有机化学 ›› 2011, Vol. 31 ›› Issue (04): 497-504. 上一篇    下一篇

研究论文

手性双哌啶酰胺的合成及在共轭加成中的应用

石乃月,高敬园,张月成*,赵继全   

  1. (河北工业大学化工学院 天津 300130)
  • 收稿日期:2010-07-15 修回日期:2010-09-26 发布日期:2010-11-23
  • 通讯作者: 张月成 E-mail:yczhang@hebut.edu.cn

Synthesis of Chiral Amides Emodying the Bispidine Framwork and Their Application in 1,4-Addition Reaction

SHI Nai-Yue, GAO Jing-Yuan, ZHANG Yue-Cheng, ZHAO Ji-Quan   

  1. (School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130)
  • Received:2010-07-15 Revised:2010-09-26 Published:2010-11-23

N-苄基-4-哌啶酮、异丙胺为初始原料, 经双Mannich反应、Wolf-Kishner还原、Pd/C脱苄基一系列反应得到3-异丙基-3,7-二氮杂双环[3.3.1]壬烷(9)|化合物9再与4个叔丁氧羰基(Boc)保护的L-氨基酸反应生成相应酰胺, 然后脱Boc保护基得到四个新的手性双哌啶α-氨基酰胺化合物12a12d. 它们与Ni(acac)2结合形成配合物, 用作二乙基锌对α,β-不饱和酮的不对称1,4-加成反应的催化剂. 考察了手性配体的空间结构、配体与镍源的比例及用量、反应溶剂和反应温度对反应选择性的影响. 在优化的反应条件下, 即: 以乙腈为溶剂, 12c (20%)为手性配体, 7%的乙酰丙酮镍为催化剂, 二乙基锌与查尔酮的物质的量比为1.5∶1, 二乙基锌(150%)与查尔酮1,4-共轭加成反应产物的收率为87%, 对映体过量值(ee)为77%. 探讨了产生不对称加成反应的原因.

关键词: N-苄基-4-哌啶酮, 双哌啶, 氨基酸, 二乙基锌, 手性酰胺, 不对称1,4-共轭加成

3-Isopropyl-3,7-diazabicyclo[3.3.1]nonane 9 was conveniently synthesized from N-benzyl- 4-piperidinone and isopropyl amine via double Mannich reaction, Wolff-Kishner reduction, debenzylation through Pd/C catalyzed hydrogenation. Subsequently, compound 9 was reacted with four N-tert-butoxycarbonyl-L-amino acids, followed by deprotection of tert-butoxycarbonyl group, to generate four new chiral α-amino amide ligends 12a12d. They were used in Ni-catalyzed enantioselective 1,4-conjugate addition of diethyl zinc to α,β-unsaturated ketones. The effects of steric properties of chiral ligands, molar ratio of chiral ligand to nickel source, loading amount of ligand, solvent and temperature on 1,4-conjugate addition were investigated. Under the optimized conditions: MeCN as solvent, 12c (20 mol%) as ligand, Ni(acac)2 (7 mol%), Et2Zn (150%), a yield of 87% and an enantioselectivity of 77% were obtained, respectively. The possible mechanism for the asymmetric addition reactions was discussed.

Key words: N-benzyl-4-piperidinone, bispidine, amino acid, diethyl zinc, chiral amide, enantioselective 1,4-conjugate addition