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New phosphine-diamine and phosphine-amino-alcohol tridentate ligands for ruthenium catalysed enantioselective hydrogenation of ketones and a concise lactone synthesis enabled by asymmetric reduction of cyano-ketones
José A Fuentes, Scott D Phillips, Matthew L Clarke
Chemistry Central Journal , 2012, DOI: 10.1186/1752-153x-6-151
Abstract: Reduction of C = O and C = N double bonds using molecular hydrogen is a very important process, due to its low cost and complete atom efficiency [1]. Homogeneous hydrogenation of unfunctionalised ketones could not be carried out with sufficient efficiency or chemo-selectivity until the Noyori group’s pioneering research on ruthenium complexes containing both diphosphine and diamine ligands (e.g. 1 and 2, Scheme?1) [2,3]. These catalysts give excellent results in the hydrogenation of a range of acetophenone derivatives, as have a number of structurally related catalysts [4,5]. However, [RuCl2(BINAP)(DAIPEN)] and related catalysts do have some important limitations, that have spurred significant interest in new catalyst development [6-21]. Given that so many drugs, agrochemicals, materials, and natural products can be disconnected back to enantiopure secondary alcohols, it is of significant importance to extend asymmetric hydrogenation chemistry such that it is effective for every major class of substrate. We have already reported on the reduction of some of these challenging substrates, namely bulky ketones [6,10,11], heterocycle appended (bulky) ketones [10], and certain esters [9]. To achieve this, we developed ruthenium complexes of chiral tridentate P,N,N and P,N,OH ligands (derived from cyclohexane diamine and aminocyclohexanol). These gave moderate to excellent enantioselectivity and high yields where there was a precedent for [RuCl2(BINAP)(DAIPEN)] giving very low yields. However, while these results are significant in developing P,N,N ligands for catalytic hydrogenation reactions, further improvements are needed for the catalysts to become industrially useful. In this paper, we report investigations into some alternative chiral backbones along with our initial attempt to apply these in a potentially concise asymmetric synthesis of delta lactones.The original catalyst design presumed the primary amine terminus of the catalyst would bind ketones and activate hy
Ruthenium(III) Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids  [PDF]
Zhiwen Xi,Wenyan Hao,Pingping Wang,Mingzhong Cai
Molecules , 2009, DOI: 10.3390/molecules14093528
Abstract: Ruthenium(III) chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature) in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.
Transfer Hydrogenation of Ketones Using Recyclable (η6-Arene) Ruthenium(II) Naphthylazo-p-Methyl Phenolate Complex
pMathiyazhagan Ulaganatha Raja, Nandhagopal RajaRengan Rameshppp
The Open Catalysis Journal , 2008, DOI: 10.2174/1876214X01003010030]
Abstract: Recyclable (η6-p-cymene)-ruthenium(II) 2-naphthylazo-p-methylphenolate catalyst of formulation [RuCl((η6-pcymene)( L)] (where L = mono anionic 2-naphthylazo-p-methylphenolate ligand) is shown to be an efficient catalyst for transfer hydrogenation of a wide range of alkyl and aryl ketones in the presence of 2-propanol and KOH.
Ruthenium-Catalyzed Selective Hydrogenation of bis-Arylidene Tetramic Acids. Application to the Synthesis of Novel Structurally Diverse Pyrrolidine-2,4-diones  [PDF]
Christos S. Karaiskos,Dimitris Matiadis,John Markopoulos,Olga Igglessi-Markopoulou
Molecules , 2011, DOI: 10.3390/molecules16076116
Abstract: Catalytic hydrogenation of 3,5-bis-arylidenetetramic acids, known for their biological activity, has been developed. The chemoselective ruthenium-catalyzed reduction of the exocyclic carbon-carbon double bonds on pyrrolidine-2,4-dione ring system, containing other reducible functions, has been investigated. Depending on the substrate the yield of the hydrogenation process can reach up to 95%. The structural elucidation has been established using NMR and HRMS spectral data.
