双功能手性联萘酚配体在炔基锌对醛的不对称加成反应选择性能研究

单体2-溴吡啶, 2-溴-5-甲基吡啶, 2-氯-4-氟吡啶, 2-氯-3-三氟甲基吡啶分别与( R )-3,3′-二硼酸-2,2′-二甲氧基-1,1′-联萘 [( R )-2]在钯催化下, 通过Suzuki交叉耦合反应合成得到四个类似手性化合物( R )-3a-d。将它们应用到炔基锌对醛的不对称催化加成反应中,结果表明( R )-3a和( R )-3b的催化效果不好, 而( R )-3d只对脂肪醛有很好的催化效果,( R )-3c则对这类不对称催化反应均有很好的催化效果, 能给出高达95%的收率和99%的选择性结果。结果还表明所产生相应炔丙醇异构体构型为S,这与手性催化剂构型相反。     

Enantioselective Addition of Diethylzinc to Aromatic Aldehydes Using Chiral Oxazoline-Based Ligands

Russian Journal of Organic Chemistry - Chiral oxazoline ligands containing an aromatic ring were prepared from norephedrine and pyrrole-2-carbonitrile or 2-hydroxybenzoyl chloride. The synthesized...     

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．     

Synthesis of Chiral Pyridylphenols for the Enantioselective Addition of Diethylzinc to Aldehydes

Chiral 8‐substituted 2‐(8,10,10‐trimethyl‐6‐aza‐tricyclo[7.1.1.0^2,7]undeca‐2(7),3,5‐trien‐5‐yl)‐phenols were prepared from a high enantiopurity (>97% ee) of (1R)‐(+)‐α‐pinene, and assessed in the enantioselective addition of diethylzinc to substituted benzaldehydes, giving the (S)‐alcohols with enantiomeric excess ranging from 33% to 89%. Interestingly, in all cases, except for those of ortho‐chlorobenzaldehyde, ortho‐ and para‐methoxybenzaldehydes, the ee was >71%. The plot of the Hammett substitution constants vs. enantiomeric excess of the diethylzinc addition to either the ortho‐ or para‐substituted benzaldehydes shows a linear correlation.     

Peptide Deravatives as New Chiral Ligands for Enantioselective Phenylacetylene Addition to Aldehydes

The asymmetric addition of alkynylzinc to aldehydes is an important method of synthesizing chiral propargyl alcohols, which are important precursors to many chiral organic compounds. Recently, many significant chiral ligands in this area have been disclosed.[1] Use of a short peptide as a catalyst would allow expansion beyond the (still uncharted) repertoire of single amino acids, while conserving the advantages of a small molecule catalyst. To the best of our knowledge,no results of peptide derivatives as chiral ligands in this reaction has been disclosed to date.[2] Herein, we report the initial results of peptide derivatives, which have been used directly as a chiral ligand in this reaction (Scheme 1).     

Synthesis of Chiral Catalysts for the Enantioselective Addition of Diethylzinc to Aromatic Aldehydes

The reaction of diethylzinc with aromatic aldehydes and (S)-porretine derived catalysts was investigated. The synthesis of new chiral catalysts is also described.     

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.     

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…     

平面手性二茂铁N,O-配体催化苯乙炔对醛的不对称加成反应

 以手性N,N-二甲基二茂铁乙胺为原料,采用文献报道的方法合成了两个具有平面手性的二茂铁N,O-配体,并将其应用到苯乙炔对醛的不对称加成反应之中,考察了不同溶剂和不同底物的影响. 结果表明,配体(R)-1-[(α-二甲胺基)乙基]-(S)-2-(二苯基羟基甲基)二茂铁催化剂对该类反应具有较高的催化活性及较好的手性诱导能力,乙醚是该体系最好的溶剂,苯甲醛为底物时可获得高达82%的对映选择性.     

Enantioselective Addition of Diethylzinc to Aromatic Aldehydes Catalysed by Chiral Ligands Derived from L-Hydroxyproline

The Lithium salts of chiral auxiliaries 2–4 derived from L-Hydroxyprolin (2S, 4R)-1 catalysed the enantioselective addition of diethylzinc to aromatic aldehydes to afford sec alcohols in up to 80% optical purity.     

