- THE DIMESITYLBORON GROUP IN ORGANIC SYNTHESIS 2. THE C-ALKYLATION OF ALKYLDIMESITYLBORANES
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It is demonstrated that anions α to the dimesitylboron group are alkylated at carbon in excellent yields.The alkylations may be repeated, so allowing for one-pot, one, two or three insertion reactions.
- Pelter, Andrew,Williams, Lorraine,Wilson, John W.
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- Hydrocarbonylation reactions using alkylphosphine-containing dendrimers based on a polyhedral oligosilsesquioxane core
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Radical additions of HPR2 (R = Et, Cy) onto alkenyl groups or nucleophilic substitution reactions on chlorosilanes by LiCH2PR2 (R = Me, Hex) are used to prepare first and second-generation alkylphosphine-containing dendrimers based on a polyhedral oligomeric silsesquioxane (POSS) core. The first generation dendrimers (G1) are built on 16 or 24 arms, which are chlorides, vinyl groups or allyl moieties. Hydrosilylation (chlorosilane) followed by vinylation or allylation of octavinyl-functionalised POSS gave these G1 dendrimers. Successive hydrosilylation/allylation followed by hydrosilylation/vinylation produce the framework for the second-generation dendrimer (G2). The phosphorus-containing dendrimers are used as ligands for the hydrocarbonylation of alkenes (hex-1-ene, oct-1-ene, non-1-ene, prop-1-en-2-ol) in polar solvents (ethanol or THF) using the complexes [Rh(acac)(CO)2] or [Rh2(O2CMe)4] as metal source. Linear to branched ratios up to 3:1 for the alcohol products are obtained for the diethylphosphine dendrimers. The reactions were found to proceed mainly via the formation of the corresponding aldehydes.
- Ropartz, Loic,Foster, Douglas F.,Morris, Russell E.,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
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- Selective aldehyde reduction in ketoaldehydes with NaBH4-Na 2CO3-H2O at room temperatures
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A variety of aliphatic and aromatic ketoaldehydes were reduced to the corresponding ketoalcohols with a mixture of sodium borohydride (1.2 equivalents) and sodium carbonate (sixfold molar excess) in water. Reactions were performed at room temperatures(typically) 2 h, and yields of isolated products generally ranged from 70% to 85%. A bis-carbonate-borane complex, [(BH3)2CO2]2- 2Na+, possibly formed from the reagent mixture, is likely the active reductant. The moderated reactivity of this acylborane species would explain the chemoselectivity observed in the reactions. The readily available reagents and the mild aqueous conditions make for ease of operation and environmental compatibility, and make a useful addition to available methodology. Copyright
- Chandrasekhar, Sosale,Shrinidhi, Annadka
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- Anomalous Rapid Reduction of Salicylaldehyde by Pyridine-Borane. Mechanism and Application to Selective Aldehyde Reduction
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The reduction of salicylaldehyde by pyridine-borane complex (PB) is much faster than that of other substituted benzaldehydes and ketones (seconds vs hours).Experiments reveal that this acceleration is due to an autocatalytic process involving a pyridinium boronate salt, a component of the equilibrating product mixture from PB reduction of salicylaldehyde.This pyridinium salt behaves as a mild Broensted acid and effectively accelerates aldehyde but not ketone reductions by PB.The observation that mild Broensted acids are catalysts for PB reductions led to the development of a method using AcOH in CH2Cl2 to promote the selective reduction of aldehydes in the presence of ketones.
- Chen, Joseph,Wayman, Kjirsten A.,Belshe, Marie A.,DiMare, Marcello
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- Copper-Catalyzed Borylative Methylation of Alkyl Iodides with CO as the C1 Source: Advantaged by Faster Reaction of CuH over CuBpin
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CuH and CuBpin are versatile catalysts and intermediates in organic chemistry. However, studies that involve both CuH and CuBpin in the same reaction is still rarely reported due to their high reactivity. Now, a study on CuH- and CuBpin-catalyzed borylative methylation of alkyl iodides with CO as the C1 source is reported. Various one carbon prolongated alkyl boranes (RCH2Bpin and RCH(Bpin)2) were produced in moderate to good yields from the corresponding alkyl iodides (RI). In this cooperative system, CuH reacts with alkyl iodide faster than CuBpin.
