摘要
1.用NaBH_4对潜手性酮的不对称还原可用β-环糊精(β-CD)诱导。生成的手性醇最高e.e.％为41.9。手性醇的旋光方向很可能与酮的结构类型有关。在β-CD存在时,用NaBH_4还原疏水性酮的产率亦有提高;2.用金属-麻黄素,金属-N-甲基麻黄素,金属-β-CD,金属-麻黄素-β-CD,金属-N-甲基麻黄素-β-CD体系可催化p-硝基苯甲醛与丙酮的醇酮缩合。在温和中性条件下,得到对映体过量的醇酮型产物4-羟基-4-(4-硝基苯基)-2-丁酮,在水介质中,最高产率为82.8％,最高比旋光度为[α]_D^(15)+12.5。m-硝基苯甲醛与丙酮的醇酮缩合情况与p-硝基苯甲醛类似;3.在β-CD存在下,从相应的醛合成了α-芳基甘氨酸。产生的α-芳基甘氨酸具有光学活性。最高产率为84.5％。并研究了在相似反应条件下α-羟基芳基乙酸的合成。所有的反应均“一锅”完成。
1. The asymmetric redution of prochiral ketones with NaBH4 can be induced by β-CD. In the produced chiral alcohols the highest e. e% is 41. 9. The direction of optical rotation of the chiral alcohol is probably dependent on the type of the ketone structure. The yield of hydrophobic ketone redution by NaBH4 is improved in the presence of β-CD. 2. The aldol condensation of p-nitrobenzaldehyde with acetone is catalyzed by Metal1-ephedrine,Metal1 -N-methylephedrine,Metal1 -β-CD,Metal1 -ephedrine-β-CD, Metal1 -N-methylephedrine-β-CD systems. The enantiametric excess aldol type product 4-hydroxy-4-(4-nitropnenyl)-2-butanone is achivevd under the mild and neutral condition. In water media the highest yield is 82. 8% and the highest specific rotation [a]b5 + 12. 5. The aldol condensations of m-nitrobenzaldehyde with acetone are similar to those cases of p-Nitroben-zaldehyde. 3. α-arylglycines are synthesized from corresponding aldehydes in the presence of β-CD. The resulting α-arylglycines have optical rotation. The highest yield is 84. 5%. Moreover,under similar reaction condition the synthesis of α-hydroxy-arylacetic acids are studied. All of reactions are completed in one-pot.
关键词
Β-环糊精
醇酮缩合
合成效应
β-cyclodextrin
α-arylglycines
α-hydroxy-arylacetic acids
synthesis
asymmetric inductions
ketone reductions
aldol condensation
