- Modification of rhodium catalyst with stibines for hydroformylation of 1-pentene
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Homogeneous hydroformylation of 1-pentene under synthesis gas experimental conditions was studied using RhClCO(PPh3)2 complex with different triarylstibines. Three different stibine ligands SbR3 [where R = 2,4,6-mesityl (TMS), 2-furyl (TFS), 2-N,N-dimethylbenzylamine (TDMBAS)], have been tested. It is interesting to note that 2:1 addition of these stibine ligands to the RhClCO(PPh3)2 complex catalyst increases the aldehydes yields with an appreciable n:iso ratio. The catalytic activity of the system shows a TDMBAS > TMS > TFS pattern which indicates that not only basicity of the ligand alone is playing a role in the activity but the steric effect is also very important, and it is combination of these two factors that contributes to the resulting catalytical activity. The maximum yield of aldehydes obtained were 98.7% with n/iso = 1.4 when RhClCO(PPh3)2 + TFS system was used and 93.7% with n/iso = 2.43 when TDMBAS ligand was studied.
- Sharma, Pankaj,Arias, Jose Luis,Vasquez, Jaime,Gomez, Valente,Guiterrez, Rene
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- Pyridine-triazole ligands for copper-catalyzed aerobic alcohol oxidation
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A series of Cu(NN′)2(OTf)2 complexes containing pyridine-triazole ligands [OTf = OSO2CF3; NN′ = NN′Ph (1), NN′hex (2), NN′py (3)] with different substituents at the triazole N4 position or 2,2′-bipyridine (bpy; 4) have been synthesized. Crystal structures of 1 and 3 reveal a trans-isomer with strong preference for regular-type triazole coordination (for 3) whereas the Cu-bipyridine complex 4 is more stable in a cis-form. Cyclic voltammetry of 1-4 suggest that the electron-donating strength follows the trend: bpy > NN′py > NN′hex ~ NN′Ph. The catalyst systems consisting of 5 mol% Cu(OTf)2/NN′/TEMPO (TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxy) in the presence of 2 × 2.0 cm2 Cu0 sheets as a reducing agent and 10 mol% N-methylimidazole (NMI) exhibit good activities for aerobic oxidation of benzyl alcohol to benzaldehyde. Catalytic studies have shown that the activities were higher with more electron-rich N-based ligands. Furthermore, oxidation of aliphatic alcohols such as 1-hexanol and 2-methyl-1-pentanol using the Cu catalyst system with the NN′py ligand at room temperature afforded the corresponding aldehydes in >99% and 46% yields, respectively after 24 h.
- Thongkam, Pech,Jindabot, Sudarat,Prabpai, Samran,Kongsaeree, Palangpon,Wititsuwannakul, Taveechai,Surawatanawong, Panida,Sangtrirutnugul, Preeyanuch
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- 1-Pentene Hydroformylation Catalyzed by Polymer-Bound Ruthenium Complexes
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Polymer-bound ruthenium hydroformylation catalysts were prepared by reacting diphenylphosphinated styrene-1percent divinylbenzene resins with Ru(CO)3(PPh3)2 under a carbon monoxide atmosphere.Resins with 29percent and 5percent ring-substitution loading levels of phosphine were prepared, and resins with P/Ru ratios of 3.1, 6.7, and 11.3 were made with the 29percent phosphine loading.These resins functioned as 1-pentene hydroformylation catalysts and were compared to the homogeneous use of Ru(CO)3(PPh3)2 as the catalyst.No olefin isomerization occured.The resin catalysts with P/Ru ratios of 3.1 and 6.7 at 29percent loading gave higher n/b aldehyde selectivities (3.5-3.8) than the homogeneous catalyst when employed at P/Ru ratios of 20 but not as high as was achieved by using Ru(CO)3(PPh3)2 in molten PPh3 (5.1).The n/b selectivity was discussed in terms of the equilibrium between (polymer-PPh2)2RuH2(alkene)(CO) and polymer-PPh2RuH2(alkene)(CO)2 within the resin matrix where phosphine loading, P/Ru, ligand mobility, and swelling play contributing roles.The novel 1,1'-bis(diphenylphosphino)ferrocene ligand induced higher n/b selectivities than PPh3 in homogeneous Ru-catalyzed reactions.
- Pittman, Charles U.,Wilemon, Gary M.
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- Recycling of two molecular catalysts in the hydroformylation/aldol condensation tandem reaction using one multiphase system
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Tandem reactions are of great importance to efficiently execute multiple conversions in one synthesis step. Herein we present a multiphase system for the hydroformylation/aldol condensation, which is able to recycle both optimized catalysts multiple times. The system consists of an organometallic rhodium/sulfoXantphos hydroformylation catalyst and basic NaOH as aldol condensation initiator, which are both immobilized in a polyethylene glycol phase. Under reaction conditions, NaOH is converted to sodium formate, which is still able to catalyse the aldol condensation. The reaction and recycling are demonstrated by the conversion of 1-pentene to the corresponding aldol product in a recycling experiment. During nine consecutive runs, no significant loss of activity is found with an overall TON of 8700 in regard to the rhodium catalyst and an average rhodium leaching of only of 0.07% per run is observed.
- Leitner, Walter,Strohmann, Marc,Vorholt, Andreas J.,Vossen, Jeroen T.
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- The continuous self aldol condensation of propionaldehyde in supercritical carbon dioxide: A highly selective catalytic route to 2-methylpentenal
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The aldol reactions of propionaldehyde and butyraldehyde have been explored in supercritical CO2, scCO2, using an automated continuous flow reactor. The reaction was found to proceed over a variety of heterogeneous acidic and basic catalysts and with increased selectivity compared to using neat reactants.
