4-ethyl-1-methyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one | 260060-74-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 萘并吡喃类
• 英文名称: 4-ethyl-1-methyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one
• 英文别名: (P)-4-ethyl-1-methyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one；(M)-4-ethyl-1-methyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one；4-Ethyl-1-methylnaphtho[2,1-c]chromen-6-one
• CAS: 260060-74-0
• 化学式: C₂₀H₁₆O₂
• 分子量: 288.346
• InChiKey: XHLPRWRVJLLMNT-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.4
• 重原子数：
  22
• 可旋转键数：
  1
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.15
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  2-乙基-5-甲基苯酚 在 palladium diacetate 、 sodium acetate 、 sodium hydride 、 三苯基膦 作用下， 以 四氢呋喃 、 N,N-二甲基乙酰胺 为溶剂， 反应 24.0h， 生成 4-ethyl-1-methyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one
  参考文献：
  名称：

  Atropisomerization Barriers of Configurationally Unstable Biaryl Compounds, Useful Substrates for Atroposelective Conversions to Axially Chiral Biaryls

  摘要：

  Configurationally unstable biaryl lactones of type (M)-1 reversible arrow (P)-1 and ring-opened 2-acyl-2'-hydroxy biaryl compounds of type (M)-4 reversible arrow (P)-4 are versatile precursors for the atroposelective preparation of axially chiral biaryls. The activation barriers of their atropisomerization process, which constitutes a fundamental precondition for the dynamic kinetic resolution, were determined by dynamic NMR spectroscopy for rapid processes and by HPLC-monitored racemization of enantiomerically enriched material for smaller interconversion rates. For the lactones, the free activation energies Delta G(298)(double dagger) increase with the steric demand of the substituent R ortho to the biaryl axis in the series H < OMe (t(1/2) approximate to ms) < Me (t(1/2) approximate to s) < Et < i-Pr (t(1/2) approximate to min) < t-Bu (t(1/2) approximate to d). The formally ring-opened 2-acyl-2'-hydroxy biaryls, which interconvert via the lactol isomers 5 as the cyclic (and thus configurationally less stable) intermediates, have a significantly slower atropisomerization rate as a result of the high loss in activation entropy Delta S-double dagger as a consequence of the required intermediate ring closure 4 --> 5.

  DOI：

  10.1021/jo9913356

文献信息

• Atropisomerization Barriers of Configurationally Unstable Biaryl Compounds, Useful Substrates for Atroposelective Conversions to Axially Chiral Biaryls
  作者：Gerhard Bringmann、Markus Heubes、Matthias Breuning、Lothar Göbel、Michael Ochse、Bernd Schöner、Olaf Schupp

  DOI：10.1021/jo9913356

  日期：2000.2.1

  Configurationally unstable biaryl lactones of type (M)-1 reversible arrow (P)-1 and ring-opened 2-acyl-2'-hydroxy biaryl compounds of type (M)-4 reversible arrow (P)-4 are versatile precursors for the atroposelective preparation of axially chiral biaryls. The activation barriers of their atropisomerization process, which constitutes a fundamental precondition for the dynamic kinetic resolution, were determined by dynamic NMR spectroscopy for rapid processes and by HPLC-monitored racemization of enantiomerically enriched material for smaller interconversion rates. For the lactones, the free activation energies Delta G(298)(double dagger) increase with the steric demand of the substituent R ortho to the biaryl axis in the series H < OMe (t(1/2) approximate to ms) < Me (t(1/2) approximate to s) < Et < i-Pr (t(1/2) approximate to min) < t-Bu (t(1/2) approximate to d). The formally ring-opened 2-acyl-2'-hydroxy biaryls, which interconvert via the lactol isomers 5 as the cyclic (and thus configurationally less stable) intermediates, have a significantly slower atropisomerization rate as a result of the high loss in activation entropy Delta S-double dagger as a consequence of the required intermediate ring closure 4 --> 5.