首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
新型手性配体的设计合成是不对称催化研究的重要内容,其中手性胺膦配体因同时含有"软"的磷原子和"硬"的氮原子而具有丰富的配位化学性能和优秀的不对称诱导能力.本文总结了本研究组最近设计合成的手性环状胺膦配体的制备、表征及其在铁催化酮的不对称还原中的应用.手性1,2-环己二胺与双(2-甲酰基苯基)苯基膦通过[2+2]环缩合反应能够顺利获得手性22元环的亚胺膦配体21,该配体经Na BH4还原后生成大环胺膦配体22.利用手性大环胺膦配体22与Fe3(CO)12原位生成的催化体系,能够高活性、高对映选择性地实现包括杂环芳香酮在内50多种酮的不对称转移氢化和不对称氢化反应,其S/C(底物与催化剂的摩尔比)最高可达5000:1,产物手性芳香醇的光学纯度高达99%ee.  相似文献   

2.
手性膦小分子催化的不对称反应是目前研究的热点之一,该类反应具有反应时间短、条件温和、催化活性高、环境友好等优点,符合绿色化学发展方向.对手性膦小分子催化的不对称Morita-Baylis-Hillman反应、Morita-Baylis-Hillman加成物的烯丙基位立体选择性取代反应、环加成反应、酯化反应,γ-加成反应以及其它重要的不对称反应进行简要的评述.  相似文献   

3.
手性膦配体的合成及其在不对称催化反应中的应用一直是不对称有机合成和催 化研究中非常重要的研究领域,大量的单齿、双齿和多齿磷配体被合成出来并成功 地应用于不对称催化研究。综述了近十几年来手性磷配体的研究进展。  相似文献   

4.
非螯合型手性双膦在苯乙烯的不对称催化氢甲酰化中的应用吕士杰,成克军,周宏英,郑燕,傅宏祥(中国科学院兰州化学物理研究所羰基合成和选择氧化国家重点实验室,兰州730000)黄梁仁(中国科学院福建物质结构研究所,福州350002)关键词手性双膦,不对称氢...  相似文献   

5.
手性二茂金属膦配体在不对称合成中的应用及新进展   总被引:1,自引:0,他引:1  
牟宗刚  吕士杰 《分子催化》1996,10(2):149-159
手性二茂金属膦配体在不对称合成中的应用及新进展牟宗刚,吕士杰,周宏英,傅宏祥(中国科学院兰州化学物理研究所兰州730000)关键词二茂铁膦配体,烯丙基化合物,二茂钌膦配体,不对称合成,不对称催化,均相催化1前言众所周知,催化作用的研究已成为近代化学的...  相似文献   

6.
徐小红  吕士杰 《分子催化》1996,10(5):391-399
手性膦配体及其不对称催化的研究进展①徐小红吕士杰傅宏祥(中国科学院兰州化学物理研究所,兰州730000)关键词膦配体手性配体不对称催化1前言手性是宇宙间的普遍特性,在生命的产生和演变过程中,自然界往往对一种手性有所偏爱.如:自然界存在的糖为D构型,氨...  相似文献   

7.
利用邻二苯基膦苯甲醛分别与多种手性二胺的缩合反应,设计合成了一系列新型手性四齿胺膦配体.这类多齿胺膦配体含有两个软的磷原子和两个硬的氮原子,具有丰富的配位化学性能和优秀的不对称诱导能力.本文综述了手性胺膦金属络合物催化剂在不对称转移氢化反应、氧化动力学拆分反应、烯烃的不对称环氧化反应和不对称环丙烷化反应、不对称D-A反应中的应用.  相似文献   

8.
李晓东  陈新滋 《分子催化》2000,14(6):401-408
近年来 ,随着人们对手性对映异构体在生物活性上存在巨大差异认识的提高 ,使对手性纯化学品的市场需求大大增加 ,尤其表现在药物、农用化学品、食品添加剂及香料等领域 [1~ 6] .作为获得手性纯物质的重要途径 ,不对称催化反应在众多不对称合成反应中是最有效的 ,也最具有经济开发价值 ,因而成为当前有机合成和催化的一个前沿研究领域 [7~ 8] .其中 ,不对称氢化是不对称催化反应在工业生产上的首例应用 ,也是目前研究最深入、最广泛的不对称催化题目之一[9] .1 968年 ,Horner[10 ] 和Knowles[11]等将手性膦配体引入 Osborn等 [12 ]的均相…  相似文献   