- Stevens, James G.,Bourne, Richard A.,Poliakoff, Martyn
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- Synthesis of novel rhodium phosphite catalysts for efficient and selective isomerization-hydroformylation reactions
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New modular H8-BINOL-based phosphite ligands have been synthesized. High activity and regioselectivity has been achieved in the rhodium-catalyzed isomerization-hydroformylation of internal olefins. The active catalysts have been characterized by in situ NMR studies.
- Piras, Irene,Jennerjahn, Reiko,Jackstell, Ralf,Baumann, Wolfgang,Spannenberg, Anke,Franke, Robert,Wiese, Klaus-Diether,Beller, Matthias
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- n-pentane carbonylation with CO on sulfated zirconia: An in situ solid-state 13C NMR study
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Using 13C CP/MAS NMR, the first evidence has been obtained for n-pentane carbonylation with carbon monoxide into C6 aldehydes, ketones and carboxylic acids on a sulfated zirconia catalyst.
- Luzgin,Stepanov,Shmachkova,Kotsarenko
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- Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
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Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
- Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
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- Zeolite-Encaged Isolated Platinum Ions Enable Heterolytic Dihydrogen Activation and Selective Hydrogenations
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Understanding the unique behaviors of atomically dispersed catalysts and the origin thereof is a challenging topic. Herein, we demonstrate a facile strategy to encapsulate Ptδ+ species within Y zeolite and reveal the nature of selective hydrogenation over a Pt@Y model catalyst. The unique configuration of Pt@Y, namely atomically dispersed Ptδ+ stabilized by the surrounding oxygen atoms of six-membered rings shared by sodalite cages and supercages, enables the exclusive heterolytic activation of dihydrogen over Ptδ+···O2- units, resembling the well-known classical Lewis pairs. The charged hydrogen species, i.e., H+ and Hδ-, are active reagents for selective hydrogenations, and therefore, the Pt@Y catalyst exhibits remarkable performance in the selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols and of nitroarenes to arylamines.
- Dai, Weili,Deng, Xin,Guan, Naijia,Li, Landong,Liu, Runze,Ma, Ding,Qin, Bin,Qin, Xuetao,Wu, Guangjun
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supporting information
p. 20898 - 20906
(2021/12/14)
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- Heterogeneous catalytic condensation of propanal
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The aldol homocondensation of propanal was studied in the presence of a heterogeneous titanium oxide catalyst modified with amino acid (AA) l-norleucine. The effects of the temperature and l-norleucine content on the conversion of propanal and selectivity of the process were studied. The reaction products were identified, and possible mechanisms are considered. A new catalyst (5% AA on titanium dioxide) was developed for the synthesis of 2-methyl-2-pentenal with the selectivity >90%.
- Afaunov, A. A.,Bruk, L. G.,Flid, V. R.,Martsinkevich, E. M.
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p. 2031 - 2033
(2021/11/04)
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- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- Method for synthesizing fluorescent dye intermediate aldehyde by hydroformylation of 1,3-diene compound
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The invention discloses a method for synthesizing a fluorescent dye intermediate aldehyde by hydroformylation of 1,3-diene compound. The method comprises the following steps: S1, sequentially adding 0.01 mmol (1 mol%) of [Rh(cod)Cl]2, 0.1 mmol of a phosphine ligand(P/Rh=10/1) and 1 mmol of diene into a reaction flask, adding 1 ml of a solvent DMF, putting the reaction flask into a high-pressure reaction kettle, after the reaction is finished, transferring a mixed solution into a 25 mL glass bottle with 200 microliters of n-tridecane as an internal standard by using a rubber head dropper, and detecting; and S2, determining the product yield and the structure through a gas chromatograph and a nuclear magnetic resonance spectrum, wherein the obtained olefin conversion rate is larger than 99%, the aldehyde yield ranges from 61% to 99%, and the regioselectivity of the product aldehyde ranges from 70/30 to 100/0. According to the method disclosed by the invention, the separation and purification steps of aldehyde products are simplified, and the substrate of the dialkene hydroformylation reaction is excellent in universality.
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Paragraph 0053-0054; 0056-0057
(2021/08/07)
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- Catalyst composition containing bidentate phosphine ligand and application thereof
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The catalyst composition comprises a bidentate phosphine ligand and a rhodium complex, wherein the skeleton of the bidentate phosphine ligand not only has C. 2 The symmetry and the appropriate rigidity, and the phosphine ligand derived based on the skeleton can provide effective steric hindrance around the catalyst center metal, so that the selectivity of the catalyst can be remarkably improved, the aldehyde yield is not lower 92% when the catalyst combination is applied to the hydroformylation reaction, and the selectivity of n-aldehyde is not lower 90%. In addition, the raw materials olefins with different structures can obtain outstanding reaction rate and normal aldehyde selectivity as compared with the existing catalyst systems, and can be suitable for the hydroformylation reaction of more types of olefins.
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Paragraph 0068; 0081-0084
(2021/11/03)
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- A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid Drakaea micrantha
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Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed β-hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations.
- Bohman, Bj?rn,Tan, Monica M. Y.,Phillips, Ryan D.,Scaffidi, Adrian,Sobolev, Alexandre N.,Moggach, Stephen A.,Flematti, Gavin R.,Peakall, Rod
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supporting information
p. 1124 - 1128
(2019/12/24)
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- Synthesis and Biochemical Evaluation of Nicotinamide Derivatives as NADH Analogue Coenzymes in Ene Reductase
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Nicotinamide and pyridine-containing conjugates have attracted a lot of attention in research as they have found use in a wide range of applications including as redox flow batteries and calcium channel blockers, in biocatalysis, and in metabolism. The interesting redox character of the compounds’ pyridine/dihydropyridine system allows them to possess very similar characteristics to the natural chiral redox agents NAD+/NADH, even mimicking their functions. There has been considerable interest in designing and synthesizing NAD+/NADH mimetics with similar redox properties. In this research, three nicotinamide conjugates were designed, synthesized, and characterized. Molecular structures obtained through X-ray crystallography were obtained for two of the conjugates, thereby providing more detail on the bonding and structure of the compounds. The compounds were then further evaluated for biochemical properties, and it was found that one of the conjugates possessed similar functions and characteristics to the natural NADH. This compound was evaluated in the active enzyme, enoate reductase; like NADH, it was shown to help reduce the C=C double bond of three substrates and even outperformed the natural coenzyme. Kinetic data are reported.
