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以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12a～12d.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.
Starting from N-benzyl-4-piperidone and isopropylamine, a series of reactions such as double Mannich reaction, Wolf-Kishner reduction and Pd / C debenzylation gave 3-isopropyl-3,7- Heterobicyclo [3.3.1] nonane (9); Compound 9 is then reacted with 4 tert-butyloxycarbonyl (Boc) protected L-amino acids to form the corresponding amide, which is then deprotected to give four new chiral bispeptides Amine compounds 12a-12d, which combine with Ni (acac) 2 to form a complex, are used as catalysts for the asymmetric 1,4-addition of diethylzinc to α, β-unsaturated ketones. The space structure of chiral ligands, the ratio and amount of ligand to nickel source, the reaction solvent and the reaction temperature on the reaction selectivity were investigated. Under the optimal reaction conditions, ie acetonitrile (12%, 20%), As the chiral ligand, 7% nickel acetylacetonate as catalyst, the molar ratio of diethylzinc to chalcone is 1.5: 1, diethylzinc (150%) and chalcone 1,4-co The yoke addition reaction product had a yield of 87% and an enantiomeric excess (ee) of 77%. The reason for the asymmetric addition reaction was discussed.