1-ethoxy-2,3-dicarbomethoxy-6,6-dimethyl-7-oxabicyclo<2.2.1>heptan-5-one | 133374-47-7

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 1-ethoxy-2,3-dicarbomethoxy-6,6-dimethyl-7-oxabicyclo<2.2.1>heptan-5-one
• CAS: 133374-47-7
• 化学式: C₁₄H₁₈O₇
• 分子量: 298.293
• InChiKey: FSAPNVLLKRVYJN-UHFFFAOYSA-N

反应信息

• 作为产物：
  描述：

  ethyl 4-diazo-2,2-dimethyl-3-oxobutyrate 、 丁炔二酸二甲酯 在 dirhodium tetraacetate 作用下， 以 苯 为溶剂， 反应 0.5h， 以74%的产率得到1-ethoxy-2,3-dicarbomethoxy-6,6-dimethyl-7-oxabicyclo<2.2.1>heptan-5-one
  参考文献：
  名称：

  Tandem cyclization-cycloaddition reaction of rhodium carbenoids. Studies dealing with the geometric requirements of dipole formation

  摘要：

  The carbenoid intermediate derived by the treatment of several 1-diazobutanediones with rhodium(II) acetate undergoes ready transannular cyclization onto the neighboring keto group to give five-membered ring carbonyl ylides. The dipole derived from ethyl 4-diazo-2-methyl-3-oxobutyrate was found to undergo a rapid proton transfer, producing 5-ethoxy-4-methyl-3-(2H)-furanone. When the position adjacent to the diazo carbonyl group is blocked with two substituent groups, however, smooth 1,3-dipolar cycloaddition occurs. The observed regioselectivity can be nicely accommodated in terms of frontier molecular orbital (FMO) theory. A type II FMO interaction is involved since carbonyl ylides possess one of the smallest HOMO-LUMO energy gaps of common 1,3-dipoles. The rhodium(II)-catalyzed reaction of 1-diazo-6-phenyl-2,6-hexanedione afforded a mixture of products. In addition to the expected cycloadduct, a product derived from the bimolecular addition of the rhodium carbenoid to benzene was obtained. The formation of a mixture of products in this case suggests that entropic factors have sufficiently retarded the rate of intramolecular cyclization so as to allow the bimolecular reaction with benzene to occur. No observable cycloadduct was obtained from the diazohexanedione system, thereby indicating that the longer tether was sufficient to shut down dipole formation.

  DOI：

  10.1021/jo00010a019