- Falcone, Natashya,She, Zhe,Syed, Jebreil,Lough, Alan,Kraatz, Heinz-Bernhard
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p. 838 - 845
(2019/02/07)
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- Highly practical and efficient preparation of aldehydes and ketones from aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst
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Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations.
- Zhang, Mengqi,Zhai, Yongyan,Ru, Shi,Zang, Dejin,Han, Sheng,Yu, Han,Wei, Yongge
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supporting information
p. 10164 - 10167
(2018/09/13)
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- Double tooth phosphine ligand and its application in the hydroformylation reaction (by machine translation)
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The invention discloses a double-phosphine ligand, its general structure is represented by the formula; in the above formula, Ph is phenyl, a, b, c, d, e, f, g, h are the same or different, selected from H, R, OR, NR2 , NO2 Or cyano, R is alkyl or substituted alkyl. The double-phosphine ligand and the transition metal complex to make the metal - phosphine ligand complex can be used for the hydroformylation reaction catalyst, has high activity and linear selectively, in particular based on selected from transition metal Co, Rh complex; and catalytic reaction the amount of phosphine ligand is greatly reduced. The invention of the double-phosphine ligand easy synthesis, low cost of raw materials. (by machine translation)
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Paragraph 0056-0061
(2018/10/19)
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- Bidentate phosphine ligand and application thereof in hydroformylation reaction
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The invention discloses a bidentate phosphine ligand. A structural formula of the bidentate phosphine ligand is shown in a following formula, wherein Ph is phenyl; a, b, c, d, e, f, g and h are the same or different, and are selected from H, R or Ar; R is alkyl or substituted alkyl; Ar is aryl or substituted aryl. A metal-phosphine ligand prepared from the bidentate phosphine ligand and transitionmetals is a catalyst for the hydroformylation reaction, has high activity and linear selectivity, and is a complex from transition metals Co (cobalt) and Rh (rhodium); the usage amount of phosphine ligand in the catalysis reaction is greatly reduced. The bidentate phosphine ligand has the advantages that the synthesizing is easy, and the cost of the raw materials is low. The formula is shown in the attached figure.
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Paragraph 0052-0058
(2018/12/02)
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- BIDENTATE DIPHOSPHORAMIDITES WITH A HOMOPIPERAZINE GROUP AS LIGANDS FOR HYDROFORMYLATION
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The invention relates to Rh, Ru, Co and Ir complexes comprising bidentate diphosphoramidites as ligands and to the use thereof as catalysts for the hydroformylation of olefins. The invention also relates to a process for preparing an aldehyde from an olefin using the complexes or ligands mentioned.
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Paragraph 0076; 0077
(2017/07/14)
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- Rhodium-Complex-Catalyzed Hydroformylation of Olefins with CO2and Hydrosilane
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A rhodium-catalyzed one-pot hydroformylation of olefins with CO2, hydrosilane, and H2has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies indicate that the transformation is likely to proceed through a tandem sequence of poly(methylhydrosiloxane) (PMHS) mediated CO2reduction to CO and a conventional rhodium-catalyzed hydroformylation with CO/H2. The hydrosilylane-mediated reduction of CO2in preference to aldehydes was found to be crucial for the selective formation of aldehydes under the reaction conditions.
- Ren, Xinyi,Zheng, Zhiyao,Zhang, Lei,Wang, Zheng,Xia, Chungu,Ding, Kuiling
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supporting information
p. 310 - 313
(2016/12/30)
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- Enhanced Ene-Reductase Activity through Alteration of Artificial Nicotinamide Cofactor Substituents
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The reduction of activated C=C double bonds is an important reaction in synthetic chemistry owing to the potential formation of up to two new stereogenic centers. Artificial nicotinamide cofactors were recently presented as alternative suppliers of hydride equivalents needed for alkene reduction. To study the effect of cofactors on the reduction of activated alkenes, a set of N-substituted synthetic nicotinamide cofactors with differing oxidation potentials were synthesized and their electrochemical and kinetic behavior was studied. The effects of the synthetic cofactors on enzyme activity of four ene reductases are outlined in this study, where the cofactor mimic with an N-substituted 4-hydroxy-phenyl residue led to a sixfold higher vmax relative to the natural cofactor NADH. Artificial nicotinamide cofactor substituents: A set of N-substituted synthetic nicotinamide cofactors with differing oxidation potentials were synthesized and their electrochemical and kinetic behavior was studied. The effects of the synthesized cofactors on the enzyme activity of four ene reductases are outlined. The cofactor mimic with an N-substituted 4-hydroxy-phenyl residue led to a sixfold higher vmax relative to the natural cofactor NADH.