Effects of Yttrium Doping on the Performance of Ru-Based Catalysts for Hydrogenation of Fatty Acid Methyl Ester  [PDF]
Qi Lin, Huirong Zheng, Guocai Zheng, Xinzhong Li, Benyong Lou
International Journal of Organic Chemistry (IJOC) , 2014, DOI: 10.4236/ijoc.2014.44025
Abstract: The highly dispersed supported ruthenium-yttrium (Ru-Y) bimetallic catalysts were prepared by impregnation method and their catalytic performance for hydrogenation of ester was fully investigated. The catalyst was characterized by X-ray diffraction and field emission scanning electron microscopy. The results show that the average particle diameter of the bimetallic crystallites was less than 10 nm. The effects of the reaction temperature, the hydrogen pressure, the amount of catalyst and the proportion of yttrium in catalyst on the hydrogenation of ester were studied. The experimental results show that the introduction of yttrium not only changed the chemical and textural properties of ruthenium-based catalyst but also controlled the formation of Ru-Y alloy. The Ru-Y catalyst (Ru-2%Y/TiO2) exhibited high catalytic activity and good selectivity towards the higher alcohols. Under optimal reaction conditions of 240°C and 5 MPa hydrogen pressure, the conversion of palm oil esters was above 93.4% while the selectivity towards alcohol was above 99.0%.
The effects of yttrium on the hydrogenation performance and surface properties of a ruthenium-supported catalyst
Journal of the Serbian Chemical Society , 2005,
Abstract: The effects of yttrium on the hydrogenation performance and surface properties of a Ru/sepiolite catalyst were studied. With CO2 methanation and CS2 poisoning as the testing reactons, TPR, TPD, XRD and CO chemisorption as the characterizations, the results showed that the presence of yttrium can increase the hydrogenation activity and anti-poisoning capacity of the Ru/sepiolite catalyst, which is due to a change of surface properties of the Ru/sepiolite. In the process of the catalytic reaction, the adjusting behavior of yttrium for the Ru/sepiolite catalyst aids in increasing the catalytic activity and anti-poisoning capacity of the catalyst.
Studies on the Iron Nanoparticles Catalyzed Reduction of Substituted Aromatic Ketones to Alcohols  [PDF]
L. Parimala,J. Santhanalakshmi
Journal of Nanoparticles , 2014, DOI: 10.1155/2014/156868
Abstract: Iron nanoparticles are synthesized and size characterized using HRTEM, FESEM, and XRD. Polyethylene glycol(PEG), carboxymethyl cellulose (CMC), and poly N-vinyl pyrrolidone (PVP) are used as nanoparticle stabilizers. The sizes of Fe nps are found to be 9?nm, 14?nm, and 17?nm?±?1?nm corresponding to PEG, CMC, and PVP stabilizers, respectively. The three different iron nanoparticles (Fe nps) prepared are used as catalysts in the hydrogenation reaction of various substituted aromatic ketones to alcohols with NaBH4. The progress of the reaction was monitored using time variance UV spectra. Kinetic plots are made from the absorbance values and the pseudo first order rate coefficient values are determined. Catalytic efficiency of the Fe nps is obtained by comparing the pseudo first order rate coefficient values, times of reaction, and % yield. Fe-PEG nps was found to act as better catalyst than Fe-CMC nps and Fe-PVP nps. Also, effects of substituents in the aromatic ring of ketones reveal that +I substituents are better catalysed than –I substituents. 1. Introduction Reduction reactions of carbonyl compounds to primary and secondary alcohols possess one of the important classes of organic reactions that are well used in synthetic chemistry [1–5]. Such reactions find immense applications in chemical industries related to fine chemicals, pharmaceuticals, perfumes, and agrochemicals. Transition metal catalyzed reduction reactions are considered as popular substitutes of platinum metal based catalysts. Cost effectiveness, abundance, stability, recyclability, environmentally benign, and relatively nontoxic are some of the reasons for the important role of tranisition