(S)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)-2-sec-butylpyrrolidine-2-carboxylic acid | 1012059-18-5

• 分子结构分类: 有机化合物 - 苯类化合物 - 芴
• 英文名称: (S)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)-2-sec-butylpyrrolidine-2-carboxylic acid
• 英文别名: (2S)-2-[(2S)-butan-2-yl]-1-(9H-fluoren-9-ylmethoxycarbonyl)pyrrolidine-2-carboxylic acid
• CAS: 1012059-18-5
• 化学式: C₂₄H₂₇NO₄
• 分子量: 393.483
• InChiKey: VAHDNZDQXUZCCU-FYSMJZIKSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  4.9
• 重原子数：
  29
• 可旋转键数：
  6
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.42
• 拓扑面积：
  66.8
• 氢给体数：
  1
• 氢受体数：
  4

反应信息

• 作为产物：
  描述：

  在 盐酸 作用下， 反应 24.0h， 以3.20 g的产率得到(S)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)-2-sec-butylpyrrolidine-2-carboxylic acid
  参考文献：
  名称：

  Powdered KOH in DMSO:  An Efficient Base for Asymmetric Cyclization via Memory of Chirality at Ambient Temperature

  摘要：

  Enolate chemistry has been extensively used for stereoselective C-C bond formation, in which metal amide bases are frequently employed in strictly anhydrous solvents at low temperatures. However, we found that asymmetric intramolecular C-C bond formation via axially chiral enolate intermediates proceeded in up to 99% ee at 20 degrees C using powdered KOH in dry or wet DMSO as a base. The enantioselectivity was even higher than that of the corresponding reactions with potassium hexamethyldisilazide in DIVIF at -60 degrees C. The racemization barrier of the axially chiral enolate intermediate was estimated to be similar to 15.5 kcal/mol. On the basis of the barrier, the chiral enolate intermediate was supposed to undergo cyclization within similar to 10(-3) sec at 20 degrees C after it is generated to give the product in 2 >= 99% ee. Thus, enolates generated with powdered KOH in DMSO were expected to be extremely reactive.

  DOI：

  10.1021/ja077684w

文献信息

• Powdered KOH in DMSO:  An Efficient Base for Asymmetric Cyclization via Memory of Chirality at Ambient Temperature
  作者：Takeo Kawabata、Katsuhiko Moriyama、Shimpei Kawakami、Kazunori Tsubaki

  DOI：10.1021/ja077684w

  日期：2008.3.1

  Enolate chemistry has been extensively used for stereoselective C-C bond formation, in which metal amide bases are frequently employed in strictly anhydrous solvents at low temperatures. However, we found that asymmetric intramolecular C-C bond formation via axially chiral enolate intermediates proceeded in up to 99% ee at 20 degrees C using powdered KOH in dry or wet DMSO as a base. The enantioselectivity was even higher than that of the corresponding reactions with potassium hexamethyldisilazide in DIVIF at -60 degrees C. The racemization barrier of the axially chiral enolate intermediate was estimated to be similar to 15.5 kcal/mol. On the basis of the barrier, the chiral enolate intermediate was supposed to undergo cyclization within similar to 10(-3) sec at 20 degrees C after it is generated to give the product in 2 >= 99% ee. Thus, enolates generated with powdered KOH in DMSO were expected to be extremely reactive.