- L?w, Sebastian A.,L?w, Isabell M.,Weissenborn, Martin J.,Hauer, Bernhard
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p. 911 - 915
(2016/03/15)
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- Systematic methodology for the development of biocatalytic hydrogen-borrowing cascades: Application to the synthesis of chiral α-substituted carboxylic acids from α-substituted α,β-unsaturated aldehydes
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Ene-reductases (ERs) are flavin dependent enzymes that catalyze the asymmetric reduction of activated carbon-carbon double bonds. In particular, α,β-unsaturated carbonyl compounds (e.g. enals and enones) as well as nitroalkenes are rapidly reduced. Conversely, α,β-unsaturated esters are poorly accepted substrates whereas free carboxylic acids are not converted at all. The only exceptions are α,β-unsaturated diacids, diesters as well as esters bearing an electron-withdrawing group in α- or β-position. Here, we present an alternative approach that has a general applicability for directly obtaining diverse chiral α-substituted carboxylic acids. This approach combines two enzyme classes, namely ERs and aldehyde dehydrogenases (Ald-DHs), in a concurrent reductive-oxidative biocatalytic cascade. This strategy has several advantages as the starting material is an α-substituted α,β-unsaturated aldehyde, a class of compounds extremely reactive for the reduction of the alkene moiety. Furthermore no external hydride source from a sacrificial substrate (e.g. glucose, formate) is required since the hydride for the first reductive step is liberated in the second oxidative step. Such a process is defined as a hydrogen-borrowing cascade. This methodology has wide applicability as it was successfully applied to the synthesis of chiral substituted hydrocinnamic acids, aliphatic acids, heterocycles and even acetylated amino acids with elevated yield, chemo- and stereo-selectivity. A systematic methodology for optimizing the hydrogen-borrowing two-enzyme synthesis of α-chiral substituted carboxylic acids was developed. This systematic methodology has general applicability for the development of diverse hydrogen-borrowing processes that possess the highest atom efficiency and the lowest environmental impact. This journal is
- Knaus, Tanja,Mutti, Francesco G.,Humphreys, Luke D.,Turner, Nicholas J.,Scrutton, Nigel S.
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supporting information
p. 223 - 233
(2015/02/19)
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- Selective N-alkylation of indoles with primary alcohols using a pt/HBEA catalyst?
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Pt-loaded HBEA (H+-exchanged BEA zeolite) is found to be an effective and reusable heterogeneous catalyst for regioselective N-alkylation of indoles with primary aliphatic and benzylic alcohols under additive-free conditions driven by the borrowing-hydrogen methodology. Structural and mechanistic studies suggest a cooperative mechanism of the Pt0 site on Pt metal clusters and the Br?nsted acid site of the zeolite, in which the Pt0 site is responsible for dehydrogenation/hydrogenation steps and the Br?nsted acid site is responsible for the regioselective condensation of indoles with aldehydes to the enamine intermediate.
- Hakim Siddiki,Kon, Kenichi,Shimizu, Ken-Ichi
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supporting information
p. 173 - 177
(2018/04/16)
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- Advantages of the solventless hydroformylation of olefins
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Abstract The hydroformylation of olefins using Rh(acac)(CO)2 as a catalyst with the excess of PPh3 was investigated at the temperature of 80°C within the pressure range from 4 to 12 bar in a neat substrate, without a solvent. The conversion of 1-hexene was complete, with a linear-to-branched aldehyde ratio of ca. 10. Very good results were also obtained for 1-pentene and 1-octene. The catalytic performance of the Rh(acac)(CO)2/PPh3 catalytic system in hydroformylation under solventless conditions was better than that in toluene, owing to the high concentration of the reactants. Recycling experiments confirmed the good stability of the catalyst and its constant activity.
- Alsalahi,Trzeciak
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p. 147 - 151
(2015/08/18)
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- Jet loop reactor having nanofiltration
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The invention relates to a device for the continuous, homogeneous-catalysis reaction of a liquid with a gas and optionally an additional fluid, wherein the device comprises at least one reactor having an external liquid circulation driven by a pump, and wherein the device has at least one membrane separation stage that preferably holds back the homogeneous catalyst. The aim of the invention is to specify a device that allows homogeneous-catalysis gas/liquid phase reactions, in particular hydroformylations, which operate with membrane separation of the catalyst to be performed economically at an industrially relevant scale. Said aim is achieved in that a jet loop reactor is provided as the reactor, and that the pump and the membrane separation stage are arranged in the same external liquid circuit.
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Page/Page column 13
(2015/10/28)
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- Crucial role of additives in iridium-catalyzed hydroformylation
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Abstract This paper presents the new highly selective iridium-catalyzed hydroformylation of 1-octene with an Ir(cod)(acac)/PPh3/salt catalyst system. The addition of inorganic salts such as LiCl suppresses the hydrogenation of 1-octene and increases the yield of desired hydroformylation products. Even low amounts of LiCl (LiCl/Ir = 2/1) significantly increase the chemoselectivity of aldehydes up to 94% with a 1-octene conversion of 90% within 7 h. This catalyst is applicable to other alkenes such as 1-pentene or 1-dodecene. The high selectivities and the remarkable activity of the optimized iridium catalyst are promising in terms of successfully implementing on an industrial scale in the future.
- Behr, Arno,K?mper, Alexander,Nickel, Martin,Franke, Robert
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p. 243 - 248
(2015/09/01)
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- METHOD FOR HYDROFORMYLATION OF UNSATURATED COMPOUNDS
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The invention relates to a method for hydroformylation of unsaturated compounds such as olefins and alkynes using mixtures of synthesis gas (CO/H2), in which either the unsaturated compounds and a catalyst are heated to a reaction temperature of 60 to 200° C. and the synthesis gas is then added, or the unsaturated compounds and the catalyst are brought into contact with pure CO at normal temperature in a preformation step, then are heated to reaction temperature and on reaching the reaction temperature the CO is replaced by the synthesis gas. The pressure is 1 to 200 bar and the CO:H2 ratio in the synthesis gas is in the range from 1:1 to 50:1. The iridium catalyst used comprises a phosphorus-containing ligand in the iridium:ligand ratio in the range from 1:1 to 1:100. With high catalyst activities and low catalyst use, very high turnover frequencies are achieved.
