6-methoxy-3-methyl-3,3a,6,6a-tetrahydro-4H-furo[3,4-c]pyrazol-4-one

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 内酯类
• 英文名称: 6-methoxy-3-methyl-3,3a,6,6a-tetrahydro-4H-furo[3,4-c]pyrazol-4-one
• 英文别名: (3S,3aS,6R,6aR)-6-methoxy-3-methyl-3,3a,6,6a-tetrahydrofuro[3,4-c]pyrazol-4-one
• 化学式: C₇H₁₀N₂O₃
• 分子量: 170.168
• InChiKey: VWVRGCKEXSLBBI-MEOJTODESA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.1
• 重原子数：
  12
• 可旋转键数：
  1
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.86
• 拓扑面积：
  60.2
• 氢给体数：
  0
• 氢受体数：
  5

反应信息

• 作为产物：
  描述：

  重氮乙烷 、 5-甲氧基呋喃-2(5h)-酮 以 乙醚 为溶剂， 反应 1.5h， 以41%的产率得到4-methoxy-3-methyl-3,3a,4,6a-tetrahydro-6H-furo[3,4-c]pyrazol-6-one
  参考文献：
  名称：

  The Role of Steric and Electronic Interactions in the Stereocontrol of the Asymmetric 1,3-Dipolar Reactions of 5-Ethoxy-3-p-(S)-tolylsulfinylfuran-2(5H)-ones with Diazoalkanes:  Theoretical Calculations and Experimental Evidences

  摘要：

  The addition of diazomethane and diazoethane to (5S,SS)- and (5R,SS)-5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones (1a and 1B) and their 4-methylderivatives (2a and 2b) proceeded in almost quantitative yields and complete regioselectivity. The observed pi-facial selectivity is determined by the configurations at both C-5 and the sulfinyl group, the later being the most important. The syn adducts were almost exclusively obtained from 1a and 2a in apolar solvents but the pi-facial selectivity was strongly decreased in more polar solvents. On the other hand, the major adducts from 1b and 2b were the anti ones and such predominance was slightly increased with solvent polarity. The exo-selectivity was complete in all the cases except for the anti approach to compounds 2a (in polar solvents) and 2b. The role of the sulfinyl group in this behavior was inferred by comparison of these results with those obtained in reactions of diazoalkanes with 5-methoxyfuran-2(5H)-one (3). Steric interactions seem to be the main ones responsible for the observed exo selectivity of reactions with diazoethane, but electronic factors, which can be modulated by the solvent, are also significant in the pi-facial selectivity control. DFT computational methods are able to correctly predict the reactivity, regioselectivity, and pi-facial selectivity exhibited by 5-alkoxy-furanones as well as their changes with the solvent polarity. A C-H...O hydrogen bond, involving the oxygen atom of the 5-alkoxy group at dipolarophiles and the endo-hydrogen atom at dipoles, seems to play a key role in the electronic interactions influencing the stereochemical course of these reactions.

  DOI：

  10.1021/jo0345603

文献信息

• The Role of Steric and Electronic Interactions in the Stereocontrol of the Asymmetric 1,3-Dipolar Reactions of 5-Ethoxy-3-<i>p</i>-(<i>S</i>)-tolylsulfinylfuran-2(5<i>H</i>)-ones with Diazoalkanes:  Theoretical Calculations and Experimental Evidences
  作者：José L. García Ruano、Alberto Fraile、Gemma González、M. Rosario Martín、Fernando R. Clemente、Ruth Gordillo

  DOI：10.1021/jo0345603

  日期：2003.8.1

  The addition of diazomethane and diazoethane to (5S,SS)- and (5R,SS)-5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones (1a and 1B) and their 4-methylderivatives (2a and 2b) proceeded in almost quantitative yields and complete regioselectivity. The observed pi-facial selectivity is determined by the configurations at both C-5 and the sulfinyl group, the later being the most important. The syn adducts were almost exclusively obtained from 1a and 2a in apolar solvents but the pi-facial selectivity was strongly decreased in more polar solvents. On the other hand, the major adducts from 1b and 2b were the anti ones and such predominance was slightly increased with solvent polarity. The exo-selectivity was complete in all the cases except for the anti approach to compounds 2a (in polar solvents) and 2b. The role of the sulfinyl group in this behavior was inferred by comparison of these results with those obtained in reactions of diazoalkanes with 5-methoxyfuran-2(5H)-one (3). Steric interactions seem to be the main ones responsible for the observed exo selectivity of reactions with diazoethane, but electronic factors, which can be modulated by the solvent, are also significant in the pi-facial selectivity control. DFT computational methods are able to correctly predict the reactivity, regioselectivity, and pi-facial selectivity exhibited by 5-alkoxy-furanones as well as their changes with the solvent polarity. A C-H...O hydrogen bond, involving the oxygen atom of the 5-alkoxy group at dipolarophiles and the endo-hydrogen atom at dipoles, seems to play a key role in the electronic interactions influencing the stereochemical course of these reactions.