- Wu, Fu-Peng,Wu, Xiao-Feng
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- Kolbe Electrolysis of Biomass-Derived Fatty Acids Over Pt Nanocrystals in an Electrochemical Cell
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Electrochemical valorization of non-food biomass-derived carboxylates into fuels is promising for the conversion, storage, and distribution of renewable electricity. Herein, we demonstrate that biofuels, hydrogen, and bicarbonate can be simultaneously produced in an electrochemical cell by one-step electrolysis of free fatty acids under ambient conditions on 3D self-supported ultralow Pt loading (2 wt %) electrode. The three valuable products can naturally separate from each other during the electrolysis in the alkaline aqueous solution. The experimental suggests that Pt(100) and Pt(110) are favorable for the production of non-Kolbe and Kolbe hydrocarbons, respectively. DFT calculation further clarifies the adsorption and stabilization of the reaction intermediates on Pt(100) and Pt(110).
- Yuan, Gang,Wu, Chan,Zeng, Guorong,Niu, Xiaopo,Shen, Guoqiang,Wang, Li,Zhang, Xiangwen,Luque, Rafael,Wang, Qingfa
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- Catalytic Reactions of Metalloporphyrins. 3. Catalytic Modification of Hydroboration-Oxidation of Olefin with Rhodium(III) Porphyrin as Catalyst
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(Octaethylporphyrinato)- or (tetraphenylporphyrinato)rhodium(III) chloride catalyzes the anti-Marcovnikov "hydration" of olefin with NaBH4 and O2 in THF. 1,5-Cyclooctadiene gives rise to cyclooctanol and 1,5-cyclooctanediol (in a ratio of approximately 1:2), and acetylenes are converted directly to alcohols under similar conditions.The initial step in the catalytic reaction of olefin is the hydride and borane transfers from BH4- respectively to RhIII porphyrin and olefin to give hydridorhodium (RhH) porphyrin and alkylborane.The RhH species undergoesoxidation with O2 back to RhIII with concomitant oxidation of alkylborane with retention of configuration.This coupled oxidation of alkylborane is in competition with its nonstereospecific autooxidation without assistance of Rh-H.The present system provides a catalytic modification of hydroboration-oxidation of olefin in the presence of oxygen, as illustrated by the one-pot conversion of 1-methylcyclohexene to (E)-2-methylcyclohexanol with 100 percent regioselectivity and up to 97 percent stereoselectivity.
- Aoyama, Yasuhiro,Tanaka, Yasutaka,Fujisawa, Takeshi,Watanabe, Takamichi,Toi, Hiroo,Ogoshi, Hisanobu
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- BEHAVIOR OF AMINE IN RHODIUM COMPLEX-TERTIARY AMINE CATALYST SYSTEM ACTIVE FOR HYDROGENATION OF ALDEHYDE UNDER OXO REACTION CONDITIONS.
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The reaction was investigated to elucidate the reported disagreements on the kinetics. The concentration and the coordination stability of amine were found to affect the optimum pressure of carbon monoxide and the kinetics, and were suggested to control the reaction mechanism.
- Mizoroki,Kioka,Suzuki,Sakatani,Okumura,Maruya
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- Highly efficient, general hydrogenation of aldehydes catalyzed by PNP iron pincer complexes
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A general protocol for the synthetically and industrially important hydrogenation of aldehydes to alcohols is reported. The reactions are catalyzed by well-defined iron pincer complexes that are capable of hydrogenation of aliphatic and aromatic aldehydes selectively and efficiently under mild conditions, with unprecedented turnover numbers.
- Zell, Thomas,Ben-David, Yehoshoa,Milstein, David
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- Formate reduction of aldehydes using a photogenerated chromium carbonyl catalyst
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The aldehydes RCHO (R = p-tolyl, p-anysil, n-hexyl) are reduced to the corresponding alcohols RCH2OH by sodium formate in 95percent aqueous methanol in the presence of a catalyst photogenerated from Cr(CO)6.
- Linn, D. E.,King, R. B.,King, A. D.
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- Heptanuclear Fe5Cu2-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C-H Compounds
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A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO2)12Cu2Fe5(O)OH(PhGe)2O5(bipy)2 (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO2)12 and acyclic (Ph2Ge2O5) germoxanolates and (ii) O2- and (iii) HO- moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2′-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).
- Bilyachenko, Alexey N.,Khrustalev, Victor N.,Zubavichus, Yan V.,Shul'Pina, Lidia S.,Kulakova, Alena N.,Bantreil, Xavier,Lamaty, Frédéric,Levitsky, Mikhail M.,Gutsul, Evgeniy I.,Shubina, Elena S.,Shul'Pin, Georgiy B.