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Paragraph 0089
(2014/02/16)
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- Steric effects and mechanism in the formation of hemi-acetals from aliphatic aldehydes
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Some physical properties (pKa, log POW, boiling points) of hexanoic acid 1 (X = COOH) and its seven isomers 2, 3, 4, 5, 6, 7, 8 (X = COOH) are reported. Hexanal 1 (X = CHO) and its seven isomeric aldehydes 2, 3, 4, 5, 6, 7, 8 (X = CHO) are shown to equilibrate, in methanol solution, with their hemi-acetals. Logarithms of equilibrium constants correlate with values of Es for the isomeric C5H11 substituents, and with logs of relative rates for saponification of the corresponding methyl esters with ρ = 0.52, reflecting the reduced steric demand of hydrogen compared to oxygen in the quaternization of ester and aldehydic carbonyl groups. Rates of equilibration have also been measured in buffered methanol. For hexanal, with a 2:1 Et3N:AcOH buffer, the buffer-independent contribution is dominated by the methoxide catalysed pathway. Rates in this medium have been determined for isomers 1, 2, 3, 4, 5, 6, 7, 8 (X = CHO), and their logarithms do not correlate with logarithms of equilibrium constants for hemi-acetal formation or with substituent steric parameters derived from ester formation or saponification, indicating that the steric changes associated with full quaternization of the carbonyl group are not mirrored in the transition structures for hemi-acetal formation. It is suggested that transition states for hemi-acetal formation are relatively early so that steric interactions are effectively those between the nucleophile and ground state conformations of the aldehydes. A comparison of the entropies of hemi-acetal formation with entropies of activation has provided a basis for a suggested transition structure. Comparisons with acid chloride hydrolyses are made. Copyright 2013 John Wiley & Sons, Ltd. Logarithms of equilibrium constants for formation hemi-acetals of hexanal and its seven isomeric aldehydes correlate well with values of Es for the isomeric C5H11 substituents, and with logs of relative rates for saponification of the corresponding methyl esters. Logarithms of rate constants for hemi-acetal formation do not, indicating that the steric changes associated with full quaternization of the carbonyl group are not mirrored in the transition structures for hemi-acetal formation. The reasons for this are discussed. Copyright
- Daw, Graham,Regan, Andrew C.,Watt, C. Ian F.,Wood, Evan
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p. 1048 - 1057
(2014/01/06)
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- Ligand-modified rhodium catalysts on porous silica in the continuous gas-phase hydroformylation of short-chain alkenes-catalytic reaction in liquid-supported aldol products
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Ligand-modified Rh complexes were physically adsorbed on the surface of porous silica. The resulting materials were subjected to the continuous gas-phase hydroformylation of C2 and C4 alkenes. The ligands used for catalyst modification were bidentate phosphorus ligands known from the literature, namely, sulfoxantphos (1) and a benzopinacol-based bulky diphosphite 2. The tested catalyst materials were active and, in particular, selective as in comparable homogeneous liquid-phase experiments. Long-term stability experiments over 1000h on stream showed minor deactivation. A significant increase in the catalyst mass after the reaction was detected by weighing and thermogravimetric analysis. By using headspace-GC-MS, the mass increase could be attributed to high-boiling compounds, which are formed insitu during the catalytic reaction itself and accumulate inside the pores of the support. Evidence is given that the initially physisorbed catalyst complexes dissolve in the high-boiling aldol side-products, which are suitable solvents for the active catalyst species and provide a liquid-phase environment held by capillary forces on the support. It's all in the pores! Ligand-modified Rh complexes are physically adsorbed onto the surface of porous silica and the resulting solid materials are subjected to continuous gas-phase hydroformylation of C2 and C4 alkenes. The catalyst materials were surprisingly active and, in particular, exhibited similar selectivity to liquid-phase reactions.
- Schoenweiz, Andreas,Debuschewitz, Jonas,Walter, Simon,Woelfel, Rene,Hahn, Hanna,Dyballa, Katrin M.,Franke, Robert,Haumann, Marco,Wasserscheid, Peter
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p. 2955 - 2963
(2013/10/21)
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- Chemo- and regioselective homogeneous rhodium-catalyzed hydroamidomethylation of terminal alkenes to N-alkylamides
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A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through catalytic hydroamidomethylation with 1-pentene and acetamide as model substrates. For appropriate catalyst performance, it appears to be essential that catalytic amounts of a strong acid promoter, such as p-toluenesulfonic acid (HOTs), as well as larger amounts of a weakly acidic protic promoter, particularly hexafluoroisopropyl alcohol (HORF) are applied. Apart from the product N-1-hexylacetamide, the isomeric unsaturated intermediates, hexanol and higher mass byproducts, as well as the corresponding isomeric branched products, can be formed. Under optimized conditions, almost full alkene conversion can be achieved with more than 80 % selectivity to the product N-1-hexylamide. Interestingly, in the presence of a relatively high concentration of HORF, the same catalyst system shows a remarkably high selectivity for the formation of hexanol from 1-pentene with syngas, thus presenting a unique example of a selective rhodium-catalyzed hydroformylation-hydrogenation tandem reaction under mild conditions. Time-dependent product formation during hydroamidomethylation batch experiments provides evidence for aldehyde and unsaturated intermediates; this clearly indicates the three-step hydroformylation/condensation/hydrogenation reaction sequence that takes place in hydroamidomethylation. One likely role of the weakly acidic protic promoter, HORF, in combination with the strong acid HOTs, is to establish a dual-functionality rhodium catalyst system comprised of a neutral rhodium(I) hydroformylation catalyst species and a cationic rhodium(III) complex capable of selectively reducing the imide and/or ene-amide intermediates that are in a dynamic, acid-catalyzed condensation equilibrium with the aldehyde and amide in a syngas environment. Taking control: A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through the new catalytic hydroamidomethylation reaction (see picture). Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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p. 1759 - 1773
(2013/10/21)