metals in catalysis. Decades of research involve traditional catalysts for ketone hydrogenation reactions involving precious metals and their coordination complexes [6–12]. Rhodium and ruthenium complexes using chiral phosphines and amines as ligands show excellent catalytic activity towards asymmetric hydrogenation of prochiral ketones and other carbonyl compounds. However, these catalysts have limited applications because of their high cost and difficulty in the separation of products from chiral catalyst. There have been several attempts to develop iron catalysts for these kinds of reactions, because these would be cheaper and nontoxic [13, 14]. In this regard, Chirik’s, Beller’s, and Nishiyama’s groups have recently reported useful iron catalysts for the hydrosilation of aldehydes and ketones [7, 15] and their transfer hydrogenation. Efforts to find catalysts that do not require noble metals are
Ruthenium dioxide nanoparticles in ionic liquids: synthesis, characterization and catalytic properties in hydrogenation of olefins and arenes
Rossi, Liane M.;Dupont, Jairton;Machado, Giovanna;Fichtner, Paulo F. P.;Radtke, Claúdio;Baumvol, Israel J. R.;Teixeira, Sergio R.;
Journal of the Brazilian Chemical Society , 2004, DOI: 10.1590/S0103-50532004000600018
Abstract: the reaction of nabh4 with rucl3 dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (bmi.pf6) ionic liquid is a simple and reproducible method for the synthesis of stable ruo2 nanoparticles with a narrow size distribution within 2-3 nm. ruo2 nanoparticles were characterized by xrd, xps, eds and tem. these nanoparticles showed high catalytic activity either in the solventless or liquid-liquid biphasic hydrogenation of olefins and arenes under mild reaction conditions. hg(0) and cs2 poisoning experiments and xrd and tem analysis of particles isolated after catalysis indicated the formation of ru(0) nanoparticles. the nanoparticles could be re-used in solventless conditions up to 10 times in the hydrogenation of 1-hexene yielding a total turnover number for exposed ru atoms of 175,000.
Catalytic Asymmetric Hydrogenation of 3-Substituted Benzisoxazoles  [PDF]
Ryuhei Ikeda,Ryoichi Kuwano
Molecules , 2012, DOI: 10.3390/molecules17066901
Abstract: A variety of 3-substituted benzisoxazoles were reduced with hydrogen using the chiral ruthenium catalyst, {RuCl(p-cymene)[(R,R)-(S,S)-PhTRAP]}Cl. The ruthenium-catalyzed hydrogenation proceeded in high yield in the presence of an acylating agent, affording a-substituted o-hydroxybenzylamines with up to 57% ee. In the catalytic transformation, the N–O bond of the benzisoxazole substrate is reductively cleaved by the ruthenium complex under the hydrogenation conditions. The C–N double bond of the resulting imine is saturated stereoselectively through the PhTRAP–ruthenium catalysis. The hydrogenation produces chiral primary amines, which may work as catalytic poisons, however, the amino group of the hydrogenation product is rapidly acylated when the reaction is conducted in the presence of an appropriate acylating agent, such as Boc2O or Cbz-OSu.
Carbon dioxide hydrogenation catalyzed by ruthenium complexes immobilized on MCM-41

YU Ying-min,FEI Jin-hua,ZHANG Yi-ping,ZHENG Xiao-ming,

燃料化学学报 , 2006,
Abstract: Two kinds of immobilized Ru catalysts were synthesized by anchoring different ruthenium complexes on the functionalized mesoporous MCM-41 and then characterized with elemental analysis, atomic absorption spectrophotometer, UV-Vis and FT-IR. Hydrogenation of carbon dioxide to formate was investigated over these catalysts in CO2-expanded solvent. The effects of solvents and bases on the catalyst activity were also examined. These two catalysts are different in their activities and stabilities, especially at lower temperature and hydrogen partial pressure. High formate yield is obtained and no byproduct is detected. The immobilized Ru catalysts are promising in industry due to the facility in catalyst separation and reuse.
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