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- Carbonyl reductase activity exhibited by pig testicular 20β- hydroxysteroid dehydrogenase
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The carbonyl reductase activity exhibited by pig testicular 20β- hydroxysteroid dehydrogenase (20β-HSD) was examined using a recombinant enzyme. Kinetic parameters were obtained for 48 carbonyl group-containing substrates, including aromatic aldehydes, aromatic ketones, cycloketones, quinones, aliphatic aldehydes and aliphatic ketones. 20β-HSD showed a high affinity towards quinones, such as 9,10-phenanthrenequinone, α- naphthoquinone and menadione (K(m) values of 4, 2 and 5 μM, respectively), and the substrate utilization efficiency (V(max)/K(m)) of the enzyme against these quinones was very high. Cyclohexanone and 2-methylcyclohexanone were also reduced with a high V(max)/K(m) value, but not cyclopentanone or 2- methylcyclopentanone. Various aromatic aldehydes and ketones including benzaldehyde- and acetophenone-derivatives were reduced by 20β-HSD. Especially, 4-nitrobenzaldehyde and 4-nitroacetophenone were reduced with high V(max)/K(m) values in the related compounds. The enzyme also reduced the pyridine-derivatives, 2-, 3-, and 4-benzoylpyridine, with the V(max)/K(m) value for 2-benzoylpyridine being the highest. 20β-HSD reduced aliphatic aldehydes and aliphatic ketones, but was more effective on the former. The correlation between the structure of carbonyl compounds and their substrate V(max)/K(m) is discussed.
- Nakajin, Shizuo,Tamura, Fumihiro,Takase, Noriko,Toyoshima, Satoshi
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- Shape-selective Alkane Hydroxylation
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A series of sterically hindered manganese porphyrins have been used to catalyse shape-selective alkane hydroxylation, increasing the production of primary alcohols.
- Suslick, Kenneth,Cook, Bruce,Fox, Mary
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- Synthesis characterization and hydroformylation activity of new mononuclear rhodium(I) compounds incorporated with polar-group functionalized phosphines
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A first effort employing a range of polar-group functionalized phosphines (L1-L7) to design mononuclear Rh(I) compounds of [Rh(quin-8-O)(CO)(L)] (quin-8-O = 8-hydroxy quinolate) is described. The reaction of a Rh(I) precursor [Rh(μ-Cl)(CO)2]2 with 8-hydroxyquinoline in the presence of a base followed by phosphines (L1-L7) produced only a single isomer of [Rh(quin-8-O)(CO)(L)] compounds (1-7) with pendant, i.e. non-bonded, polar-groups (includes carboxyl, hydroxyl and formyl). A relationship between Δgd31P chemical shifts and the ν(C≡O) was derived to evaluate and explain the σ-donor properties of these phosphines with respect to the electronic properties of the polar groups and the extent of π-back-bonding to the CO group. These mononuclear Rh(I)-Phosphines were investigated as catalysts in the hydroformylation of 1-hexene and cyclohexene in aqueous two-phase and single-phase solvent systems. The Rh(I) catalysts with strong σ-donor and hydrophilic phosphines provided better yields and selectivities for the hydroformylation products, which is a reverse trend compared to literature reports. When the Rh(I) compounds contained strong σ-donor phosphines, the π-acceptor properties of the pyridine ring of 8-hydroxyquinolate were found to be beneficial for the facile cleavage of the CO group during hydroformylation, and additionally, to improve the kinetic stability of catalysts. Versita Warsaw and Springer-Verlag Berlin Heidelberg.
- Vasam, Chandra S.,Modem, Sarangapani,Kankala, Shravankumar,Kanne, Shanker,Budige, Geeta,Vadde, Ravinder
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- Efficient deprotection of tetrahydropyranyl ethers by bismuth(III) salts
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Treatment of tetrahydropyranyl(THP) ethers with bismuth(III) salts including BiC13, Bi(TFA)3 and Bi(OTf)3 in methanol provides a simple and efficient process for deprotection of these ethers and the parent alcohols were obtained in excellent yields.