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- Biocatalytic asymmetric alkene reduction: Crystal structure and characterization of a double bond reductase from Nicotiana tabacum
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The application of biocatalysis for the asymmetric reduction of activated C=C is a powerful tool for the manufacture of high-value chemical commodities. The biocatalytic potential of "-ene" reductases from the Old Yellow Enzyme (OYE) family of oxidoreductases is well-known; however, the specificity of these enzymes toward mainly small molecule substrates has highlighted the need to discover "-ene" reductases from different enzymatic classes to broaden industrial applicability. Here, we describe the characterization of a flavin-free double bond reductase from Nicotiana tabacum (NtDBR), which belongs to the leukotriene B4 dehydrogenase (LTD) subfamily of the zinc-independent, medium chain dehydrogenase/reductase superfamily of enzymes. Using steady-state kinetics and biotransformation reactions, we have demonstrated the regio- and stereospecificity of NtDBR against a variety of α,β-unsaturated activated alkenes. In addition to catalyzing the reduction of typical LTD substrates and several classical OYE-like substrates, NtDBR also exhibited complementary activity by reducing non-OYE substrates (i.e., reducing the exocyclic C=C double bond of (R)-pulegone) and in some cases showing an opposite stereopreference in comparison with the OYE family member pentaerythritol tetranitrate (PETN) reductase. This serves to augment classical OYE "-ene" reductase activity and, coupled with its aerobic stability, emphasizes the potential industrial value of NtDBR. Furthermore, we also report the X-ray crystal structures of the holo-, binary NADP(H)-bound, and ternary [NADP+ and 4-hydroxy-3-methoxycinnamaldehyde (9a)-bound] NtDBR complexes. These will underpin structure-driven site-saturated mutagenesis studies aimed at enhancing the reactivity, stereochemistry, and specificity of this enzyme.
- Mansell, David J.,Toogood, Helen S.,Waller, John,Hughes, John M.X.,Levy, Colin W.,Gardiner, John M.,Scrutton, Nigel S.
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p. 370 - 379
(2013/08/25)
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- Selective oxoammonium salt oxidations of alcohols to aldehydes and aldehydes to carboxylic acids
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The oxidation of alcohols to aldehydes using stoichiometric 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) in CH2Cl2 at room temperature is a highly selective process favoring reaction at the carbinol center best able to accommodate a positive charge. The oxidation of aldehydes to carboxylic acids by 1 in wet acetonitrile is also selective; the rate of the process correlates with the concentration of aldehyde hydrate. A convenient and high yield method for oxidation of alcohols directly to carboxylic acids has been developed.
- Qiu, Joseph C.,Pradhan, Priya P.,Blanck, Nyle B.,Bobbitt, James M.,Bailey, William F.
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supporting information; experimental part
p. 350 - 353
(2012/03/09)
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- Highly practical copper(I)/TEMPO catalyst system for chemoselective aerobic oxidation of primary alcohols
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Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O2 as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)CuI/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary alcohols, including allylic, benzylic, and aliphatic derivatives, to the corresponding aldehydes using readily available reagents, at room temperature with ambient air as the oxidant. The catalyst system is compatible with a wide range of functional groups and the high selectivity for 1° alcohols enables selective oxidation of diols that lack protecting groups.
- Hoover, Jessica M.,Stahl, Shannon S.
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supporting information; experimental part
p. 16901 - 16910
(2011/12/04)
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- Enantioselective organocatalytic formal allylation of α-branched aldehydes
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Heteroarylvinyl sulfone 1 has been successfully used as a new sulfonyl Michael acceptor in aminocatalytic reactions with branched aldehydes. Subsequent one-pot Julia-Kocienski olefination allows the challenging preparation of enantiomerically pure α-allylated aldehydes bearing C-α quaternary carbons.
- Rodrigo, Eduardo,Morales, Sara,Duce, Sara,Ruano, Jose Luis Garcia,Cid, M. Belen
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supporting information; scheme or table
p. 11267 - 11269
(2011/12/05)
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- CONVERSION OF OXYGENATES TO HYDROCARBON FUELS BY DEOXYGENATION
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Oxygenates from biomass, particularly hydroxyl-substituted C2-plus hydrocarbons, are treated for removal of some or all of their oxygen atoms and for chain lengthening by carbon-carbon coupling in a single reaction medium in the gas phase over a solid catalyst.
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Page/Page column 32-33
(2011/10/10)
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- A general and efficient iridium-catalyzed hydroformylation of olefins
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Breaking with conventional wisdom: Hydroformylation catalysts are generally based on rhodium; earlier, cobalt was used. Iridium, which is less expensive than rhodium, was considered too unreactive. However, iridium/phosphine complexes have now been shown to form active catalysts for the hydroformylation of olefins under mild conditions (see scheme; R1, R2=H, alkyl, aryl; R3=H, alkyl). Competing hydrogenation side reactions can be suppressed. Copyright
- Piras, Irene,Jennerjahn, Reiko,Jackstell, Ralf,Spannenberg, Anke,Franke, Robert,Beller, Matthias
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experimental part
p. 280 - 284
(2011/02/28)
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- Phosphine-Borane complexes: In situ deprotection and application as ligands in the Rh- or Pd-Catalysed hydroformylation reaction
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Triarylphosphine-borane complexes are directly useful in the Rh-catalysed hydroformylation reaction of 1-octene (or Pdcatalysed hydroformylation of 1-pentene). Mild reaction conditions provide similar yields and selectivities of the anticipated aldehyde products to reactions making use of the corresponding free phosphines as ligands. The mono- or bidentate P-B adducts undergo in situ CO-mediated deprotection the produce the free phosphine ligands. The results demonstrate that phosphine-borane complexes may be directly applied to carbonylation reactions without a prior deprotection step, with little to no change in the reaction outcome.
