Different Michael addition reactions catalyzed by solid base K2O/γ-Al2O3 and KF/γ-Al2O3,MgO/γ-Al2O3 prepared by microwave irradiation method were reported in this paper.For the K2O/γ-Al2O3,not only good yield was ...Different Michael addition reactions catalyzed by solid base K2O/γ-Al2O3 and KF/γ-Al2O3,MgO/γ-Al2O3 prepared by microwave irradiation method were reported in this paper.For the K2O/γ-Al2O3,not only good yield was attained but also made the reaction of Acetonitrile that usually is regarded as inactive carbonion and α,β-unsaturated compound to carry out.The yield of Michael reaction of Ethyl acetoacetate and Crotonaldehyde catalyzed by KF/γ-Al2O3,MgO/γ-Al2O3,MgO/NaY all could reach to 80% and the latter could reach to 90%.At the same time,the catalysts of different content（the ratio of load）of MgO were also applied in this reaction,and it was found that the best content of MgO was 20%～25%.展开更多
含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环...含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环化串联反应。筛选出最佳的催化剂体系为:10 mol%金鸡纳碱衍生物催化剂1f,二氯甲烷(1 m L)为溶剂,室温反应。将最佳条件用于不同取代靛红的反应,以80~88%的产率和最高达96%的对映选择性获得了螺[羟吲哚-3,4′-吡喃色烯]化合物。本研究拓宽了该反应的催化剂类型和底物范围。展开更多
In this paper, we report the tandem Michael addition-elimination reactions of chiral 5-alkoxy-3,4-dihalo-2（5H）-furanones with DMF by the catalyst of metal sodium. The optically pure 5-（S）-alkoxy-4-N,N-dimethyl-3-h...In this paper, we report the tandem Michael addition-elimination reactions of chiral 5-alkoxy-3,4-dihalo-2（5H）-furanones with DMF by the catalyst of metal sodium. The optically pure 5-（S）-alkoxy-4-N,N-dimethyl-3-halo-2（5H）-furanones 6a6d were identified on the basis of their analytical data, such as [α]20D , UV, IR, 1H NMR, 13C NMR, MS and elemental analysis.展开更多
It is one of the most attractive types of asymmetric synthesis that chiral commpounts are generated under the influence of chiral catalysts. In recent years catalytic asymmetric Michael addition by chiral metal comple...It is one of the most attractive types of asymmetric synthesis that chiral commpounts are generated under the influence of chiral catalysts. In recent years catalytic asymmetric Michael addition by chiral metal complexes has been recognized as an efficient method for obtaining asymmetric products. In this work we reported that using potassium thiazolidine -2-thione-4-carboxylate [(R)-TTCA·K] as the chiral catalyst, the addition reaction of cyclohexanone with acrylonitrile was carried out and optically active (S)-(+)-2-cyanoethyl cyclohexanone 1 ([α] 20 D=+2.8°, e.e. 19%) and hydrolysis product of 1, (S)-(-)-2-oxocyclohexanepropionic acid 2 ([α] 20 D=-2.95°, e.e. 19%), were obtained. Enantiomeric excess of compound 1 was determined by resolution of (R,S)-2-oxocyclohexanepropionic acid with (-)-quinine. Compounds 1 and 2 were easily racemized at a long time for laying aside and in the presence of dil H 2SO 4 or dil base. When (S)-(+)-2-cyanoethyl cyclohexanone reacts with ethylene glycol in the presence of toluene sulfonic acid as the catalyst the racemic 2-ethylendioxy cyclohexyl propionitrile was obtained. The mechanism of the reaction of cyclohexanone with acrylonitrile would be a complicated catalysis process.展开更多
The asymmetric Michael addition-elimination reaction of chiral 5-(1S)-bornyloxy-3,4-dibromo-2(5H)furanones and some amines are investigated.Four new chiral bornyl amine derivatives 6a～6d are obtained.they are identif...The asymmetric Michael addition-elimination reaction of chiral 5-(1S)-bornyloxy-3,4-dibromo-2(5H)furanones and some amines are investigated.Four new chiral bornyl amine derivatives 6a～6d are obtained.they are identified by IR,1H NMR,13C NMR,HRMS and so on.It offer a new way to synthetize more chiral bornyl amine derivatives.展开更多
文摘Different Michael addition reactions catalyzed by solid base K2O/γ-Al2O3 and KF/γ-Al2O3,MgO/γ-Al2O3 prepared by microwave irradiation method were reported in this paper.For the K2O/γ-Al2O3,not only good yield was attained but also made the reaction of Acetonitrile that usually is regarded as inactive carbonion and α,β-unsaturated compound to carry out.The yield of Michael reaction of Ethyl acetoacetate and Crotonaldehyde catalyzed by KF/γ-Al2O3,MgO/γ-Al2O3,MgO/NaY all could reach to 80% and the latter could reach to 90%.At the same time,the catalysts of different content（the ratio of load）of MgO were also applied in this reaction,and it was found that the best content of MgO was 20%～25%.
文摘含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环化串联反应。筛选出最佳的催化剂体系为:10 mol%金鸡纳碱衍生物催化剂1f,二氯甲烷(1 m L)为溶剂,室温反应。将最佳条件用于不同取代靛红的反应,以80~88%的产率和最高达96%的对映选择性获得了螺[羟吲哚-3,4′-吡喃色烯]化合物。本研究拓宽了该反应的催化剂类型和底物范围。
文摘In this paper, we report the tandem Michael addition-elimination reactions of chiral 5-alkoxy-3,4-dihalo-2（5H）-furanones with DMF by the catalyst of metal sodium. The optically pure 5-（S）-alkoxy-4-N,N-dimethyl-3-halo-2（5H）-furanones 6a6d were identified on the basis of their analytical data, such as [α]20D , UV, IR, 1H NMR, 13C NMR, MS and elemental analysis.
文摘It is one of the most attractive types of asymmetric synthesis that chiral commpounts are generated under the influence of chiral catalysts. In recent years catalytic asymmetric Michael addition by chiral metal complexes has been recognized as an efficient method for obtaining asymmetric products. In this work we reported that using potassium thiazolidine -2-thione-4-carboxylate [(R)-TTCA·K] as the chiral catalyst, the addition reaction of cyclohexanone with acrylonitrile was carried out and optically active (S)-(+)-2-cyanoethyl cyclohexanone 1 ([α] 20 D=+2.8°, e.e. 19%) and hydrolysis product of 1, (S)-(-)-2-oxocyclohexanepropionic acid 2 ([α] 20 D=-2.95°, e.e. 19%), were obtained. Enantiomeric excess of compound 1 was determined by resolution of (R,S)-2-oxocyclohexanepropionic acid with (-)-quinine. Compounds 1 and 2 were easily racemized at a long time for laying aside and in the presence of dil H 2SO 4 or dil base. When (S)-(+)-2-cyanoethyl cyclohexanone reacts with ethylene glycol in the presence of toluene sulfonic acid as the catalyst the racemic 2-ethylendioxy cyclohexyl propionitrile was obtained. The mechanism of the reaction of cyclohexanone with acrylonitrile would be a complicated catalysis process.
文摘The asymmetric Michael addition-elimination reaction of chiral 5-(1S)-bornyloxy-3,4-dibromo-2(5H)furanones and some amines are investigated.Four new chiral bornyl amine derivatives 6a～6d are obtained.they are identified by IR,1H NMR,13C NMR,HRMS and so on.It offer a new way to synthetize more chiral bornyl amine derivatives.
