 and the bicyclo[3.2.1] carbocation product of the cycloaddition (28/29) either undergoes dealkylation or rearrangment to yield the observed products. Treatment of the bicylo[4.2.0] systems with protic acid effects their rearrangement to the dihydrobenzofuranols. Reactions of 2-propenylbenzenes and arylcycloalkenes with the quinones regioselectively give dihydrobenzofuranols 43-45 and 49-54, respectively; a 2 + 2 cycloadduct is found in low yield in only one case. The 7-aryl-3-hydroxy-6-methylbicyclo[3.2.1]oct-3-ene-2,8-diones are produced exclusively in reactions of 2-((4-methoxybenzyl)oxy)-1,4-benzoquinones with various propenylbenzenes. Application of these reactions to the synthesis of (+/-)-obtusafuran, (+/-)-liliflol-B, (+/-)-kadsurenone, and (+/-) denudatin are reported.

  DOI：

  10.1021/jo00101a016

文献信息

• Isolation of bicyclo[3.2.1]oct-3-ene-2,8-dione products (formal 5 + 2 cycloadducts) from reactions of styrenes with 2-alkoxy-1,4-benzoquinones
  作者：Thomas A. Engler、Keith D. Combrink、Fusao Takusagawa

  DOI：10.1039/c39890001573

  日期：——

  Titanium(IV) catalysed reactions of 2-alkoxy-1,4-benzoquinones and various trans-β-methylstyrenes stereoselectivity produce 7-aryl-3-hydroxy-6-methylbicyclo[3.2.1]oct-3-ene-2,8-diones in moderate yield.

  钛（IV）催化2-烷氧基-1,4-苯醌和各种反式-β-甲基苯乙烯的立体选择性，生成7-芳基-3-羟基-6-甲基双环[3.2.1] oct-3-ene-2,8 -二酮产量中等。
• Selective control of the various cycloaddition products from reactions of styrenes and 1,4-benzoquinones: optimization of the formal 5 + 2 cycloadducts
  作者：Thomas A. Engler、Michael A. Letavic、Keith D. Combrink、Fusao Takusagawa

  DOI：10.1021/jo00310a005

  日期：1990.11