- Williams,Kotze,Ferreira,Holzapfel
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experimental part
p. 240 - 246
(2012/01/03)
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- Focused Directed Evolution of Pentaerythritol Tetranitrate Reductase by Using Automated Anaerobic Kinetic Screening of Site-Saturated Libraries
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This work describes the development of an automated robotic platform for the rapid screening of enzyme variants generated from directed evolution studies of pentraerythritol tetranitrate (PETN) reductase, a target for industrial biocatalysis. By using a 96-well format, near pure enzyme was recovered and was suitable for high throughput kinetic assays; this enabled rapid screening for improved and new activities from libraries of enzyme variants. Initial characterisation of several single site-saturation libraries targeted at active site residues of PETN reductase, are described. Two mutants (T26S and W102F) were shown to have switched in substrate enantiopreference against substrates (E)-2-aryl-1-nitropropene and α-methyl-trans-cinnamaldehyde, respectively, with an increase in ee (62 % (R) for W102F). In addition, the detection of mutants with weak activity against α,β-unsaturated carboxylic acid substrates showed progress in the expansion of the substrate range of PETN reductase. These methods can readily be adapted for rapid evolution of enzyme variants with other oxidoreductase enzymes.
- Hulley, Martyn E.,Toogood, Helen S.,Fryszkowska, Anna,Mansell, David,Stephens, Gill M.,Gardiner, John M.,Scrutton, Nigel S.
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experimental part
p. 2433 - 2447
(2011/07/08)
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- Synthesis and C-alkylation of hindered aldehyde enamines
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A new reactivity mode of hindered lithium amides with terminal epoxides is described whereby aldehyde enamines are produced via a previously unrecognized reaction pathway. Some of these aldehyde enamines display unprecedented C-alkylation reactivity toward unactivated primary and secondary alkyl halides. For comparison, the reactivity of aldehyde enamines synthesized via a traditional condensation method was examined. C-rather than N-alkylation was the dominant reaction pathway found with a range of electrophiles, making this route to α-alkylated aldehydes more synthetically useful than previously reported.
- Hodgson, David M.,Bray, Christopher D.,Kindon, Nicholas D.,Reynolds, Nigel J.,Coote, Steven J.,Um, Joann M.,Houk
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body text
p. 1019 - 1028
(2009/07/04)
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- Rhodium-catalyzed hydroformylation of olefins: Effect of [bis(2,4-di-tert-butyl) pentaerythritol] diphosphite (alkanox P-24) on the regioselectivity of the reaction
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Rhodium (I) associated with [bis(2,4-di-tert-butyl) pentaerythritol] diphosphite (I) as a ligand represents an active catalyst system for highly regioselective hydroformylation of various alkenes. The commercially available bis(2,4-di-tert-butyl)pentaerythritol diphosphite (alkanox P-24) (I), which has been used so far as an antioxidant in the stabilization of polymers, was used as a diphosphite ligand for the selective hydroformylation reaction of olefins. Excellent selectivity towards linear aldehydes and excellent conversions were achieved in the hydroformylation of alkenes. The hydroformylation reaction was applied to various olefinic substrates including the internal alkenes.
- Tijani, Jimoh,El Ali, Bassam
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p. 3492 - 3497
(2008/02/12)
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- RuHCl(CO)(PPh3)3-catalyzed reductive dimerization of α,β-unsaturated aldehydes leading to α-hydroxymethyl ketones
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The reductive dimerization α,β-unsaturated aldehydes to give saturated ketones was achieved using RuHCl(CO)(PPh3)3 as a catalyst in the presence of secondary alcohols as hydrogen source. The reaction is likely to proceed via the hydroruthenation of α,β-unsaturated aldehydes followed by aldol reaction of the resultant ruthenium enolates with α,β-unsaturated aldehydes to give unsaturated α-hydroxymethyl ketones, which undergo transfer hydrogenation to give α-hydroxymethyl ketones. Georg Thieme Verlag Stuttgart.
- Doi, Takashi,Fukuyama, Takahide,Minamino, Satoshi,Ryu, Ilhyong
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p. 3013 - 3016
(2008/02/12)
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- Characterization of active sites over reduced Ni-Mo/Al2O 3 catalysts for hydrogenation of linear aldehydes
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Reduced Ni-Mo/Al2O3 catalysts exhibit a behavior analogous to that of sulfided Ni-Mo/Al2O3 catalysts in hydrogenation of linear aldehydes to alcohols. Similar to what has been previously reported for sulfided catalysts, NO and CO2 can be used over the reduced Ni-Mo catalysts as probe molecules for the active sites responsible for two competing reactions - aldehyde hydrogenation to alcohols and condensation reactions to heavy products, respectively. Reduced catalysts have a higher aldehyde conversion activity and alcohol selectivity than their sulfided counterparts. The reduction temperature has a strong effect on the surface density of anion vacancies, which are responsible for alcohol formation. Reduction temperature also plays a role in determining the abundance of OH groups on the alumina surface. The effect of reduction temperature also manifests itself through the differences seen in the oxidation states of Mo and Ni species.
- Wang, Xueqin,Ozkan, Umit S.
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p. 1882 - 1890
(2007/10/03)
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- Synthesis of linear aldehydes from internal olefins in water
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We show here, for the first time, that the carbonylation of internal olefins in a biphasic water system is possible. It is shown that control of the pH and CO partial pressure are important factors for successful reactions. Interestingly, the water-soluble catalyst leads to significantly higher regioselectivity compared to similar catalysts soluble in organic solvents. The obtained nli-selectivities exceed aD known literature data and the catalyst can be easily reused several times. The Royal Society of Chemistry 2005.