9.
研究了Pincer-钯催化的甲基苯基膦氢对卤代烃的不对称取代反应.以高收率、中等的立体选择性得到含膦手性中心的膦化合物,同时对反应的催化循环和可能的立体化学过程进行了探讨.  相似文献   

10.
以苯乙烯为原料,通过Sharpless不对称二羟基化反应合成高对映体纯的苯基乙二醇,经环化、亲核开环和取代反应转化为手性碳膦-氧膦型双膦配体.后者与[Rh(COD)Cl]2及NH4PF6作用生成手性膦-铑阳离子催化剂.在α-脱氢氨基酸衍生物的不对称氢化反应中,化学转化率为100%,对映选择性最高达到77?.  相似文献   

11.
This article describes efficient preparation of isomeric allyl phosphine oxides possessing a protected cyclohexanediol fragment. Their base-catalyzed interconversions are examined and reactions with the Grundmann ketone provide an adduct containing the rearranged vinyl phosphine oxide moiety, instead of 19-norvitamin D3 analogs, the expected products of the Horner–Wittig process.  相似文献   

12.
三辛基氧化膦(TOPO)萃取铟的研究   总被引:2,自引:0,他引:2  
本文研究了三辛基氧化膦(TOPO)自盐酸溶液中萃取铟的性能,其萃取率是随酸度的增加而增加。与P_(350)和TBP相比较,萃取能力大小顺序为:TOPO>P_(350)>TBP经斜率法和化学分析法研究确定,TOPO白盐酸溶液中萃取铟的反应为:In_((a))~(3+)+H_((a))~++4Cl_((a))~-+2TOPO_((o))F(?)HInCl_4·2TOPO_((o))IR和NMR研究证明:铟是以H[InCl_4]形式被萃入TOPO有机相中的。  相似文献   

13.
Extensive DFT calculations provide detailed mechanistic insights into the metal-free reduction of phosphine oxide Ph3P=O by using chlorination reagents O=CClX (X=COCl, Cl, OCCl3 and Ph) and H2. Fast electrophilic attack to the P=O group oxygen atom is favored by exergonic CO2 release to form phosphonium Ph3PCl+ and chloride Cl, which may slowly cleave H2 by an unstable HPh3PCl complex yielding Ph3PH+ and Cl ions in solution. Moderate heating is required to accelerate the slow H2-activation step and to eliminate HCl to form phosphine Ph3P instead of Ph3PH+Cl salt as the desired product. Though partially quenched by Ph3P (and reactant Ph3P=O if present), borane B(2,6-F2C6H3)3 can be still combined with Cl and Ph3P as reactive frustrated Lewis pair (FLP) catalysts.  相似文献   

14.
The crystal structure of the title compound, C26H27O6P, has been determined by single-crystal X-ray diffraction analysis. The crystal is orthorhombic with space group P212121, a=6.154(4), b=17.199(8), c=22.180(3)(A), V=2347.6(A)3, Dc=1.32 g/cm3, F(000)=984, μ=1.5cm-1, Z=4, and final R=0.075 and Rw=0.080 for 1417 reflections (I≥3σ(I)). The X-ray diffraction analysis revealed that the structure of the title compound s similar to that of its parent phosphine and the pyranose and 4, 6-O-benzylidene rings remain distorted chair conformations.  相似文献   

15.
A new rhodium complex with a nitrogen‐containing bis(phosphine oxide) ligand has been synthesized. The complex was applied to hydroformylation of styrene and displayed high activity and regioselectivity towards the branched aldehyde, which was found to be higher than those of the tertiary bis(phosphine) analogue. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

