共查询到19条相似文献,搜索用时 152 毫秒
1.
2.
简要介绍了多齿胺膦金属配合物的设计合成。这些多齿配合显示了单齿胺或膦金属配合物所不具有的丰富结构类型和特殊催化性质,合成和表征了含有结构类似的双亚胺双膦钌配合物(R,R)-3和双胺双膦钌配合物(R,R)-4。配合物(R,R)-4可作为多种芳香酮不对称氢化的手性催化剂,其光学收率最高达97%。讨论了钌配合物的催化作用机理。 相似文献
3.
采用溴化钯为催化剂前体,与非螯合型双齿膦配体L1(DPPFF)、联吡啶型双齿膦配体L2(P-PHOS)和二茂铁基手性双膦配体L3((S,Rp)-BPPF)制备络合物催化剂,以乙酰丙酮羰基铑为催化剂前体,与手性亚磷酸酯配体L4-L6制备络合物催化剂,将其分别应用于底物环己基甲醛或苯乙醛的不对称酰胺羰化反应中,研究结果表明... 相似文献
4.
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
5.
新型手性膦-硼烷配合物的合成及其在不对称催化氢化反应中的应用 总被引:2,自引:0,他引:2
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,经酯化、亲核取代反应转化为手性膦-硼烷配合物.后者克服了有机膦配体易氧化的缺点,其制备过程简单,易于提纯,在空气中可长期保存.该手性膦-硼烷配合物在四氟硼酸-甲醚的存在下解络,生成的自由膦不经分离直接与[Rh(COD)Cl]2作用生成手性膦-铑原位催化剂.在α-乙酰氨基肉桂酸甲酯的不对称氢化反应中,转化率为100%,对映选择性88%e.e. 相似文献
6.
7.
8.
合成了四个从葡萄糖及半乳糖衍生的手性芳基双膦配体,制备了手性双膦-铑(Ⅰ)配合物催化剂,并将其用于苯乙烯不对称氢甲酰化反应中.结果表明,葡萄糖骨架手性中心与联萘基之间有协同作用,对映体过量值和转化率受配体C-4骨架立体中心的绝对构型影响,而产物的绝对构型则主要由联萘单元控制;配体4-双{[(S)-1,1′-联萘基-2,2′-双基]-磷}-苯基-3,6-脱水-β-D-葡萄糖的吡喃糖苷基和联萘基的匹配组合,给出41%的对映体选择性和74∶26(异构/正构)区域选择性. 相似文献
9.
正手性过渡金属配合物催化的不对称氢化是合成手性药物、农药和精细化工中间体的重要方法.到目前为止,已经有一些过渡金属/配体配合物催化的不对称氢化反应得到工业化应用,典型的实例如孟山都公司采用手性双齿膦配体DIPAMP生产L 相似文献
10.
11.
12.
Jian-shan Chen 《Tetrahedron letters》2004,45(45):8415-8418
The chiral Ir catalytic system generated in situ from iridium hydride complex and chiral diaminodiphosphine ligand was employed in asymmetric transfer hydrogenation of aromatic ketones to give the corresponding optically active alcohols, with up to 99% ee in high yield were obtained even when the substrate-to-catalyst molar ratio reached 10000:1. 相似文献
13.
Takao Ikariya Hui Wang Masahito Watanabe Kunihiko Murata 《Journal of organometallic chemistry》2004,689(8):1377-1381
Well-defined 16-electron chiral Ru amido complexes, Ru[(R,R)-diamine](η6-arene), efficiently catalyze asymmetric Michael additions of Michael donors to cyclic enones to give adducts in high yields and with excellent ee’s. β-Ketoesters or nitroacetate as Michael donors react with 2-cyclopentenone in toluene or t-butyl alcohol containing the Ru amido catalyst (S/C=50) to afford the Michael adduct in 99% yield and with up to 92% ee. The outcome of the reaction was delicately influenced by the structures of the diamine and arene ligands as well as reaction conditions. 相似文献
14.
手性羰基铁络合物很少被用于芳香酮的不对称氢转移氢化.利用不同的羰基铁络合物与手性双胺双膦配体现场络合,形成手性胺膦铁催化体系.考察了它们对多种芳香酮的不对称氢转移催化氢化性能.结果表明,三核的手性胺膦铁簇合物是催化芳香酮不对称氢转移氢化的较好体系.当用三核的铁簇合物[Et3NH]+[HFe3(CO)11]-体系催化1,1-二苯基丙酮的氢化时,最高可获得98%的对映选择性.通过现场红外光谱测定,揣测羰基铁簇合物Fe3(CO)12在催化反应过程中保持三核的簇合物的簇骼不变. 相似文献
15.
Cornejo A Fraile JM García JI Gil MJ Luis SV Martínez-Merino V Mayoral JA 《The Journal of organic chemistry》2005,70(14):5536-5544
[reaction: see text] Flexible and versatile methods have been developed for the immobilization of chiral pyridinebis(oxazoline) ligands by covalent bonding to a solid support, either by grafting or by polymerization. Different spacers can easily be introduced to modulate the support-ligand distance and the electronic properties of the chiral ligand. As an example, 2,6-bis[(S)-4-isopropyloxazolin-2-yl]pyridine has been immobilized on polystyrene resins, both on a Merrifield-type resin by grafting and on supports prepared by polymerization of 4-vinyl-substituted ligands. The corresponding Ru complexes have been tested as catalysts in the cyclopropanation reaction between styrene and ethyl diazoacetate. The catalytic activity, the enantioselectivity, and the recyclability are strongly dependent on the catalyst preparation method and the total exclusion of oxygen and moisture in the filtration process. Under such optimized conditions, yields over 60% with up to 90% ee can be obtained in four successive reactions-the best cyclopropanation results described to date for a chiral solid ruthenium catalyst. 相似文献
16.