- Klein, Holger,Jackstell, Ralf,Beller, Matthias
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p. 2283 - 2285
(2007/10/03)
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- Reaction network of aldehyde hydrogenation over sulfided Ni-Mo/Al 2O3 catalysts
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A reaction network of aldehyde hydrogenation over NiMoS/Al 2O3 catalysts was studied with aldehydes with straight and branched carbon chains and different chain lengths as feed materials. The reactions in the gas phase and the liquid phase were compared. The main reaction in the aldehyde hydrogenation process is the hydrogenation of the CO double bond, which takes place over the coordinatively unsaturated sites. The major side reactions are self-condensation of aldehydes and condensation of aldehydes with alcohols. Both reactions involve α-hydrogen and are primarily catalyzed by acid-base bifunctional sites over the exposed Al2O 3 surfaces.
- Wang, Xueqin,Saleh, Ramzi Y.,Ozkan, Umit S.
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- Phenoxaphosphino-modified xantphos-type ligands in the rhodium-catalysed hydroformylation of internal and terminal alkenes
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The solubility of the modifying ligand is an important parameter for the efficiency of a rhodium-catalysed hydroformylation system. A facile synthetic procedure for the preparation of well-defined xanthene-type ligands was developed in order to study the influence of alkyl substituents at the 2-, and 7-positions of the 9,9-dimethylxanthene backbone and at the 2-, and 8-positions of the phenoxaphosphino moiety of ligands 1-16 on solubility in toluene and the influence of these substituents on the performance of the ligands in the rhodium-catalysed hydroformylation. An increase in solubility from 2.3 mmol·L-1 to > 495 mmol·L-1 was observed from the least soluble to the most soluble ligand. A solubility of at least 58 mmol·L-1 was estimated to be sufficient for a large-scale application of these ligands in hydroformylation. Highly active and selective catalysts for the rhodium-catalysed hydroformylation of 1-octene and trans-2-octene to nonanal, and for the hydroformylation of 2-pentene to hexanal were obtained by employing these ligands. Average rates of > 1600 (mol aldehyde) x (mol Rh)-1 x h-1 {conditions: p(CO/H 2) = 20 bar, T = 353 K, [Rh] = 1 mM, [alkene] = 637 mM} and excellent regio-selectivities of up to 99% toward the linear product were obtained when 1-octene was used as substrate. For internal olefins average rates of > 145 (mol aldehyde) x (mol Rh)-1 x h-1 {p(CO/ H2) = 3.6-10 bar, T = 393 K, [Rh] = 1 mM, [alkene] = 640-928 mM} and high regio-selectivities up to 91% toward the linear product were obtained.
- Bronger, Raymond P. J.,Bermon, Jochem P.,Herwig, Juergen,Kamer, Paul C. J.,Van Leeuwen, Piet W. N. M.
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p. 789 - 799
(2007/10/03)
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- Catalysis by water-soluble organometallic complexes in water-in-densified fluid microemulsions
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A microemulsion containing water, a densified fluid, a surfactant, and an organometallic catalyst is used to catalyze chemical reactions. The organometallic catalyst preferably has substantial solubility in the water phase of the microemulsion. Separation of reaction products from the microemulsion is facilitated by removal of the densified fluid.
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- Highly Selective Synthesis of Enamines from Olefins
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Astonishing chemoselectivity is observed in the rhodium-catalyzed formation of enamines from olefins, CO, H2, and amines (see scheme). This new reaction can be used with a broad range of substrates and is high-yielding and highly selective (n/iso = 99:1 in most cases).
- Ahmed, Moballigh,Seayad, Abdul Majeed,Jackstell, Ralf,Beller, Matthias
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p. 5615 - 5619
(2007/10/03)
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- A Convenient Nitroxyl Radical Catalyst for the Selective Oxidation of Primary and Secondary Alcohols to Aldehydes and Ketones by O2 and H2O2 under Mild Conditions
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A new macrocyclic tetrafunctional nitroxyl radical, I, developed by Ciba Specialty Chemicals, is a particularly effective catalyst in combination with Mn(II) and Co(II) or Cu(II) nitrates for the selective oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones by air or O 2 under mild conditions (ambient temperature and pressure) or H 2O2. A distinctive feature of I is the possibility of easy recovery and recycles, due to its low solubility, particularly as ammonium salt, in most organic solvents, which makes it especially useful for practical applications.
- Minisci, Francesco,Recupero, Francesco,Rodino, Marianna,Sala, Massimiliano,Schneider, Armin
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p. 794 - 798
(2013/09/05)
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- Amines made easily: A highly selective hydroaminomethylation of olefins
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A highly chemo- and regioselective hydroaminomethylation of simple as well as functionalized α-olefins using a cationic rhodium precatalyst together with Xantphos as ligand is reported. Studies of the influence of ligands and reaction conditions led to an unprecedented selective hydroaminomethylation procedure. The novel procedure constitutes an economically attractive and environmentally favorable synthesis of secondary and tertiary aliphatic amines.
- Ahmed, Moballigh,Seayad, Abdul Majeed,Jackstell, Ralf,Beller, Matthias
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p. 10311 - 10318
(2007/10/03)
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- Method for hydrogenating carbonyl compounds
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A process for the catalytic hydrogenation of a carbonyl compound or of a mixture of two or more carbonyl compounds in the presence of a catalyst which comprises an inorganic support containing TiO2, and as active component copper or a mixture of copper and at least one of the metals selected from the group of zinc, aluminum, cerium, a noble metal and a group VIII metal, wherein the copper surface area does not exceed 10 m2/g.
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