trans-1-<(R)-1-Phenylethyl>-3-<(E)-1-propenyl>-4-(2-pyridyl)-2-azetidinone

• 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: trans-1-<(R)-1-Phenylethyl>-3-<(E)-1-propenyl>-4-(2-pyridyl)-2-azetidinone
• 英文别名: (3R,4S)-1-[(1R)-1-phenylethyl]-3-[(E)-prop-1-enyl]-4-pyridin-2-ylazetidin-2-one
• 化学式: C₁₉H₂₀N₂O
• 分子量: 292.381
• InChiKey: VDWGALIVWCKMSK-RBYWTPTISA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.9
• 重原子数：
  22
• 可旋转键数：
  4
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.26
• 拓扑面积：
  33.2
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  methyl (E)-pent-3-enoate 、 (R,E)-N-(1-phenylethyl)-1-(pyridin-2-yl)methanimine 在 zinc(II) chloride 、 lithium diisopropyl amide 作用下， 生成 5-Methyl-1-<(R)-1-phenylethyl>-6-(2-pyridyl)-5,6-dihydropyridin-2-one 、 trans-1-<(R)-1-Phenylethyl>-3-<(E)-1-propenyl>-4-(2-pyridyl)-2-azetidinone
  参考文献：
  名称：

  Dualistic Reactivity of Lithium and Zinc Dienolates with Imines: Effects of Counterion, Temperature, and Substituents on .alpha.- and .gamma.-Coupling

  摘要：

  Lithium and zinc dienolates of 3-butenoic, 3-methyl-2-butenoic, 3-pentenoic, and 4-phenyl-3-butenoic methyl esters are reacted with imines R(1)C(H)=NR(2)[3a: R(1) = 2-pyridyl, R(2) = Ph; 3b: R(1) = Me(3)-SiC=C; R(2) = Ph; 3c: R(1) = 2-pyridyl, R(2) = (R)-PhCK(CH3); 3d: R(1) = Me(3)SiC=C; R(2) = (R)-PhCH(CH3)]. Depending on metal counterion, temperature, and substituents, the C-C coupling occurs either at the 2-position (alpha-coupling) or at the C-position (gamma-coupling) of the dienolate, giving beta-amino esters and alpha,beta-unsaturated esters, respectively. The alpha-coupling occurs at -78 degrees C and is reversible, whereas gamma-coupling products are formed upon warming to -20 degrees C. The C-C coupled products may undergo irreversible ring closure to beta-lactams (from beta-amino esters) or 5,6-dihydropyridin-2-ones (from Z)-alpha,beta-unsaturated esters). Starting from enantiomerically pure imine 3c, high (71-92%) asymmetric inductions were realized in both beta-lactams and 5,6-dihydropyridin-2-ones; gamma-coupling of enolate 2a and chiral imine 3d occurred with low diastereoselectivity (15%). Four factors favor the formation of beta-lactams: (i) the use of zinc dienolates, (ii) 4-substitution of the dienolates, (iii) nonaromatic imine N-substituents, and (iv) a low reaction temperature (-78 degrees C). The product formation is discussed in terms of six-membered cyclic transition states, involving either zinc enolates (alpha-coupling) or isomeric allylzinc species (gamma-coupling).

  DOI：

  10.1021/jo00104a048