16.
Reaction of sodium diallylisocyanurate with tris(chloromethyl)-, bis(chloromethyl)phenyl-, and (chloromethyl)diphenylphosphine oxides yields, depending on the stoichiometric ratio of the reagents, mono-, bis-, and tris(3,5-diallylisocyanuratomethyl)phosphine oxides.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan, Tatarstan, Russia. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2773–2777, December, 1992.  相似文献   

17.
DFT studies on several dppf ‐ and dppc ‐derived bidentate phosphines ligated palladium complexes catalyzed Suzuki‐Miyaura coupling reactions were pursued. The catalytic reactions employing ligands, having two phosphine biting sites on different cyclpentadienyl or cyclobutadiene rings, such as 1,1'‐dmpf or 1,1' ‐dmpc, have been verified to be energetically more favorable than those on the same ring provided that tetra‐coordinated palladium conformations for all transition states and intermediates are maintained. Apart from the purpose of storage, the application of phosphinous acid (R2P(OH)) in Suzuki‐Miyaura reaction is inferior to tertiary phosphine (R3P).  相似文献   

18.
Rhodium-catalyzed hydroformylation of 1-octene in the presence of different phosphine and phosphine oxide ligands has been investigated. The molecular structure of new phosphine ligand, fluorenylidine methyl phenyl diphenylphosphine, was determined by single-crystal X-ray crystallography. Parameters such as different ligands, molar ratio of ligand to rhodium complex, ratio of olefin to rhodium complex, pressure of CO : H2 mixture, and time of the reaction were studied. The linear aldehyde was the main product when the phosphine ligands were used as auxiliary ligands while the selectivity was changed to the branched products when the related phosphine oxide ligands were used. Under optimized reaction conditions, in the presence of [Rh(acac)(CO)(Ph3P)]-di(1-naphthyl)phenyl phosphine oxide, conversion of 1-octene reached 97% with 87% selectivity of branched aldehyde.  相似文献   

19.
DFT studies on several dppf ‐ and dppc ‐derived bidentate phosphines ligated palladium complexes catalyzed Suzuki‐Miyaura coupling reactions were pursued. The catalytic reactions employing ligands, having two phosphine biting sites on different cyclpentadienyl or cyclobutadiene rings, such as 1,1′‐dmpf or 1,1′‐dmpc , have been verified to be energetically more favorable than those on the same ring provided that tetra‐coordinated palladium conformations for all transition states and intermediates are maintained. Apart from the purpose of storage, the application of phosphinous acid (R2P(OH)) in Suzuki‐Miyaura reaction is inferior to tertiary phosphine (R3P).  相似文献   

20.
A novel diamine, bis(3‐aminophenyl)‐4‐(1‐adamantyl)phenoxyphenyl phosphine oxide (mDAATPPO), was synthesized via the Williamson ether reaction of 4‐(1‐adamantyl)phenol and bis(3‐nitrophenyl)‐4‐fluorophenyl phosphine oxide, followed by reduction. The phenol group was prepared by the Friedel–Crafts reaction of 1‐bromoadamantane and phenol, whereas the phosphine oxide group was synthesized by the Grignard reaction of 1‐bromo‐4‐fluorobezene and diphenyl phosphinic chloride, followed by nitration. The monomer and its intermediate compounds were characterized with Fourier transform infrared, NMR, and melting‐point apparatus. The monomer was then used to prepare polyimides with 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride, 4,4′‐oxydiphthalic dianhydride, and pyromellitic dianhydride by the conventional two‐step synthesis: the preparation of poly(amic acid) followed by solution imidization. The molecular weights of the polyimides were controlled to 20,000 g/mol by off‐stoichiometry, and the synthesized polyimides were characterized with Fourier transform infrared, NMR, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. In addition, the solubility, intrinsic viscosity, dielectric constant, and birefringence of the polyimides were evaluated. Novel polyimides with mDAATPPO exhibited good solubility, high glass‐transition temperatures (290–330 °C), excellent thermal stability (>500 °C), low dielectric constants (2.77–3.01), low refractive indices, and low birefringence values (0.0019–0.0030). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2567–2578, 2006  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号