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《催化学报》2015,(8)
喹啉不对称氢化反应是不对称氢化研究的重点之一.其氢化产物四氢喹啉不仅是重要的有机合成中间体,同时也是自然界中生物碱的结构单元和生物活性化合物.周永贵研究组首次报道了手性(R)-MeO-Biphep/Ir体系成功用于喹啉的不对称催化,取得了非常好的反应结果.随后他们对喹啉底物进行了拓展,包括拥有特殊取代基的喹啉衍生物,均取得了良好的反应结果.后来多个研究组对该反应进行了深入研究并开发出了多个不同手性膦配体的Ir催化体系.虽然喹啉不对称氢化反应取得了很大的发展,但是该均相反应体系只能在高的反应催化剂用量下才能实现好的结果.进一步研究发现手性配体与金属Ir络合后形成反应活性物种,但后者可发生二聚或三聚,生成的产物是不具有催化活性的,从而导致了反应体系需要高的催化剂的用量.为此人们做了大量研究.范青华研究组通过对BINAP基团上嫁接大空间位阻的枝状分子合成了一系列新的手性BINAP配体,在与Ir络合后,表现出远高于均相催化剂的反应活性,且可循环利用.在该体系中,大位阻的枝状分子起到了阻隔活性物种二聚、三聚的作用,因而提高了反应活性.后来周永贵研究组也尝试通过改变有机配体的方法来实现高的反应活性.他们选择改变手性双膦配体上P原子所连接有机配体的空间位阻来实现对活性物种多聚的控制.实验同样取得了很好的反应效果.对于均相反应体系,我们只能通过这种改变有机配体空间位阻的方式来降低活性物种多聚的可能性,那么如何彻底阻止这种多聚呢?非均相体系给我们提供了很好的研究思路,但如何将非均相体系引入到喹啉不对称氢化反应体系当中成为了难点.共轭微孔聚合物(CMPs)的发展使得手性催化体系很容易从均相转变到非均相.这种材料具有较高的比表面积和固定的开放孔道结构,可应用于非均相催化中.且制备相对容易.我们可以将手性双膦配体作为材料制备配体嫁接到CMPs材料当中.在这种材料当中,手性配体会以有序、空间分离的方式分布,在与Ir配合后应用于喹啉不对称氢化反应中,从而从根本上避免了活性物种多聚的可能因此反应活性提高.我们曾首次成功合成了一系列含有手性(R)-Binap基团的共轭微孔聚合材料-BINAP-CMPs,并将其用于β-酮酸酯的不对称氢化反应当中,取得了很好的催化效果.手性BINAP基团均匀、有序地分散于该材料中.我们尝试利用BINAP-CMPs固有的空间隔离效应,将其应用于喹啉的不对称氢化反应中,结果表明,在相同条件下,非均相BINAP-CMPs/Ir催化体系的TOF值是340 h–1,是均相BINAP/Ir体系(100 h–1)3倍,反应的对映体选择性与均相相当;另外该催化体系多循环利用次后仍可以保持高的反应活性.我们还发现材料结构性质对反应结果的影响很大,材料的比表面积和孔容更大反应结果更好. 相似文献
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Chiral S,P-donor ferrocene-derived ligands were synthesized and applied in the asymmetric hydrogenation of quinolines using the [Ir(COD)Cl]2/S,P-ligand complex as the catalyst in the presence of iodine. The effects of the solvent and hydrogen pressure on conversion and enantioselectivity were examined, and up to 82% ee was obtained. The planar chirality plays an important role in this reaction. R- and S-enantiomers of 1,2,3,4-tetrahydroquinoline derivatives were obtained using ligands 3 and 5, respectively. 相似文献
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手性茂金属催化剂在不对称硅氢化反应中的应用 总被引:2,自引:0,他引:2
手性茂金属催化剂在不对称硅氢化反应中的应用研究近扯为取得了很大进展。对90年代以来具有高手性诱导效应的手性二茂铁络合催化剂及手性二茂钛系催化剂进行了重点评述,并展望了其应用研究前景。 相似文献
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以8-喹啉羧酸为原料,通过8-喹啉酰氯与手性氨基醇反应或8-喹啉羧酸乙酯与氨基醇的酯交换反应制得酰胺6a-c,再经Ni-Al合金催化还原、甲磺酸催化脱水关环,合成了新型手性氢化喹啉唑啉配体2a-c.在苯乙酮的不对称催化氢转移反应的初步研究中,使用2C与RuCl2(Cymene)]2形成的手性催化剂得到71%产率和44%的e.e值. 相似文献
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非螯合型手性双膦/钌催化的不对称氢化反应 总被引:1,自引:0,他引:1
对RuCl3和手性双膦(2S,5S)-2,5-双-(二苯膦)-1,4∶3,6-双脱水-2,5-双去氧-L-艾杜醇(BDPI)催化的不对称氢化反应进行了研究,反应的转化率为100%,光学收率受[双膦]/[RuCl3]比值的影响较大.在α-乙酰胺基肉桂酸的催化氢化反应中,[双膦]/[RuCl3]=2.0时e.e.值最大,为68%;对衣糠酸的催化氢化,[双膦]/[RuCl3]=3时e.e.值最大,为92%. 相似文献
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<正>手性醇是一类非常重要的手性化合物,它是合成手性药物、天然产物等的重要中间体。酮的不对称催化氢化反应是合成手性醇的最为经济且环境友好的方法之一,目前已经发展了很多用于酮的不对称氢化反应的手性催化剂,但是,真正高效的手性催化剂还很少。我们在研究酮的不对称催化氢化反应过程中,发现手 相似文献
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An efficient method for the transfer hydrogenation of quinolines catalyzed by a Cp∗Ir complex was developed. A variety of 1,2,3,4-tetrahydroquinolines were obtained by regio- and chemoselective transfer hydrogenation of quinolines using 2-propanol as a hydrogen source. 相似文献
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Esa Toukoniitty Päivi Mäki-Arvelaa Rainer Sjöholm Reko Leino Tapio Salmi Dmitry Yu. Murzin 《Reaction Kinetics and Catalysis Letters》2002,75(1):21-30
Three different modifiers, (-)-cinchonidine, 10,11-dihydrocinchonidine and (+)-cinchonine were investigated in the enantioselective hydrogenation of an unsymmetrical dione, 1-phenyl-1,2-propanedione, over a commercial Pt/Al2O3 catalyst. The catalytic activity, as well as the regio- and enantioselectivity in the hydroxyketones and diols formed were compared. 相似文献
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Nevin Arslan 《Phosphorus, sulfur, and silicon and the related elements》2020,195(8):628-637