- Mohammadpoor-Baltork, Iraj,Kharamesh, Bahram,Kolagar, Sadegh
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- An efficient catalytic approach for the synthesis of unsymmetrical siloxanes
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The potential for expanding the variety of catalytic methods for siloxane bond formation is explored. Alkoxysilanes react with methylallylsilanes in the presence of scandium(III) trifluoromethanesulfonate to yield disiloxanes and isobutene. The reaction p
- Hreczycho, Grzegorz
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- Interplay between Substrate and Proton Donor Coordination in Reductions of Carbonyls by SmI2-Water Through Proton-Coupled Electron-Transfer
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The reduction of a carbonyl by SmI2-water is the first step in a range of reactions of synthetic importance. Although the reduction is often proposed to proceed through an initial stepwise electron-transfer-proton-transfer (ET-PT), recent work has shown that carbonyls and related functional groups are likely reduced though proton-coupled electron-transfer (PCET). In the present work, the reduction of an activated ester, aldehyde, a linear and cyclic ketone, and related sterically demanding carbonyls by SmI2-H2O was examined through a series of mechanistic experiments. Kinetic studies demonstrate that all substrates exhibit significant increases in the rate of reduction by SmI2 as [H2O] is increased. Under identical conditions, ketones and an aldehyde containing a methyl adjacent to the carbonyl are reduced slower than an unsubstituted variant by an order of magnitude, demonstrating the importance of substrate coordination. In the case of unactivated substrates, rates of reduction show excellent correlation with the calculated bond dissociation free energy of the O-H bond of the intermediate ketyl and the calculated free energy of intermediate ketyl radical anions derived from unhindered substrates: findings consistent with concerted PCET. Activated esters derived from methylbenzoate are likely reduced through stepwise or asynchronous PCET. Overall, this work demonstrates that the combination of the coordination of substrate and water to Sm(II) provides a configuration uniquely suited to a coupled electron- and proton-transfer process.
- Chciuk, Tesia V.,Anderson, William R.,Flowers, Robert A.
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- INSECT PHEROMONES AND THEIR ANALOGS III. SYNTHESIS OF THE SEX ATTRACTANTS OF SOME LEPIDOPTERA
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A new route to the synthesis of a number of attractants of Lepidoptera (Argyrotaenia velutinana, Mamestra configurata, and Lycorea ceres ceres) have been developed.These substances are acetates of enols with the cis configuration: tetradec-11-en-1-ol, hexadec-11-en-1-ol, and octadec-11-en-1-ol, respectively.The constants of the substances obtained agree completely with those given in the literature.The method is based on the coupling of the C3, C5, and C7 aldehydes with methyl 11-bromoundecanoate (I) by the Wittig reaction.To obtain compound (I) from methyl undeca-2E,5E,10-trienoate or methyl undeca-10-enoate we used hydroboration according to Brown followed by hydrogenation and bromination of the alcohol obtained.The advantage of this method is the use as starting materials of esters of unsaturated acids readily obtained by the homogeneous catalytic co-oligomerization of 1,3-dienes with acrylates.
- Dzhemilev, U. M.,Balezina, G. G.,Volkova, L. A.,Krivonogov, V. P.,Tolstikov, G. A.
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- Highly efficient transfer hydrogenation of aldehydes and ketones using potassium formate over AlO(OH)-entrapped ruthenium catalysts
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Ruthenium encapsulated in an aluminium oxyhydroxide-support was investigated for the transfer hydrogenation of aldehydes and ketones with potassium formate as a sustainable green hydrogen donor. The entrapped ruthenium were narrowly distributed with mean diameters of 1.5-1.8 nm. XPS studies show that the ruthenium was present as Ru0 and Ru3+. The catalysts showed high activity even at low metal loadings of 0.5-2 wt.%. The maximum TOF for benzaldehyde hydrogenation was over 1 wt.% Ru. The reduction of aromatic and aliphatic aldehydes was facile and occurred with 100% yield. In comparison, ketones were less readily reduced although moderate to excellent yields could be obtained after a longer reaction time. No leaching of ruthenium was observed in contrast to a catalyst prepared by wet impregnation. Washing of the used catalyst with water and ethanol effectively removed the deposited bicarbonate co-product and the recycled catalyst maintained its activity up to five runs.
- Gao, Yanxiu,Jaenicke, Stephan,Chuah, Gaik-Khuan
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- Catalytic carbonyl hydrosilylations: Via a titanocene borohydride-PMHS reagent system
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Reduction of a wide range of aldehydes and ketones with catalytic amounts of titanocene borohydride in concert with a stoichiometric poly(methylhydrosiloxane) (PMHS) reductant is reported. Preliminary mechanistic studies demonstrate that the reaction is mediated by a reactive titanocene(iii) complex, whose oxidation state remains constant throughout the reaction.
- Fianu, Godfred D.,Schipper, Kyle C.,Flowers, Robert A.
