高分子(纤维)负载手性氨基醇的合成及其催化二乙基锌对苯甲醛的不对称加成

合成了一种高分子纤维负载手性氨基醇催化剂, 并将该高分子纤维负载手性氨基醇用于催化二乙基锌对苯甲醛的对映选择性加成反应, 发现高分子纤维负载的手性氨基醇比树脂负载手性氨基醇的催化效果要好, 所得产物化学收率提高34%, 光学收率提高近9%. 该高分子纤维负载手性氨基醇可重复使用5次以上. 用比较纤维催化剂在催化反应前后的SEM照片方法, 证实了重复使用时催化效率下降的原因是有部分催化剂流失.     

The Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by 2-Methylquinoline Derived Chiral Ligands

One of the most important and fundamental synthetic procedures for the establishment of a carbon-carbon bond stereoselectively is the enantioselective addition of organometallic reagents to aldehydes affording chiral secondary alcohols1. In this process, a frequently used method is to perform the reaction in the presence of a chiral ligand such as amino alcohol2. Here, we first report that two new chiral ligands3, which were readily available by the reaction of chiral ketone with lithiated 2-m…     

手性氨基酚催化二乙基锌对芳香醛的不对称加成反应

用易得的原料合成了4个手性氨基酚，这些化合物成功地催化了二乙基锌对醛 的不对称加成反应．其中1a催化间氯苯甲醛和二乙基锌的加成反应获得了较高的化 学产率(95％)和较好的ee值(57％)．     

水解酶在二乙基锌与芳香醛加成反应中的应用

报道了水解酶催化二乙基锌与芳香醛的加成反应,对反应条件进行了优化.在最适条件(嗜热酯酶APE1547为酶源,反应温度40℃,氯仿为溶剂,4-Cl-苯甲醛为底物)下,加成反应生成的光学活性醇产率最高达78%,ee值最高可达56%.通过实验结果和分子动力学分析对可能的反应机理进行了推测.本研究进一步拓展了酶的非专一性.     

Enantioselective Addition of Diethylzinc to Aromatic Aldehydes Catalyzed by New Chiral Oxazolidine Ligand

Abstract

The chiral oxazolidine ligand can catalyze the enantioselective addition of diethylzinc to aromatic aldehydes at room temperature with high enantioselectivity (98–99% ee). The conditions for this catalytic process are both mild and simple as compared with the same kind catalyst.     

Thiazolidine Derivatives as Chiral Catalysts in the Enantioselective Addition of Diethylzinc to Benzaldehyde

Enantioselective addition ofdialkylzinc to aldehydes in the presence of catalytic amountsof chiral catalysts is one of the most important asymmetric C-C bond formation reactions.In most cases chiral fi -amino alcohols or their analogies were used as efficient catalystsin this reactionl.Several chiral catalysts based on the thiazolidine ring have been reported, whichshowed moderate enantioselectivity'. While esters or their derivatives were seldom usedas efficient catalysts. But in our previou…     

L-半胱氨酸衍生物的合成及应用

以L-半胱氨酸为手性源，合成了二类多官能团的化合物6和7，并用于醛的不对 称烷基化反应，同时研究了催化剂的结构对反应结果的影响．     

Novel Chiral Ferrocenyl Aziridino Alcohol Catalysts Promoting Asymmetric Addition of Diethylzinc to Aldehydes

Optically active aziridino alcohols containing ferrocenyl groups were prepared from commercially available L-threonine in excellent yields and used as catalysts to promote the asymmetric addition of diethylzinc to aryaldehydes to afford 1-arylpropanol in up to 84% enantiomeric excesses with moderate to good yields.     

Enantioselective Diethylzinc Addition to Aromatic Aldehydes Catalyzed by Novel Ti(IV) Complex of Three-Dentate Chiral Sulfonamide Ligands

The synthesis of several novel three-dentate sulfonamide alcohol ligands is described, starting from camphorsulfonyl chloride. The influence of temperature and ligand structure on the asymmetric addition of dietylzinc to aromatic aldehydes has been studied. Enantioselectivities up to 76% have been obtained.     

手性氨基醇的合成及其在二乙基锌与芳香醛的不对称加成反应中的应用

以天然氨基酸为手性源,合成了3个新的三齿手性氨基醇配体(1a～1c),其结构经1H NMR, IR和元素分析表征.将1用于催化二乙基锌与芳香醛的不对称加成反应,得到(R)-二级醇,产率96.7%, e.e.74.3%.     

Enantioselective Addition of Diethylzinc to Benzaldehyde by Catalysts of Chiral Heterocyclic Ligands

TheenantioselectiveadditionofdiethylzincreagentstoprochiralcarbonylgrouphasbeenachievedprincipallybycatalyticalamountofchiralP-aminoalcoholswhichhaveproventobehighlyeffectivecatalysts'.Ahydroxylgrouphasbeenregardedtobenecessaryforthechiralligandtoformazincalkoxideasthecatalyticspecies'.Wewishtoreporthereinontheethylationofbenzaldehydewithdiethylzincpromotedbyseveralkindsofoxazolidineandthiazolidinederivativeswhichdonotcontainhydroxylgroup.Fourkindschiralheterocyclicligandsweusedarelistedasfoll…     

从脯氨酸合成一种三齿手性配体及其在二乙基锌对醛的对映选择性加成中的应用

A new chiral tridentate ligand [1-(1-methyl-S-pyrrolidin-2-ylmethyl)-S-pyrrolidin-2-yl]-diphenylmethanol (1) has been successfully synthesized from S-proline. The structure of the ligand was characterized by NMR spectra and X-ray diffraction analysis. Its catalytic ability has also been examined in enantioselective addition of diethylzinc towards aldehydes with 15%-84% enantiomeric excesses (ee).     