AbstractThe interaction of [Ru(η6-arene)(μ-Cl)Cl]2 and Ir(η5-C5Me5)(μ-Cl)Cl]2 with a new Ionic Liquid-based phosphinite ligand, [(Ph2PO)-C6H9N2Ph]Cl, (2) gave [Ru((Ph2PO)-C6H9N2Ph)(η6-p-cymene)Cl2]Cl (3), [Ru((Ph2PO)-C6H9N2Ph)(benzene)Cl2]Cl (4) and [Ir((Ph2PO)-C6H9N2Ph)(C5Me5)Cl2]Cl (5), complexes. All the compounds were characterized by a combination of multinuclear NMR and IR spectroscopy as well as elemental analysis. Furthermore, the Ru(II) and Ir(III) catalysts were applied to asymmetric transfer hydrogenation of acetophenone derivatives using 2-propanol as a hydrogen source. The results showed that the corresponding alcohols could be obtained with good activity (up to 55% ee and 99% conversion) under mild conditions. Notably, [Ir((Ph2PO)-C6H9N2Ph)(C5Me5)Cl2]Cl (5) is more active than the other analogous complexes in the transfer hydrogenation (up to 81% ee). 相似文献
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A highly enantioselective synthesis of optically active N-tosyl-4-alkyl-1,3-oxazolidin-2-ones based on the asymmetric hydrogenation of the trisubstituted exocyclic double bond of N-tosyl-4-alkylidene-1,3-oxazolidin-2-ones under the catalysis of neutral [Rh(COD)Cl]2 (COD=1,5-cyclooctadiene) and (S)-(+)-DTBM-SEGPHOS was developed. The utility of this highly enantioselective reaction was exemplified by the synthesis of optically active amino acids, amino alcohols, and piperidine derivatives. 相似文献
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Enantioselective hydrogenation of quinolines catalyzed by Ir(BINAP)-cored dendrimers: dramatic enhancement of catalytic activity 总被引:1,自引:0,他引:1
[structure: see text]. The asymmetric hydrogenation of quinolines catalyzed by chiral dendritic catalysts derived from BINAP gave the corresponding products with high enantioselectivities (up to 93%), excellent catalytic activities (TOF up to 3450 h(-1)), and productivities (TON up to 43,000). In addition, the third-generation catalyst could be recovered by precipitation and filtration and reused at least six times with similar enantioselectivity. 相似文献
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Szabolcs Cserényi Imre Bucsi Károly Felf?ldi 《Reaction Kinetics and Catalysis Letters》2006,87(2):395-403
Summary The enantioselective hydrogenation of ethyl pyruvate (EtPy) was studied on Pt-alumina catalysts modified by C3-substituted
cinchonidines (NC, A, B, C1, C2in Fig. 1) and for comparison by DHCDand MeO-DHCDin AcOH. The effect of the C3-substituent on the reaction rate and the enantioselectivity were examined. Using the Engelhard
4759 catalyst under mild experimental conditions (room temperature, hydrogen pressure 1 bar) such as DHCDthe (R)-ethyl lactate formed in excess (e.e.max: 79-91%)</o:p> 相似文献
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Eddy Maerten Francine Agbossou-Niedercorn Yves Castanet André Mortreux 《Tetrahedron》2008,64(37):8700-8708
Ruthenium-diamine-diphosphine complexes provide highly efficient catalysts for enantioselective hydrogenation of a series of pyridinyl aryl ketones. The hydrogenation proceeds under mild conditions providing chiral pyridinyl aryl methanol derivatives with consistently high yields and moderate to excellent enantioselectivities (up to 99% ee) according to the structure of the chiral diphosphine. NMR studies, based on Mosher's ester derivatisation, allowed to determine the configuration of the major alcohol obtained during asymmetric hydrogenation. 相似文献
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Summary A new gas chromatographic method for the simultaneous determination of the degree of hydrogenation of ketopantolactone and the enantiomeric excess of pantolactone does not require any derivatisation.
Bestimmung von Enantiomerenüberschuß und Hydriergrad bei der enantioselektiven Hydrierung von Ketopantolacton (Kurze Mitt.)
Zusammenfassung Zur Bestimmung des Hydriergrads von Ketopantolacton und des Enantiomerenüberschusses von Pantolacton wird ein neues gaschromatographisches Verfahren eingesetzt, das keine Derivatisierung erfordert.相似文献
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The asymmetric transfer hydrogenation of activated olefins with chiral ruthenium amido complexes (Noyori catalyst) using formic acid-triethylamine azeotrope as hydrogen source resulted in excellent yields and high enantioselectivities (up to 88.5%). 相似文献