(+/-)-Obtusafuran | 21008-39-9

• 分子结构分类: 有机化合物 - 苯丙烷和聚酮 - 2-芳基苯并呋喃类黄酮
• 英文名称: (+/-)-Obtusafuran
• 英文别名: (2S)-2alpha-Phenyl-3beta-methyl-6-methoxy-2,3-dihydrobenzofuran-5-ol；(2S,3S)-6-methoxy-3-methyl-2-phenyl-2,3-dihydro-1-benzofuran-5-ol
• CAS: 21008-39-9；21008-40-2；37674-33-2；117471-20-2
• 化学式: C₁₆H₁₆O₃
• 分子量: 256.301
• InChiKey: FRERFZXINXYHDY-QFYYESIMSA-N

物化性质

• 熔点：
  110-113 °C
• 沸点：
  378.0±42.0 °C(Predicted)
• 密度：
  1.185±0.06 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  3.4
• 重原子数：
  19
• 可旋转键数：
  2
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  38.7
• 氢给体数：
  1
• 氢受体数：
  3

安全信息

• 海关编码：
  2932999099

反应信息

• 作为产物：
  描述：

  甲氧苯醌 在 硫酸 、 四氯化钛 作用下， 以 二氯甲烷 为溶剂， 反应 1.33h， 生成 (+/-)-Obtusafuran
  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

• Stereoselective 3 + 2 and stereospecific 2 + 2 cycloaddition reactions of alkenes and quinones
  作者：Thomas A. Engler、Keith D. Combrink、James E. Ray

  DOI：10.1021/ja00231a084

  日期：1988.11

  mM NaCl and 25 mM tris-acetate at pH 7.0.14 After 0.5 h incubation at 24 OC, 4 mM dithiothreitol was added to initiate strand cleavage. The reaction was allowed to continue for 6 h (24 "C). The double strand cleavage products were separated on a 0.4% vertical agarose gel which resolves DNA segments up to 25 kbp in size (Figure 3). Therefore, DNA uniquely labeled at the R and

  pH 7.0.14 的 mM NaCl 和 25 mM tris-乙酸盐 在 24 ℃下孵育 0.5 小时后，加入 4 mM 二硫苏糖醇以启动链裂解。使反应持续 6 小时（24°C）。双链切割产物在 0.4% 垂直琼脂糖凝胶上分离，该凝胶可解析大小高达 25 kbp 的 DNA 片段（图 3）。因此，DNA 在R 和
• 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