1a,7a-Dimethyloxireno[2,3-b][1,4]benzodioxine | 134434-20-1

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二恶英
• 英文名称: 1a,7a-Dimethyloxireno[2,3-b][1,4]benzodioxine
• CAS: 134434-20-1
• 化学式: C₁₀H₁₀O₃
• 分子量: 178.188
• InChiKey: MEOVELWSJGSGLC-UHFFFAOYSA-N

物化性质

• 沸点：
  238.0±39.0 °C(Predicted)
• 密度：
  1.294±0.06 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  2
• 重原子数：
  13
• 可旋转键数：
  0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.4
• 拓扑面积：
  31
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  1a,7a-Dimethyloxireno[2,3-b][1,4]benzodioxine 以 丙酮 为溶剂， 反应 12.0h， 生成 2-Acetyl-2-methyl-1,3-benzodioxolane
  参考文献：
  名称：

  Dimethyldioxirane epoxidation of alkenes bearing two electron donating substituents.

  摘要：

  Various enol-type alkenes, such as 2,3-dimethylbenzodioxin (1), O-tetrabenzyl glycal (3), 1,2-bis(trimethylsilyloxy)cycloalkenes (9) were transformed in excellent yields to their labile epoxides by dimethyldioxirane (as acetone solution); the silyl ketene acetal 5 and 2-methyl-3-trimethylsilyloxybenzo[b]furan (7) gave the corresponding epoxide rearrangement products.

  DOI：

  10.1016/s0040-4039(00)79649-3
• 作为产物：
  描述：

  2,3-Dimethyl-1,4-benzodioxin 在 二甲基二环氧乙烷 作用下， 以 二氯甲烷 、 丙酮 为溶剂， 反应 0.5h， 以100%的产率得到1a,7a-Dimethyloxireno[2,3-b][1,4]benzodioxine
  参考文献：
  名称：

  Dimethyldioxirane epoxidation of alkenes bearing two electron donating substituents.

  摘要：

  Various enol-type alkenes, such as 2,3-dimethylbenzodioxin (1), O-tetrabenzyl glycal (3), 1,2-bis(trimethylsilyloxy)cycloalkenes (9) were transformed in excellent yields to their labile epoxides by dimethyldioxirane (as acetone solution); the silyl ketene acetal 5 and 2-methyl-3-trimethylsilyloxybenzo[b]furan (7) gave the corresponding epoxide rearrangement products.

  DOI：

  10.1016/s0040-4039(00)79649-3

文献信息

• Stereoselective Cycloaddition and Epoxidation of Enol Ethers by α-Peroxy Lactone as a Function of Steric and Stereoelectronic Effects
  作者：Waldemar Adam、Lluís Blancafort

  DOI：10.1021/jo961645d

  日期：1996.1.1

  The reaction of mono- and dioxy-substituted olefins 2 with dimethyl alpha-peroxy lactone 1 affords the cycloaddition products 3 and the epoxides 4 with a high degree of stereoretention of the initial olefin configuration. Only for the pyran 2c is the ene product 5c obtained. When the reaction is run in methanol as cosolvent, additionally the trapping products 6 are observed. The S(N)2 reaction is found to be highly regioselective in all cases, as displayed by the cycloadducts 3 and the trapping products 6. The preferred reaction mode has been found to be sensitive to steric effects. The product distribution is rationalized in terms of the diastereomeric 1,4-zwitterionic epoxonium intermediates syn- and anti-C, which are proposed to arise from a side-differentiated S(N)2 attack of the enol ether double bond on the peroxide bond of the alpha-peroxy lactone 1 through a perpendicular spiro-configurated transition state geometry. When the alpha-peroxy lactone 1 approaches the enol ether 2 from the oxy-substituted side, the syn-C epoxonium intermediate is formed, which leads to the epoxide 4 after release of the corresponding alpha-lactone. The latter oligomerizes to the polyester 8 or is trapped in methanol as the alpha-methoxy acid 9. On the contrary, the anti-C epoxonium intermediate results by approach of the alpha-peroxy lactone 1 from the non-oxy-substituted side of the enol ether 2, but the electronic repulsion between the lone pairs of the epoxonium and enol ether oxygens leads by ring opening of the epoxonium species to the coiled 1,6-zwitterion (U conformation). The latter is too short-lived for stereorandomization and closes to the cycloadducts 3 under high retention of the initial enol ether configuration, but is sufficiently long-lived to be trapped in methanol stereoselectively in form of the adducts 6. These unprecedented results in the peroxide-olefin reaction are contrasted with the previously reported alpha-peroxy lactone 1 oxidation of alkenes. While the enol ethers 2 lead to the cycloadducts 3 with a high degree of stereoretention and the alkenes lead to extensive loss of the initial olefin geometry, for both trapping by methanol in form of the adducts 6 takes place, again with high stereoselectivity for the enol ethers but not for the alkenes. This mechanistic dichotomy requires different intermediates, namely, the epoxonium species C for the enol ethers and the stretched 1,6-dipole (W conformation) A for the alkenes, which both lead to the cycloadducts 3, the former by way of the coiled 1,6-dipole (U conformation) D. For the enol ethers the epoxonium intermediate C is the precursor to the epoxide, while for the alkenes an independent concerted ''butterfly'' transition state geometry B applies in the epoxidation.
• Dimethyldioxirane epoxidation of alkenes bearing two electron donating substituents.
  作者：Waldemar Adam、Lazaros Hadjarapoglou、Xiaoheng Wang

  DOI：10.1016/s0040-4039(00)79649-3

  日期：1991.3

  Various enol-type alkenes, such as 2,3-dimethylbenzodioxin (1), O-tetrabenzyl glycal (3), 1,2-bis(trimethylsilyloxy)cycloalkenes (9) were transformed in excellent yields to their labile epoxides by dimethyldioxirane (as acetone solution); the silyl ketene acetal 5 and 2-methyl-3-trimethylsilyloxybenzo[b]furan (7) gave the corresponding epoxide rearrangement products.