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- Water-soluble, 1,3,5-Triaza-7-phosphaadamantane-stabilized palladium nanoparticles and their application in biphasic catalytic hydrogenations at room temperature
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Water-dispersible Pd nanoparticles stabilized by the hydrophilic cage-like aminophosphine ligand 1,3,5-triaza-7-phosphaadamantane and its N-methyl derivative were synthesized and fully characterized in the colloidal state by TEM, and NMR and UV spectroscopy and in the solid state by X-ray photoelectron spectroscopy and powder XRD. The three different nanoparticles obtained showed a narrow distribution range with average core sizes of 2.8, 3.2, and 3.5nm. The activity of some of these Pd nanoparticles as catalysts in the biphasic hydrogenation of organic substrates under mild conditions has been tested, and good results and excellent reusability (up to nine catalytic runs) were obtained.
- Caporali, Maria,Guerriero, Antonella,Ienco, Andrea,Caporali, Stefano,Peruzzini, Maurizio,Gonsalvi, Luca
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- Rapid aqueous borohydride reduction of carbonyls under sealed-tube microwave conditions
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Ketones and aldehydes are conveniently and rapidly reduced to the corresponding alcohols in good yields using sodium borohydride under sealed-tube microwave conditions in either 95% ethanol or water. In purely aqueous systems, highly aliphatic substrates are sluggish, but this can be overcome by introducing sodium dodecyl sulfate (SDS) at the critical micelle concentration. With a 2:1 substrate/borohydride ratio and a reaction temperature of 100°C, reduction is typically complete within 1min in 95% ethanol and 5min in water/SDS. The methodology is well suited for parallel and combinatorial synthetic approaches.
- Murphree, S. Shaun,Mason, Jeremy D.,Bean, Theodore G.,Perry, Michelle C.
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- Regioselective C-H hydroxylation of: N -alkanes using Shilov-type Pt catalysis in perfluorinated micro-emulsions
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Shilov-chemistry inspired catalysis has remained largely overlooked as a tool for establishing the remote hydroxylation of non-polar compounds, such as long linear alkanes, due to the need for an acidic aqueous solution. To circumvent the solubility issue, the concept of micellar catalysis is introduced, using PtII in perfluorinated micro-emulsions. Notably, the terminal C-H activation of n-heptane is demonstrated under an oxygen atmosphere using perfluorooctanoic acid (PFOA) as a surfactant, along with the intrinsic ability of PtII to convert the highly inert primary C-H bonds. Coordination of PtII to the carboxylate groups of PFOA proved to be particularly important for achieving maximum catalyst activity towards the hydrocarbon substrate solubilized inside the micelle interior. Based on these insights, optimization of the reaction parameters allowed a positional selectivity of 60% for 1-heptanol, among the C7 alcohols, to be achieved, using low catalyst and surfactant loadings under acid-free conditions.
- De Vos, Dirk E.,Janssen, Michiel
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- Alkyl Formate Ester Synthesis by a Fungal Baeyer–Villiger Monooxygenase
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We investigated Baeyer–Villiger monooxygenase (BVMO)-mediated synthesis of alkyl formate esters, which are important flavor and fragrance products. A recombinant fungal BVMO from Aspergillus flavus was found to transform a selection of aliphatic aldehydes into alkyl formates with high regioselectivity. Near complete conversion of 10 mm octanal was achieved within 8 h with a regiomeric excess of ～80 %. Substrate concentration was found to affect specific activity and regioselectivity of the BVMO, as well as the rate of product autohydrolysis to the primary alcohol. More than 80 % conversion of 50 mm octanal was reached after 72 h (TTN nearly 20 000). Biotransformation on a 200 mL scale under unoptimized conditions gave a space-time yield (STY) of 4.2 g L?1 d?1 (3.4 g L?1 d?1 extracted product).
- Ferroni, Felix Martin,Tolmie, Carmien,Smit, Martha Sophia,Opperman, Diederik Johannes
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- Improved regioselectivity in the hydroformylation reaction catalysed by zeolite-encapsulated rhodium(I) species
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Although zeolite-encapsulated [Rh(CO)x(PR3)y] (PR3 = PEt3, PEt2Ph, PPrn3 or PPh3) give similar chemoselectivities in the hydrocarbonylation of hex-1-ene relative to their homogeneous analogues, the linear : branched ratio can be increased by as much as 10 times.
- Andersen, Jo-Ann M.,Currie, Alan W. S.