Synthesis of Novel 1,4‐Bissulfonamide Ligands for Enantioselective Addition of Diethylzinc to Aldehydes

Several novel chiral sulfonamide ligands based on (1R,2S,4R,5S)‐1,4‐diamino‐2,5‐dimethylcyclohexane skeleton have been synthesized and their application in the enantioselective addition of diethylzinc to aldehydes was investigated in the presence of Ti(OⁱPr)₄. The effect of ligands, temperature and the loading amount of ligands was studied. Under optimized conditions, enantioselective addition of diethylzinc with various aryl aldehydes and aliphatic aldehydes proceeded smoothly and afforded chiral secondary alcohols in up to 88% ee.     

A Novel Synthesis of Dimethyl Malonate by Carbonylation of Methyl Chloroacetate Catalyzed by Cobalt Complex

Dimethyl malonate (DMM) is an important organic synthesis intermediate. Traditional synthetic method by reaction of mono-chloroacetic acid with sodium cyanide1 is poisonous and complicated. Therefore, an interest in green synthesis routes of DMM has risen greatly. The several processes for preparing DMM by carbonylation of methyl chloroacetate catalyzed by Co2(CO)8 have been reported2~5. However, Co2(CO)8 is unstable and must be prepared under high pressure (12 Mpa). Moreover, the yield…     

手性β-氨基醇的合成及其催化二乙基锌与醛的不对称加成反应

以烯烃为原料通过Sharpless不对称双羟化等多步反应合成7种手性β-氨基醇, 并将该类化合物用于催化二乙基锌和醛的不对称加成反应. 分别考察了影响对映选择性的催化剂结构、催化剂用量、溶剂、反应温度等各种因素. 当催化剂用量为5%、甲苯溶剂、在－10 ℃下、以(1S,2R)-(＋)-2-氨基-1,2-二苯基乙醇(1b)作催化剂时, 所得仲醇的对映体过量最高为85% ee, 产率高达100%.     

联萘酚衍生C_3对称的手性配体的合成及其在诱导二乙基锌与芳基醛的不对称加成反应中的应用

合成了一种新型可重复使用的含手性联萘酚的C3对称树状小分子配体(L1),并将L1用于诱导二乙基锌和芳基醛的不对称加成反应.获得的二级醇最高的对映选择性为91%ee,产物最高收率达99%.反应完成后,只需经过简单的萃取和洗涤过程就可实现对配体L1高回收率的回收.配体L1重复使用5次其催化活性和对映选择性没有明显变化.     

Synthesis of Novel Chiral Diazole Derivative Ligands for the Enantioselective Addition of Diethylzinc to Benzaldehyde

The high-pressure-promoted reaction of epoxides with pyrazoles and imidazoles provided access to a variety of chiral diazole derivative ligands such as 11-23. Furthermore, chiral pyrazoles 26 and 27, which have a primary alcohol side chain, were also prepared from (+)-camphopyrazole 4. Each of these chiral diazole ligands was used for the catalytic enantioselective addition of diethylzinc to benzaldehyde. The best results were obtained for 16 and 18: 93% ee was achieved in both cases, and reversed asymmetric induction was observed. A plausible mechanism for this efficient asymmetric induction is offered on the basis of X-ray crystallographic data.     

Chiral tetrahedral complex catalyzing asymmetric addition of diethylzinc to benzaldehyde

The optical active alkyne-bridged Mo-Co heterometal complexes are synthesized by the chiral phase transfer catalyst (N-benzylcinchorin chloride) induced metal exchange reaction. The complex is used as catalyst to promote the asymmetric addition of diethylzinc to benzaldehyde. The ee value of the product alcohol is 5.7%, which illustrates the asymmetric induction of the tet-rahedral framework chirality in asymmetric catalysis reaction for the first time.     

新型手性膦配体的合成及其在 1,4-共轭加成反应中的应用

 以联萘酚和大位阻的金刚烷酰氯为原料, 经两步合成了系列新型手性单齿亚磷酸酯配体, 并应用于铜催化的二乙基锌对环烯酮的不对称 1,4-共轭加成反应. 结果表明, 产物收率和对映选择性最高分别为 95% 和 61%. 配体 (S)-(2-(adamantane- 1-carboxylic acid)-1,1’-binapthalen-2’-yl)-((S)-1,1’-binaphthalen-2,2’-yl)phosphite [(S,S)-3a]的两个 (S)-联萘酚构型是匹配的组合, 产物的绝对构型主要由配体中 2,2’-二氧膦-1,1’-联萘酚的构型控制.     

Enantioselective Alkynylation of Benzaldehyde Catalyzed by New Chiral Lewis Acid Ligand: Zinc-Amide Complex

The enantioselective alkynylzinc addition to aldehydes is very useful for the synthesis of chiral propargyl alcohols which are important versatile building blocks of many biologically active compounds and natural products1. A series of chiral oxazolidines were conveniently synthesized from amino acids in three steps with good yields. The use of chiral Lewis acid ligand: zinc-amide complex in situ generated from this oxazolidine with alkylzinc as chiral catalysts for the enantioselective alkyny…