4,4'-dimethyl-3,4,3',4'-tetrahydro-[4,4']bichromenyl-2,2'-dione | 18435-76-2

• 分子结构分类: 有机化合物 - 苯丙烷和聚酮 - 3,4-二氢香豆素
• 英文名称: 4,4'-dimethyl-3,4,3',4'-tetrahydro-[4,4']bichromenyl-2,2'-dione
• 英文别名: 4-methyl-4-(4-methyl-2-oxo-3H-chromen-4-yl)-3H-chromen-2-one
• CAS: 18435-76-2
• 化学式: C₂₀H₁₈O₄
• 分子量: 322.361
• InChiKey: ZSZBMCDTSLNLCX-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.7
• 重原子数：
  24
• 可旋转键数：
  1
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.3
• 拓扑面积：
  52.6
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为产物：
  描述：

  4-甲基香豆素 在 盐酸育亨宾 、 lithium chloride 作用下， 以 甲醇 、 水 为溶剂， 反应 6.0h， 生成 4,4'-dimethyl-3,4,3',4'-tetrahydro-[4,4']bichromenyl-2,2'-dione 、 (R)-(+)-3,4-dihydro-4-methylcoumarin 、 3-(2-hydroxyphenyl)butyric acid 、 (S)-4-methylchroman-2-one 、 methyl 3-(2-hydroxyphenyl)butanoate
  参考文献：
  名称：

  Enantioselective Cathodic Reduction of 4-Methylcoumarin: Dependence of Selectivity on Reaction Conditions and Investigation of the Mechanism

  摘要：

  AbstractThe cathodic reduction of 4‐methylcoumarin (1) in acidic methanol/water in the presence of yohimbine leads to formation of a mixture of the hydrogenation product 4‐methyl‐3,4‐dihydrocoumarin (2), with an enantiomeric excess (ee) of (R)‐2of 0–67%, and the hydrodimer3. The relative yields of2and3and theeeof2depend on a number of experimental parameters such as pH, supporting electrolyte, working potential, and the concentrations of substrate and yohimbine, as demonstrated by a series of preparative‐scale experiments. In addition, a series of voltammetric and kinetic measurements were carried out to investigate the influence of the individual experimental parameters. Three mechanistic possibilities have been examined, and by combination of the analytical data with the results of the preparative experiments, a single model is put forward which is in accord with the available results. The main features of the mechanistic model can be summarized as follows: 1) under acidic conditions (pH 2–3) the electroactive species is a complex between1and H3O+, the reduction of which leads to an enolic radical; 2) this radical is not reduced at the working potential but tautomerizes into the more easily reduced keto radical or dimerizes; 3) the keto radical is reduced and further protonated; 4) the function of the yohimbineH+is to catalyze the tautomerization and enantioselectively protonate the final carbanion. Additionally, we conclude that the concentration of yohimbine in the immediate vicinity of the electrode is considerably higher than its stoichiometric concentration. Quantum chemical calculations demonstrate thatsiprotonation of the intermediate anion by yohimbineH+to give (R)‐2is energetically favored.

  DOI：

  10.1002/chem.19970031216

文献信息

• Enantioselective Cathodic Reduction of 4-Methylcoumarin: Dependence of Selectivity on Reaction Conditions and Investigation of the Mechanism
  作者：Merete Folmer Nielsen、Belen Batanero、Thorsten Löhl、Hans J. Schäfer、Ernst-Ulrich Würthwein、Roland Fröhlich

  DOI：10.1002/chem.19970031216

  日期：1997.12

  AbstractThe cathodic reduction of 4‐methylcoumarin (1) in acidic methanol/water in the presence of yohimbine leads to formation of a mixture of the hydrogenation product 4‐methyl‐3,4‐dihydrocoumarin (2), with an enantiomeric excess (ee) of (R)‐2of 0–67%, and the hydrodimer3. The relative yields of2and3and theeeof2depend on a number of experimental parameters such as pH, supporting electrolyte, working potential, and the concentrations of substrate and yohimbine, as demonstrated by a series of preparative‐scale experiments. In addition, a series of voltammetric and kinetic measurements were carried out to investigate the influence of the individual experimental parameters. Three mechanistic possibilities have been examined, and by combination of the analytical data with the results of the preparative experiments, a single model is put forward which is in accord with the available results. The main features of the mechanistic model can be summarized as follows: 1) under acidic conditions (pH 2–3) the electroactive species is a complex between1and H3O+, the reduction of which leads to an enolic radical; 2) this radical is not reduced at the working potential but tautomerizes into the more easily reduced keto radical or dimerizes; 3) the keto radical is reduced and further protonated; 4) the function of the yohimbineH+is to catalyze the tautomerization and enantioselectively protonate the final carbanion. Additionally, we conclude that the concentration of yohimbine in the immediate vicinity of the electrode is considerably higher than its stoichiometric concentration. Quantum chemical calculations demonstrate thatsiprotonation of the intermediate anion by yohimbineH+to give (R)‐2is energetically favored.