(E)-5-Ethylidene-2,3-dimethyl-2-cyclopentenone | 42507-31-3

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: (E)-5-Ethylidene-2,3-dimethyl-2-cyclopentenone
• 英文别名: 5-ethylidene-2,3-dimethylcyclopent-2-enone；(5E)-5-ethylidene-2,3-dimethylcyclopent-2-en-1-one
• CAS: 42507-31-3
• 化学式: C₉H₁₂O
• 分子量: 136.194
• InChiKey: UQLVDFHNVGMICI-XBXARRHUSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.7
• 重原子数：
  10
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.44
• 拓扑面积：
  17.1
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  2,3-二甲基丁-2-烯醛 在 manganese(IV) oxide 、 正丁基锂 、 三苯基甲烷 、 1,2-环氧辛烷 、 天然维生素E 作用下， 以 四氢呋喃 、 正己烷 、 二氯甲烷 为溶剂， 反应 36.25h， 生成 (E)-5-Ethylidene-2,3-dimethyl-2-cyclopentenone
  参考文献：
  名称：

  Enynones in Organic Synthesis. 7. Substituent Effects on the .alpha.-Tocopherol-Catalyzed Cyclization of Enynones to Methylenecyclopentenones. Convenient Syntheses of Members of the Methylenomycin Class of Antibiotics

  摘要：

  Substituent effects on the a-tocopherol (vitamin E, 3b) catalyzed cyclization of a wide variety of enynones 1a-z to methylenecyclopentenones 7a-z have been examined, with particular emphasis given to electron-withdrawing and -donating groups at positions 2-4 and 6. In general, electron-withdrawing groups at positions 4 and 6 dramatically accelerate the cyclization process, while strong electron-donating groups at positions 3 and 4 completely inhibit reaction. Relatively little effect is exerted by groups at C-2, except for the methyl ester derivative 1i, which is totally unreactive. This methodology was employed in the syntheses of the methylenecyclopentenone antibiotics methylenomycin B (7a) and desepoxy-4,5-didehydromethylenomycin A (7z) and in formal syntheses of methylenomycin A (8) and xanthocidin (9).

  DOI：

  10.1021/jo00097a036

文献信息

• Convergent synthesis of methylenomycin B via selenium-assisted intramolecular S N 2? cyclization
  作者：Jacob Mathew

  DOI：10.1039/c39900001264

  日期：——

  A highly convergent and efficient synthesis of methylenomycin B has been achieved by the reaction of the lithium enolate of 4-chloro-4,5-dimethyl-5-hexen-3-one with phenylselenenyl bromide followed by selenoxide elimination.

  通过使4-氯-4,5-二甲基-5-己烯-3-酮的烯醇锂与苯基硒烯基溴化物反应，然后除去亚硒酸酯，可以实现高度收敛和高效合成甲基霉素B的合成。
• Mathew, Jacob, Journal of the Chemical Society. Perkin transactions I, 1991, # 8, p. 2039 - 2043
  作者：Mathew, Jacob

  DOI：——

  日期：——
• MATHEW, JACOB, J. CHEM. SOC. CHEM. COMMUN.,(1990) N8, C. 1264-1266
  作者：MATHEW, JACOB

  DOI：——

  日期：——
• Enynones in Organic Synthesis. 7. Substituent Effects on the .alpha.-Tocopherol-Catalyzed Cyclization of Enynones to Methylenecyclopentenones. Convenient Syntheses of Members of the Methylenomycin Class of Antibiotics
  作者：Peter A. Jacobi、Harry L. Brielmann、Reginald O. Cann

  DOI：10.1021/jo00097a036

  日期：1994.9

  Substituent effects on the a-tocopherol (vitamin E, 3b) catalyzed cyclization of a wide variety of enynones 1a-z to methylenecyclopentenones 7a-z have been examined, with particular emphasis given to electron-withdrawing and -donating groups at positions 2-4 and 6. In general, electron-withdrawing groups at positions 4 and 6 dramatically accelerate the cyclization process, while strong electron-donating groups at positions 3 and 4 completely inhibit reaction. Relatively little effect is exerted by groups at C-2, except for the methyl ester derivative 1i, which is totally unreactive. This methodology was employed in the syntheses of the methylenecyclopentenone antibiotics methylenomycin B (7a) and desepoxy-4,5-didehydromethylenomycin A (7z) and in formal syntheses of methylenomycin A (8) and xanthocidin (9).