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- One-pot synthesis of alcohols from olefins catalyzed by rhodium and ruthenium complexes
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The one-pot synthesis of butanol and heptanol from propene and 1-hexene, respectively, was performed using Ru3(PPh3)Cl2 and Rh(CO)2(acac) in the presence of triphenylphosphene. The effects of various reaction parameters, including catalyst concentration, gas partial pressures, and temperature, were investigated. Two methods for performing the one-pot synthesis were developed and are discussed. In the first method, stoichiometric quantities of CO and propene or 1-hexene were fed to the autoclave. It was found that residual carbon monoxide necessary for the hydroformylation poisoned the Ru catalyst used for the hydrogenation. Venting the hydroformylation gases was therefore necessary for hydrogenation of the aldehyde to proceed. In the second method, sub-stoichiometric quantities of CO relative to olefin were fed to the autoclave, and CO conversion was driven to nearly 100%. In this case, the low residual CO concentration allowed the hydrogenation to proceed readily. The optimal temperatures and gas pressures for the hydroformylation were not the optimal temperatures and pressures for the hydrogenation. A strategy is described for maximizing the performance of both steps. Under optimal conditions, 100% conversion of propene to butanol could be achieved with 97% selectivity, and 99% conversion of 1-hexene to hepatanol could be achieved with 98% selectivity. The only byproduct observed in the latter case was a small amount of 2-hexene, which did not undergo hydroformylation. A possible reaction mechanism is proposed for both the hydroformylation of the olefin and the hydrogenation of aldehyde based on spectroscopic evidence.
- Zakzeski, Joseph,Lee, Hae Ryun,Leung, Yi Ling,Bell, Alexis T.
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- Oxidation of hydrocarbons with tetra-n-butylammonium peroxy monosulfate catalyzed by β-tetrabromo-meso-tetrakis(4-methoxyphenyl)-and β-tetrabromo-meso-tetraphenylporphyrinatomanganese(III)
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β-Tetrabromo-meso-tetrakis(4-methoxyphenyl)porphyrin, H2 T(4-OCH3 P)PBr4, was synthesized and characterized by UV-Vis and 1H NMR spectroscopy. Oxidation of alkanes and olefins with tetra-n-butylammonium peroxymonosulfate (n-Bu4NHSO5) was studied in the presence of MnT(4-OCH3 P)PBr4 (OAc) and MnTPPPBr4 (OAc) (TPP = meso-tetraphenylporphyrin). While significance differences were observed between the catalytic activities of the title complexes in the oxidation of alkanes, the 2 manganese porphyrins showed comparable activities in oxidation of most of the olefins used. However, the latter showed greater catalytic performance in the oxidation of the hydrocarbons. Moreover, the oxidative degradation of the former (60%) was greater than that of the latter (45%) in the oxidation of cyclooctene. TUeBITAK.
- Rayati, Saeed,Zakavi, Saeed,Valinejad, Hossein
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- Cp2TiCl2-CATALYZED GRIGNARD REACTIONS. 3. REACTIONS WITH ESTERS: EFFICIENT METHODOLOGY FOR THE SYNTHESIS OF SECONDARY ALCOHOLS AND FOR THE REDUCTION OF ESTERS TO PRIMARY ALCOHOLS
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Cp2TiCl2-catalyzed Grignard reactions with esters provide general methodology for preparation of secondary alcohols or for reduction of esters to the corresponding primary alcohols.
- Sato, Fumie,Jinbo, Takamasa,Sato, Masao
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- Selective Hydrogenation of Crotonaldehyde to Crotyl Alcohol over Metal Oxide Modified Ir Catalysts and Mechanistic Insight
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The scope of metal oxide modified noble metal (M+M′Ox) catalysts was scrutinized in the hydrogenation of crotonaldehyde to crotyl alcohol as a model reaction under mild reaction conditions (303 K, 0.8 MPa, water solvent), demonstrating that MoOx, WOx, NbOx, FeOx and ReOx are effective metal oxides for Ir/SiO2 to enhance both the activity and selectivity, although the optimized (metal oxide)/(Ir metal) molar ratio depends on the metal oxide. MoOx modified Ir/SiO2 catalyst (Ir-MoOx/SiO2 (Mo/Ir = 1)) was the most efficient, providing a high yield of crotyl alcohol (90%) and a high TOF (217 h-1). The catalytic activity under such mild reaction conditions is the highest among the reported heterogeneous catalysts. These results showed that modification of active metals with an appropriate amount of metal oxides is an effective method for the development of efficient catalysts for selective hydrogenations. The reaction mechanism over the metal oxide modified Ir catalysts was investigated using Ir-ReOx/SiO2 (Re/Ir = 1) as a model catalyst by means of FTIR studies on H2/D2 adsorption, crotonaldehyde adsorption, and temperature-programmed desorption of crotonaldehyde, and kinetic studies on effects of H2 pressure and crotonaldehyde concentration, isotopic effect of hydrogen (VH2/VD2), and comparison of reactivities between the aldehyde group and olefin group using various substrates. The reaction proceeds via four steps: (i) adsorption of crotonaldehyde on ReOx species, (ii) generation of hydride species from H2 on Ir metal species, (iii) hydride attack to the crotonaldehyde adspecies, and (iv) desorption of the produced crotyl alcohol, and the third step is the rate-determining step. Ir metal plays a role in the generation of hydride (H-) species from H2, leading to the high selectivity to crotyl alcohol, and ReOx plays a role in promotion of crotonaldehyde adsorption, leading to the proximity of crotonaldehyde to the active site and activation of the aldehyde group, which results in high activity and further improvement in the selectivity.
