3-Methyl-5,7-dichloro-2,3-dihydrobenzofuran

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 香豆素
• 英文名称: 3-Methyl-5,7-dichloro-2,3-dihydrobenzofuran
• 英文别名: 5,7-Dichloro-3-methyl-2,3-dihydro-1-benzofuran
• 化学式: C₉H₈Cl₂O
• 分子量: 203.068
• InChiKey: SAPGXNWPCXPGPP-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.5
• 重原子数：
  12
• 可旋转键数：
  0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.33
• 拓扑面积：
  9.2
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  sodium 2,4,6-trichlorophenolate 在 samarium diiodide 作用下， 以 四氢呋喃 、 六甲基磷酰三胺 为溶剂， 反应 6.0h， 生成 3-Methyl-5,7-dichloro-2,3-dihydrobenzofuran
  参考文献：
  名称：

  Cyclizations and Rearrangements of Samarium Diiodide-Generated Vinyl Radicals

  摘要：

  Vinyl bromides 1, 5, 15, 20, 23, 27, 33a,b, 41a-c, 44a-c, 46a,b, 52a,b, 55a, 56a,b, and 60a,b react with samarium diiodide in THF and/or acetonitrile to give the corresponding vinyl radicals. Radicals 3, 7, and 16 afforded products deriving from cyclization on the adjacent triple bond in a 5-(pi-exo)exo, 6-(pi-endo)exo, and 6-(pi-exo)exo mode, respectively. Radical 7 undergoes competitive 1,5-hydrogen translocation. Vinyl radicals 21 and 24 readily cyclize on the proximal double bond, leading to 5- and 6-membered rings, respectively. Thienyl-substituted radical 28 leads to a product deriving from 5-exo cyclization on the thiophene ring and subsequent beta-fission of the C-S bond, whereas thienyl-substituted radicals 34a,b undergo almost exclusively 1,5-hydrogen translocation. Aryl-substituted radicals obtained from vinyl bromides 41, 44, 46, 52, and 55 do not form any products deriving from 5-exo or 6-exo cyclization (or ipso cyclization). Finally, naphthyl-substituted radicals 57a and 61a give only direct reduction products, whereas the radical 61b affords, in addition to the direct reduction product, a rearranged product deriving from a 1,3-radical migration of the naphthylthio group. Evidence is reported for the reduction of EWG-substituted benzene rings and thio-substituted naphthalene rings to radical anions, which can fragment on the side chain with the elimination of allyl radicals. alpha-Oxy(and alpha-thio)-substituted radicals deriving from 1,5-shift rearrange to alcohols (and thiols) through a Wittig rearrangement or a cyclization/fragmentation process.

  DOI：

  10.1021/jo00128a013

文献信息

• Cyclizations and Rearrangements of Samarium Diiodide-Generated Vinyl Radicals
  作者：Laura Capella、Pier Carlo Montevecchi、Maria Luisa Navacchia

  DOI：10.1021/jo00128a013

  日期：1995.11

  Vinyl bromides 1, 5, 15, 20, 23, 27, 33a,b, 41a-c, 44a-c, 46a,b, 52a,b, 55a, 56a,b, and 60a,b react with samarium diiodide in THF and/or acetonitrile to give the corresponding vinyl radicals. Radicals 3, 7, and 16 afforded products deriving from cyclization on the adjacent triple bond in a 5-(pi-exo)exo, 6-(pi-endo)exo, and 6-(pi-exo)exo mode, respectively. Radical 7 undergoes competitive 1,5-hydrogen translocation. Vinyl radicals 21 and 24 readily cyclize on the proximal double bond, leading to 5- and 6-membered rings, respectively. Thienyl-substituted radical 28 leads to a product deriving from 5-exo cyclization on the thiophene ring and subsequent beta-fission of the C-S bond, whereas thienyl-substituted radicals 34a,b undergo almost exclusively 1,5-hydrogen translocation. Aryl-substituted radicals obtained from vinyl bromides 41, 44, 46, 52, and 55 do not form any products deriving from 5-exo or 6-exo cyclization (or ipso cyclization). Finally, naphthyl-substituted radicals 57a and 61a give only direct reduction products, whereas the radical 61b affords, in addition to the direct reduction product, a rearranged product deriving from a 1,3-radical migration of the naphthylthio group. Evidence is reported for the reduction of EWG-substituted benzene rings and thio-substituted naphthalene rings to radical anions, which can fragment on the side chain with the elimination of allyl radicals. alpha-Oxy(and alpha-thio)-substituted radicals deriving from 1,5-shift rearrange to alcohols (and thiols) through a Wittig rearrangement or a cyclization/fragmentation process.