Syntheses and Crystal Structures of Chiral BINOL Derivatives and Their Applications in Enantioselective Lewis Acid Catalyzed Addition of Diethylzinc to Aldehydes

Two novel chiral BINOL derivatives with bis(benzylamine) groups at the 3,3- positions have been synthesized through the condensation reaction between 2,2'-bis(methoxy- methyleneoxy)-1,1'-binaphthyl-3,3'-dicarboxylic acid and benzylamine or N-phenyl benzylamine in the presence of triethylamine. Suitable single crystal of (R)-N,N'-dibenzyl-2,2'-dihydroxy-1, 1'-binaphthly-3,3'-diformamide (R)-3 for X-ray diffraction was obtained by recrystallization at room temperature from the mixture solvents. Crystallographic data of (R)-3: C40H36N2O6, Mr = 640.71, monoclinic, space group P21, a = 6.746(3), b = 21.883(9), c = 11.723(5) , β = 104.605(7)°, Z = 2, V = 1674.7(12) 3, Dc = 1.271 g/cm3, F(000) = 676, R = 0.0729, wR = 0.1687 and μ(MoKα) = 0.086 mm-1. Two chiral BINOL ligands were found to be effective in the enantioselective addition of diethylzinc to aldehydes and much different enantioselectivity was observed both in the presence and absence of Ti(OiPr)4. In the former case, (R)-3 showed moderate enantioselectivity, which was lower than that of (R)-BINOL's; and in the latter case, (R)-4 gave the highest enan- tioselectivity up to 93.3% ee.*     

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…     

手性联二萘酚衍生物催化芳香醛的不对称炔基锌加成反应

以手性联二萘酚为原料,合成了3,3’位取代的手性联二萘酚衍生物,研究了在该衍生物配体、二乙基锌和三乙胺条件下的苯乙炔对芳香醛的不对称加成反应,得到较好产率(43%～71%)的炔丙醇,ee值最高为68%。     

手性氨基二醇的合成及其在二乙基锌对醛不对称加成反应中的应用

手性配体催化的烷基锌试剂对醛的不对称加成反应是合成光学活性二级醇的重要方法 [1] ,1 0多年来 ,人们对其进行了深入的研究 ,并取得了很大进展 .其中大部分工作是设计如β-氨基醇等新的手性配体 .此外 ,文献 [2～ 6]还报道了氨基二醇在这类反应中具有手性诱导效果 .为进一步研究手性配体催化的二乙基锌对醛的不对称加成反应 ,我们合成了新的手性氨基二醇配体 ,并将其用于该反应中 .1　结果与讨论1 .1　手性配体的合成　以 L -脯氨酸甲酯盐酸盐 ( 5 )为原料 ,与溴代乙酸乙酯反应生成 ( L ) - N - ( 2 -乙酰乙氧基 )脯氨酸甲酯 ( 6)反应 ,…     

Diasteroselective Addition of Monoand Bis-Silylphosphines to Chiral Aldehydes

Abstract

The addition of silylphosphines to chiral aldehydes proceeds with high diastereoselectivity to give optically pure tertiary α -trimethylsiloxyalkylphosphines. The diastereomeric excesses of the addition products were achieved to 90–100%. The reaction of bis(trimethylsilyl)phenylphosphine with the acetonide of (R)-glyceraldehyde provides diastereomerically enriched tertiary bis(glyceryl)phosphines.     

Catalytic Enantioselective Addition of Alkylzirconium Reagents to Aliphatic Aldehydes

A catalytic methodology for the enantioselective addition of alkylzirconium reagents to aliphatic aldehydes is reported here. The versatile and readily accessible chiral Ph-BINMOL ligand, in the presence of Ti(OⁱPr)₄ and a zinc salt, facilitates the reaction, which proceeds under mild conditions and is compatible with functionalized nucleophiles. The alkylzirconium reagents are conveniently generated in situ by hydrozirconation of alkenes with the Schwartz reagent. This work is a continuation of our previous work on aromatic aldehydes.     

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 Chiral Aminophenols Based on Proline and Their Application in Enantioselective Addition of Diethylzinc to Aldehydes

Three 2-{（3R, 7aS )-1, 1-disubstituted-tetrahydro-lH-pyrrolo [ 1,2- c ] [ 1,3 ] oxazol-3-yl} phenols have been synthesized from salicylaldehyde and amino alcohols derived from L-proline, and used as ligands in enantioselective addition of diethylzinc to aldehydes, the ee values of obtained secondary alcohols were found in the range of 0-90%.