- Tamura, Masazumi,Tokonami, Kensuke,Nakagawa, Yoshinao,Tomishige, Keiichi
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- Miniaturizing biocatalysis: Enzyme-catalyzed reactions in an aqueous/organic segmented flow capillary microreactor
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A segmented flow capillary microreactor was used to perform the enzyme-catalyzed conversion of 1-heptaldehyde to 1-heptanol in a two liquid-liquid phase system. These reactor formats are established for chemical reactions but so far data describing the relevant system parameters for enzymatic catalysis are lacking. This work now addresses the impact of important parameters such as capillary diameter, flow velocity, phase ratio, and enzyme as well as substrate concentration on the performance of the enzymatic reaction under segmented flow conditions. All key parameters governing reaction performance have been correlated in a novel operational window for an easy assessment of the various system constraints. Such systems are characterized by high productivities and easy phase separation facilitating downstream processing. This work underscores the importance of segmented flow systems as a promising tool to perform multiphasic enzymatic catalysis. Abbreviations/ Nomenclature: Da: Damkoehler number; kcat: turnover number (s-1); eo: enzyme concentration (mM); I?: phase ratio; kL: mass transfer coefficient (m s-1); a: interfacial area per volume (m-1); CAe: equilibrium substrate concentration in the aqueous phase (mM); CAL: substrate concentration in the bulk aqueous phase (mM); rA: rate of reaction in the aqueous phase; mA: substrate mass transfer into the aqueous phase; STY: space time yield. Copyright
- Karande, Rohan,Schmid, Andreas,Buehler, Katja
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- SELECTIVE CYCLOALKANONE REDUCTIONS USING ALUMINUM AMALGAM
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Aluminum amalgam in aqueous tetrahydrofuran reduces cycloalkanones to their respective alcohols.The reaction exhibits sensitivity to the ring size and steric environment of the ketone.
- Hulce, Martin,LaVaute, Timothy
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- Carbon–Carbon Bond Formation and Hydrogen Production in the Ketonization of Aldehydes
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Aldehydes possess relatively high chemical energy, which is the driving force for disproportionation reactions such as Cannizzaro and Tishchenko reactions. Generally, this energy is wasted if aldehydes are transformed into carboxylic acids with a sacrificial oxidant. Here, we describe a cascade reaction in which the surplus energy of the transformation is liberated as molecular hydrogen for the oxidation of heptanal to heptanoic acid by water, and the carboxylic acid is transformed into potentially industrially relevant symmetrical ketones by ketonic decarboxylation. The cascade reaction is catalyzed by monoclinic zirconium oxide (m-ZrO2). The reaction mechanism has been studied through cross-coupling experiments between different aldehydes and acids, and the final symmetrical ketones are formed by a reaction pathway that involves the previously formed carboxylic acids. Isotopic studies indicate that the carboxylic acid can be formed by a hydride shift from the adsorbed aldehyde on the metal oxide surface in the absence of noble metals.
- Orozco, Lina M.,Renz, Michael,Corma, Avelino
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- Aluminium isopropoxide - TFA, a modified catalyst for highly accelerated Meerwein-Ponndorf-Verley (MPV) reduction
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Aldehydes and ketones have been reduced very rapidly in good yields at room temperature by addition of trifluoroacetic acid (TFA) to aluminium isopropoxide (AIP) in MPV reduction.
