ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro<2,5>octane-5-carboxylate | 155853-69-3

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro<2,5>octane-5-carboxylate
• 英文别名: ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro<2.5>octane-5-carboxylate；ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro[2,5]octane-5-carboxylate；ethyl 2,2-dimethoxy-4-methyl-6-oxospiro[7-oxabicyclo[2.2.1]heptane-5,1'-cyclopropane]-1-carboxylate
• CAS: 155853-69-3
• 化学式: C₁₄H₂₀O₆
• 分子量: 284.309
• InChiKey: KMTYUPKZGAZPOB-UHFFFAOYSA-N

物化性质

• 沸点：
  357.0±42.0 °C(predicted)
• 密度：
  1.27±0.1 g/cm3(Temp: 20 °C; Press: 760 Torr)(predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  0.82
• 重原子数：
  20.0
• 可旋转键数：
  4.0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.86
• 拓扑面积：
  71.06
• 氢给体数：
  0.0
• 氢受体数：
  6.0

反应信息

• 作为反应物：
  描述：

  ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro<2,5>octane-5-carboxylate 在 samarium diiodide 作用下， 以 四氢呋喃 为溶剂， 以85%的产率得到ethyl 4-<(methoxycarbonyl)methyl>-4-methyl-7-oxo-5-oxaspiro<2.4>heptane-6-carboxylate
  参考文献：
  名称：

  Synthetic studies toward Illudins and Ptaquilosin. A highly convergent approach via the dipolar cycloaddition of carbonyl ylides

  摘要：

  DOI：

  10.1021/ja00085a076
• 作为产物：
  描述：

  1-乙酰基-环丙烷羧酸 在 rhodium(II) acetate dimer 异丙基溴化镁 、 三乙胺 、 甲烷磺酰基叠氮化物 、 N,N'-羰基二咪唑 作用下， 以 苯 为溶剂， 反应 10.5h， 生成 ethyl 6,6-dimethoxy-5,8-epoxy-8-methyl-4-oxospiro<2,5>octane-5-carboxylate
  参考文献：
  名称：

  Generation and Cycloaddition Behavior of Spirocyclic Carbonyl Ylides. Application to the Synthesis of the Pterosin Family of Sesquiterpenes

  摘要：

  The Rh(II)-catalyzed reaction of 1-acetyl-1-(diazoacetyl)cyclopropane and ethyl 3-(1-acetyl-cyclopropyl)-2-diazo-3-oxopropiolate with various dipolarophiles afforded dipolar cycloadducts in good yield. The reaction involves the formation of a rhodium carbenoid and subsequent transannular cyclization of the electrophilic carbon onto the adjacent keto group to generate a five-membered cyclic carbonyl ylide which undergoes a subsequent dipolar cycloaddition reaction. The regiochemical results encountered can be rationalized on the basis of FMO considerations. For carbonyl ylides, the HOMO dipole is dominant for reactions with electron deficient dipolarophiles, while the LUMO becomes important for cycloaddition to more electron rich species. A short synthesis of several members of the pterosin family of sesquiterpenes is described in which the key step involves a dipolar cycloaddition using a carbonyl ylide. The Rh(II)-catalyzed reaction of 1-acetyl-1-(diazoacetyl)-cyclopropane with cyclopentenone afforded a dipolar cycloadduct in good yield as a 4:1 mixture of diastereomers. Treatment of the major cycloadduct with triphenylphosphonium bromide in the presence of sodium hydride gave the expected Wittig product. The reaction of this compound with acid in the presence of various solvents gave rise to several members of the pterosin family. The overall sequence of reactions can best be described as proceeding by an initial oxy-bridge ring opening followed by dehydration and a subsequent acid-catalyzed cyclopropyl ring opening. The facility of the process is undoubtedly related to the aromaticity gained in the final step.

  DOI：

  10.1021/jo951371e

文献信息

• An Approach toward the Illudin Family of Sesquiterpenes Using the Tandem Cyclization−Cycloaddition Reaction of Rhodium Carbenoids
  作者：Albert Padwa、Erin A. Curtis、Vincent P. Sandanayaka

  DOI：10.1021/jo961574i

  日期：1997.3.1

  The Rh(II)-catalyzed reaction of 1-acetyl-1-(diazoacetyl)cyclopropane with 5,5-dimethylcyclopentenone afforded the product of a 1,3-dipolar cycloaddition in high yield. The reaction involves formation of a rhodium carbenoid and subsequent transannular cyclization of the electrophilic carbon onto the adjacent keto group to generate a five-membered cyclic carbonyl ylide which undergoes a subsequent 1,3-dipolar cycloaddition reaction. The regiochemical results encountered can be rationalized on the basis of FMO considerations. Treatment of the cycloadduct with p-toluene-sulfonic acid results in loss of water followed by a subsequent acid-catalyzed cyclopropyl ketone rearrangement to give dihydrobenzofuran 21. The product distribution derived from the SmI2-induced reduction of the dipolar cycloadduct was found to depend on the reaction conditions. Under kinetic conditions, the reduction resulted in opening of the cyclopropyl ring adjacent to the carbonyl group. However, under thermodynamic conditions, cleavage of the oxy bridge corresponded to the major pathway. The cycloaddition-reduction protocol provides a rapid assembly of the basic core unit of ptaquilosin having most of the functionality in place. Generation of a carbanion adjacent to the oxy bridge leads to opening of the oxabicyclic ring system in a highly regioselective manner. A short synthesis of (+/-)-illudin M and the closely related isodehydroilludin M is described in which the key step involves a dipolar cycloaddition using a carbonyl ylide.