(3S,4S)-1-Benzyl-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((S)-1-hydroxy-ethyl)-azetidin-2-one | 194367-29-8

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 内酰胺类
• 英文名称: (3S,4S)-1-Benzyl-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((S)-1-hydroxy-ethyl)-azetidin-2-one
• 英文别名: (3S,4S)-1-benzyl-3-[(1R)-1-[tert-butyl(dimethyl)silyl]oxyethyl]-4-[(1S)-1-hydroxyethyl]azetidin-2-one
• CAS: 194367-29-8
• 化学式: C₂₀H₃₃NO₃Si
• 分子量: 363.572
• InChiKey: CSOHZBVYNWHQOC-BURFUSLBSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.8
• 重原子数：
  25
• 可旋转键数：
  7
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.65
• 拓扑面积：
  49.8
• 氢给体数：
  1
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  (3S,4S)-1-Benzyl-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((S)-1-hydroxy-ethyl)-azetidin-2-one 在 四氯化碳 、 三苯基膦 作用下， 反应 24.0h， 生成 (3S,4S)-1-Benzyl-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((R)-1-chloro-ethyl)-azetidin-2-one
  参考文献：
  名称：

  Highly Diastereoselective Conjugate Addition of Lithium Dialkylamides to α,β-Unsaturated Esters Having a Chiral Center at the γ-Position

  摘要：

  The conjugate addition of lithium amides 2 to tert-butyl 4-(OR)-substituted-2-pentenoates 1 produced a mixture of the syn-and anti-amino esters (3 and 4) in high yields. Sterically bulky OR groups, such as trityloxy and tert-butyldiphenylsilyloxy, gave the syn diastereomer 3 either exclusively or predominantly. The syn-selectivity may be explained by a modified Felkin-Anh model. The use of tert-butyldimethylsilyloxy as an OR group afforded a nearly 1:1 mixture of diastereoisomers, and the use of the smallest MeO group produced a 63:37 mixture of the syn 3 and anti isomer 4. The presence of Me group at the alpha-position (C-2 position) of the enoate enhanced the syn diastereoselectivity up to 100%; the conjugate addition to tert-butyl 4-methoxy-2-methyl-2-pentenoate (17) gave the syn-isomer 18 exclusively. This enhancement may be explained by the combination of chelation and allylic strain model 19 in which the smallest H orients inside to avoid an allylic strain. A phenyl group at the gamma-position enhanced the anti selectivity in the case of gamma-alkoxy-alpha,beta-enoates such as isopropyl 4-[(tert-butyldimethylsilyl)oxy]-4-phenyl-2-buteonoate (20), and in the case of gamma-alkyl-alpha,beta-enoates such as tert-butyl 4-phenyl-2-pentenoate (27).

  DOI：

  10.1021/jo970435d
• 作为产物：
  描述：

  tert-butyl (3S,4S)-3-(benzylamino)-4-trityloxypentanoate 在 咪唑 、 甲酸 、 乙基溴化镁 、 lithium diisopropyl amide 作用下， 以 四氢呋喃 、 乙醚 、 二氯甲烷 为溶剂， 反应 5.95h， 生成 (3S,4S)-1-Benzyl-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((S)-1-hydroxy-ethyl)-azetidin-2-one
  参考文献：
  名称：

  Highly Diastereoselective Conjugate Addition of Lithium Dialkylamides to α,β-Unsaturated Esters Having a Chiral Center at the γ-Position

  摘要：

  The conjugate addition of lithium amides 2 to tert-butyl 4-(OR)-substituted-2-pentenoates 1 produced a mixture of the syn-and anti-amino esters (3 and 4) in high yields. Sterically bulky OR groups, such as trityloxy and tert-butyldiphenylsilyloxy, gave the syn diastereomer 3 either exclusively or predominantly. The syn-selectivity may be explained by a modified Felkin-Anh model. The use of tert-butyldimethylsilyloxy as an OR group afforded a nearly 1:1 mixture of diastereoisomers, and the use of the smallest MeO group produced a 63:37 mixture of the syn 3 and anti isomer 4. The presence of Me group at the alpha-position (C-2 position) of the enoate enhanced the syn diastereoselectivity up to 100%; the conjugate addition to tert-butyl 4-methoxy-2-methyl-2-pentenoate (17) gave the syn-isomer 18 exclusively. This enhancement may be explained by the combination of chelation and allylic strain model 19 in which the smallest H orients inside to avoid an allylic strain. A phenyl group at the gamma-position enhanced the anti selectivity in the case of gamma-alkoxy-alpha,beta-enoates such as isopropyl 4-[(tert-butyldimethylsilyl)oxy]-4-phenyl-2-buteonoate (20), and in the case of gamma-alkyl-alpha,beta-enoates such as tert-butyl 4-phenyl-2-pentenoate (27).

  DOI：

  10.1021/jo970435d