3-methyl-5(E)-(bromomethylidene)tetrahydro-2-furanone | 136408-11-2

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 四氢呋喃
• 英文名称: 3-methyl-5(E)-(bromomethylidene)tetrahydro-2-furanone
• 英文别名: (5E)-5-(bromomethylidene)-3-methyloxolan-2-one
• CAS: 136408-11-2
• 化学式: C₆H₇BrO₂
• 分子量: 191.024
• InChiKey: OFPMKUHVQQKEKE-HWKANZROSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.81
• 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：
  0.5
• 拓扑面积：
  26.3
• 氢给体数：
  0.0
• 氢受体数：
  2.0

反应信息

• 作为产物：
  描述：

  2-甲基戊-4-炔酸 在 N-溴代丁二酰亚胺(NBS) 、 水 、 potassium hydrogencarbonate 作用下， 生成 3-methyl-5(E)-(bromomethylidene)tetrahydro-2-furanone
  参考文献：
  名称：

  Stereoselective Z- and E-bromoenol lactonization of alkynoic acids

  摘要：

  We have found that treatment of the silver salt of a 4- or 5-terminal alkynoic acid with bromine results in clean formation of the corresponding Z-bromo enol lactone, the result of a formal cis addition of carboxylate and bromine across the triple bond. This Z-bromo enol lactonization is highly stereoselective and gives good yields in systems that bear substituents on the internal methylene groups; yields with unsubstituted or terminally substituted alkynoic acids are modest. The E-bromo enol lactonization reaction, reported by us previously (Krafft, G. A.; Katzenellenbogen, J. A. J. Am. Chem. Soc. 1981, 103, 5459), has a broader scope and, with modifications, can be performed with high reliability. Mercury(II) salts equilibrate the Z- and E-bromo enol lactones, presumedly by a mercuric ion addition-elimination mechanism. These three reactions provide access to an array of stereoisomeric bromo enol lactone systems.

  DOI：

  10.1021/jo00024a035

文献信息

• Stereoselective Z- and E-bromoenol lactonization of alkynoic acids
  作者：Wei Dai、John A. Katzenellenbogen

  DOI：10.1021/jo00024a035

  日期：1991.11

  We have found that treatment of the silver salt of a 4- or 5-terminal alkynoic acid with bromine results in clean formation of the corresponding Z-bromo enol lactone, the result of a formal cis addition of carboxylate and bromine across the triple bond. This Z-bromo enol lactonization is highly stereoselective and gives good yields in systems that bear substituents on the internal methylene groups; yields with unsubstituted or terminally substituted alkynoic acids are modest. The E-bromo enol lactonization reaction, reported by us previously (Krafft, G. A.; Katzenellenbogen, J. A. J. Am. Chem. Soc. 1981, 103, 5459), has a broader scope and, with modifications, can be performed with high reliability. Mercury(II) salts equilibrate the Z- and E-bromo enol lactones, presumedly by a mercuric ion addition-elimination mechanism. These three reactions provide access to an array of stereoisomeric bromo enol lactone systems.