(E)-5-Ethylidene-3-methyl-2-cyclopenten-1-one | 120696-32-4

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: (E)-5-Ethylidene-3-methyl-2-cyclopenten-1-one
• 英文别名: 5-ethylidene-3-methylcyclopent-2-en-1-one
• CAS: 120696-32-4；120696-37-9
• 化学式: C₈H₁₀O
• 分子量: 122.167
• InChiKey: VJUBXTOKUUPBDR-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.85
• 重原子数：
  9.0
• 可旋转键数：
  0.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.38
• 拓扑面积：
  17.07
• 氢给体数：
  0.0
• 氢受体数：
  1.0

反应信息

• 作为产物：
  描述：

  3-甲基巴豆酰氯 在 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 various solvent(s) 为溶剂， 反应 51.25h， 生成 (E)-5-Ethylidene-3-methyl-2-cyclopenten-1-one
  参考文献：
  名称：

  Enynones in Organic Synthesis. 6. Synthesis of Spirocyclic Methylenecyclopentenones and Analogs of the Methylenomycin Class of Antibiotics. Mechanism of Phenol Catalysis

  摘要：

  Spirocyclic methylenecyclopentenones of general structure 18 were prepared in a single step from bis-acetylenic alcohols 29 by a process involving initial oxy-Cope rearrangement to afford (Z)-enynones 30-Z followed by electrocyclic ring closure. Mechanistic studies indicate that the initial step leading from 30-Z to 18 is a thermal 1,5-prototropic shift to afford dienols which can cyclize by a symmetry-allowed (pi(4)s + sigma(2)s + pi(2)a) process. This last step is catalyzed by certain phenols having low oxidation potentials, most likely by a mechanism involving single electron transfer. Dramatic rate enhancements were also observed for the cyclization of simple enynones 37 to methylenecyclopentenones 39 upon catalysis with either a-tocopherol (vitamin E, 40) or tert-butylcatechol(41). Further enhancements in both rate and yield were obtained under conditions of photoassisted single electron transfer (PET), which afforded 39 in yields of 80-98%.

  DOI：

  10.1021/jo00097a035

文献信息

• Enynones in Organic Synthesis. 8. Synthesis of the Antimicrobial-Cytotoxic Agent Juncusol and Members of the Effusol Class of Phenols
  作者：Peter A. Jacobi、Joseph I. Kravitz、Wanjun Zheng

  DOI：10.1021/jo00107a017

  日期：1995.1

  Two new syntheses of phenols have been developed which have been utilized in an efficient preparation of the antimicrobial-cytotoxic agent juncusol (22) and several members of the effusol (23) class of phenols. These results complement our earlier studies with enynones of type 42 and provide for the highly efficient conversion of 42 to either methylenecyclopentenones 45 or phenols of type 47 or 54 with virtually 100% selectivity.
• Enynones in organic synthesis. II. An electron transfer mediated synthesis of methylenecyclopentenones
  作者：Peter A Jacobi、Lisa M Armacost、Joseph I Kravitz、Michael J Martinelli

  DOI：10.1016/s0040-4039(00)88462-2

  日期：1988.1