The highly enantioselective hydrogenation of methyl 4-tert-butylcarbamoyl-3-oxo-butyrate to the corresponding secondary alcohol, representing an interesting chiral building block, for example, for the synthesis of statins, has been investigated in the presence of homogeneous chiral Rh(I) and Ru(II) complexes bearing phosphine ligands. The highest enantioselectivity (up to 96%) was achieved with a [Ru((R)-BINAP)(p-cymene)Cl]Cl complex (sub./cat. ratio 100:1, 5 bar H2, rt, MeOH). 相似文献
17.
Nermin Meriç Cezmi Kayan Nevin Gürbüz Mehmet Karakaplan Nil Ertekin Binbay Murat Aydemir 《Tetrahedron: Asymmetry》2017,28(12):1739-1749
Metal-catalyzed asymmetric transfer hydrogenation is a powerful and practical method for the reduction of ketones to produce the corresponding secondary alcohols, which are valuable building blocks in the pharmaceutical, perfume, and agrochemical industries. Hence, a series of novel chiral β-amino alcohols were synthesized by chiral amines with regioselective ring opening of (S)-propylene oxide or reaction with (S)-(+)-2-hydroxypropyl p-toluenesulfonate by a straightforward method. The chiral ruthenium catalytic systems generated from [Ru(arene)(μ-Cl)Cl]2 complexes and chiral phosphinite ligands based on amino alcohol derivatives were employed in asymmetric transfer hydrogenation of ketones to give the corresponding optically active alcohols; (2S)-1-{[(2S)-2-[(diphenylphosphanyl)oxy]propyl][(1R)-1-phenylethyl]amino}propan-2-yldiphenylphosphinitobis[dichol-oro(η6-benzene)ruthenium(II)] acts an excellent catalyst in the reduction of α-naphthyl methyl ketone, giving the corresponding alcohol with up to 99% ee. The substituents on the backbone of the ligands were found to have a remarkable effect on both the conversion and enantioselectivity of the catalysts. Furthermore, this transfer hydrogenation is characterized by low reversibility under these conditions. 相似文献
18.
Zhang H Yang CB Li YY Donga ZR Gao JX Nakamura H Murata K Ikariya T 《Chemical communications (Cambridge, England)》2003,(1):142-143
The chiral Ru cluster-based catalyst systems generated in situ from Ru3(CO)12 and chiral diiminodiphosphine tetradentate ligands effected asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in 94% yield and with 96% ee. 相似文献
19.
Baratta W Ballico M Baldino S Chelucci G Herdtweck E Siega K Magnolia S Rigo P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(30):9148-9160
New benzo[h]quinoline ligands (HCN'N) containing a CHRNH2 (R=H (a), Me (b), tBu (c)) function in the 2-position were prepared starting from benzo[h]quinoline N-oxide (in the case of ligand a) and 2-chlorobenzo[h]quinoline (for ligands b and c). These compounds were used to prepare ruthenium and osmium complexes, which are excellent catalysts for the transfer hydrogenation (TH) of ketones. The reaction of a with [RuCl2(PPh3)3] in 2-propanol at reflux afforded the terdentate CN'N complex [RuCl(CN'N)(PPh3)2] (1), whereas the complexes [RuCl(CN'N)(dppb)] (2-4; dppb=Ph2P(CH2)4PPh2) were obtained from [RuCl2(PPh3)(dppb)] with a-c, respectively. Employment of (R,S)-Josiphos, (S,R)-Josiphos*, (S,S)-Skewphos, and (S)-MeO-Biphep in combination with [RuCl2(PPh3)3] and ligand a gave the chiral derivatives [RuCl(CN'N)(PP)] (5-8). The osmium complex [OsCl(CN'N)(dppb)] (12) was prepared by treatment of [OsCl2(PPh3)3] with dppb and ligand a. Reaction of the chloride 2 and 12 with NaOiPr in 2-propanol/toluene afforded the hydride complexes [MH(CN'N)(dppb)] (M=Ru 10, Os 14), through elimination of acetone from [M(OiPr)(CN'N)(dppb)] (M=Ru 9, Os 13). The species 9 and 13 easily reacted with 4,4'-difluorobenzophenone, via 10 and 14, respectively, affording the corresponding isolable alkoxides [M(OR)(CN'N)(dppb)] (M=Ru 11, Os 15). The complexes [MX(CN'N)(P2)] (1-15) (M=Ru, Os; X=Cl, H, OR; P=PPh3 and P2=diphosphane) are efficient catalysts for the TH of carbonyl compounds with 2-propanol in the presence of NaOiPr (2 mol %). Turnover frequency (TOF) values up to 1.8x10(6) h(-1) have been achieved using 0.02-0.001 mol % of catalyst. Much the same activity has been observed for the Ru--Cl, --H, --OR, and the Os--Cl derivatives, whereas the Os--H and Os--OR derivatives display significantly lower activity on account of their high oxygen sensitivity. The chiral Ru complexes 5-8 catalyze the asymmetric TH of methyl-aryl ketones with TOF approximately 10(5) h(-1) at 60 degrees C, up to 97 % enatiomeric excess (ee) and remarkably high productivity (0.005 mol % catalyst loading). High catalytic activity (TOF up to 2.2x10(5) h(-1)) and enantioselectivity (up to 98 % ee) have also been achieved with the in-situ-generated catalysts prepared from [MCl2(PPh3)3], (S,R)-Josiphos or (S,R)-Josiphos*, and the benzo[h]quinoline ligands a-c. 相似文献