8-carbomethoxy-7-(diethylamino)-2-oxabicyclo<4.2.0>oct-7-en-4-on

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 氧烷类
• 英文名称: 8-carbomethoxy-7-(diethylamino)-2-oxabicyclo<4.2.0>oct-7-en-4-on
• 英文别名: Methyl 7-(diethylamino)-4-oxo-2-oxabicyclo[4.2.0]oct-7-ene-8-carboxylate
• 化学式: C₁₃H₁₉NO₄
• 分子量: 253.298
• InChiKey: AOIKZAYMWBPOKJ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.3
• 重原子数：
  18
• 可旋转键数：
  5
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.69
• 拓扑面积：
  55.8
• 氢给体数：
  0
• 氢受体数：
  5

反应信息

• 作为产物：
  描述：

  1-diazo-5-(diethylamino)pentane-2,5-dione 、 丙炔酸甲酯 在 rhodium(II) acetate dimer 作用下， 以 氯仿 为溶剂， 以10%的产率得到6-carbomethoxy-5-hydroxy-3-oxabicyclo<3.2.1>oct-6-ene-2-one
  参考文献：
  名称：

  A Novel Cycloaddition Reaction of α-Diazo-γ-amido Ketones Catalyzed by Rhodium(II) Acetate. Scope and Mechanistic Details of the Process

  摘要：

  alpha-Diazo ketones containing an amido group in the gamma-position have been found to undergo a novel rhodium(II)-catalyzed cycloaddition reaction. Intramolecular cyclization of the keto carbenoid onto the oxygen atom of the amide group generates a carbonyl ylide dipole as a transient species. This highly stabilized dipole does not readily undergo 1,3-dipolar cycloaddition but rather transfers a proton to produce a cyclic ketene N,O-acetal. The ketene acetal is unstable to moisture and upon standing is readily hydrolyzed to a gamma-keto delta-lactone and an amine. In the absence of any significant amount of water, the ketene N,O-acetal undergoes conjugate addition with the activated st-bond of the dipolarophile to give a zwitterion intermediate. The anionic portion of the zwitterion adds to the neighboring carbonyl group. This is followed by epoxide ring formation with charge dissipation leading to an amido-substituted spiro cyclopentyl epoxide. In certain cases a hydroxy lactone was also isolated and its formation can be attributed to the competitive hydrolysis of the zwitterionic intermediate. The Rh(II)-catalyzed reaction of the diazo ketoamide derived from N-benzylpiperidone with DMAD afforded two different types of cycloadducts. In addition to the spiro cyclopentyl epoxide, a product derived from trapping of the carbonyl ylide dipole was also obtained, thereby providing additional support for the proposed mechanism.

  DOI：

  10.1021/jo952078h

文献信息

• A Novel Cycloaddition Reaction of α-Diazo-γ-amido Ketones Catalyzed by Rhodium(II) Acetate. Scope and Mechanistic Details of the Process
  作者：Albert Padwa、Alan T. Price、Lin Zhi

  DOI：10.1021/jo952078h

  日期：1996.1.1

  alpha-Diazo ketones containing an amido group in the gamma-position have been found to undergo a novel rhodium(II)-catalyzed cycloaddition reaction. Intramolecular cyclization of the keto carbenoid onto the oxygen atom of the amide group generates a carbonyl ylide dipole as a transient species. This highly stabilized dipole does not readily undergo 1,3-dipolar cycloaddition but rather transfers a proton to produce a cyclic ketene N,O-acetal. The ketene acetal is unstable to moisture and upon standing is readily hydrolyzed to a gamma-keto delta-lactone and an amine. In the absence of any significant amount of water, the ketene N,O-acetal undergoes conjugate addition with the activated st-bond of the dipolarophile to give a zwitterion intermediate. The anionic portion of the zwitterion adds to the neighboring carbonyl group. This is followed by epoxide ring formation with charge dissipation leading to an amido-substituted spiro cyclopentyl epoxide. In certain cases a hydroxy lactone was also isolated and its formation can be attributed to the competitive hydrolysis of the zwitterionic intermediate. The Rh(II)-catalyzed reaction of the diazo ketoamide derived from N-benzylpiperidone with DMAD afforded two different types of cycloadducts. In addition to the spiro cyclopentyl epoxide, a product derived from trapping of the carbonyl ylide dipole was also obtained, thereby providing additional support for the proposed mechanism.