- Akamanchi,Varalakshmy
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- Direct formation of alcohols by hydrocarbonylation of alkenes under mild conditions using rhodium trialkylphosphine catalysts
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The complex [RhH(PEt3)3] catalysed the hydroformylation of hex-1-ene to heptanal and 2-methylhexanal in toluene, but heptanol and 2-methylhexanol were significant products in tetrahydrofuran especially over long reaction times (16 h). In protic solvents only alcohols were produced even after short reaction times. The reactions are very rapid and also occur readily with alkenes such as hex-2-ene, propene, ethene, styrene and 3,3-dimethylbutene. The highest rates observed are for ethene (54 000 turnovers h-1) and the products in all cases are alcohols. Other phosphines containing primary alkyl groups also produced alcohols, but in contrast reactions in ethanol using rhodium complexes containing PPh3, PPh2Et, PPhEt2 or PPri3 produced significant amounts of aldehydes and/or acetals whilst Me2PCH2CH2PMe2 inhibited the reaction. The NMR studies showed that species present in equilibrium in ethanol solution are [RhH(CO)(PEt3)3], [RhH(CO)2(PEt3)2], [Rh2(CO)4(PEt3)4], [Rh2(CO)2(PEt3)6] and PEt3 but that [RhH(CO)(PEt3)3] predominates under the catalytic conditions. Reactions carried out under D2-CO in EtOH produced 90% BuCHDCH2CD2OH/D and 10% BuCHDCH2CHDOH/D but hydrogenation of heptanal under the same conditions gave a mixture of C6H13CHDOH/D (39%) and C6H13CH2OH/D (61%). These results are interpreted to indicate that the alcohols produced from hex-1-ene are primary reaction products and not produced via intermediate aldehydes. A new mechanism for this direct hydrocarbonylation is proposed in which the key acyl intermediate becomes protonated by the alcoholic solvent because of the high electron density it bears as a result of the presence of the electron-donating trialkylphosphines. Oxidative addition of H2 followed by two H-atom transfers leads directly to the alcohol. High pressure NMR studies showed that [Rh{C(O...HOEt)Et}(CO)2(PEt3)2] is present during catalytic hydrocarbonylation of ethene in ethanol. Two different cycles are proposed to explain the products obtained from the catalytic reaction of heptanal with D2-CO. Again, protonation, this time of the metal, appears to be important.
- MacDougall, Joanna K.,Simpson, Michael C.,Green, Michael J.,Cole-Hamilton, David J.
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- The selective reduction of aldehydes using polyethylene glycol-sodium borohydride derivatives as phase transfer reagents
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A phase transfer reagent derived from PEG-sodium borohydride was developed which controlled both the activity and the amount of the reagent in the organic phase. Using this reagent under solid-liquid phase transfer conditions, it was found that aldehydes could be selectively reduced in the presence of ketones without concurrent reduction of the ketone group. The reactions were conducted at room temperature and were generally complete within two hours.
- Blanton, James R.
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- Direct Formation of Alcohols in Homogeneous Hydroformylation catalysed by Rhodium Complexes
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Hydroformylation of hex-1-ene catalysed by or /PR3, R = Me, Et, or Bu, produces a mixture of aldehydes and alcohols in toluene or tetrahydrofuran but exclusively alcohols in ethanol; or produce mainly aldehydes or acetals when ethanol is used as the solvent.
- MacDougall, Joanna K.,Cole-Hamilton, David J.
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- Rapid reduction of carbonyls with nickel boride at ambient utemperature
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Carbonyl compounds have been reported to undergo rapid reduction with nickel boride generated in situ from anhyd. nickel chloride and sodium borohydride in THF at ambient temperature to the corresponding alcohols in high yields.
- Khurana,Chauhan
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- Alkylation of Pentaerythritol and Trimethylolpropane, Two Very Hydrophilic Polyols, by Phase-Transfer Catalysis.
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Two very hydrophilic polyols, pentaerythritol and trimethylolpropane , can be etherified in good yields by phase-transfer catalysis with allyl chloride or heptyl bromide as alkylating agents.Ion pairs solubilities, lipophilicities of catalysts, and nature of the reaction products which are key factors in achievement of this PTC reaction are discussed.
- Nouguier, R. M.,Mchich, M.
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- Hydroformylation of alkenes in supercritical carbon dioxide catalysed by rhodium trialkylphosphine complexes
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Rhodium complexes modified by simple trialkylphosphines can be used to carry out homogeneous hydroformylation in supercritical carbon dioxide (scCO2). The catalyst derived from PEt3 is more active and slightly more selective for the linear products in scCO2 than in toluene, and under the same reaction conditions [100°C, 40 bar of CO/H2 (1:1)] P(OPri)3 is also an effective ligand giving good catalyst solubility and activity. Other ligands such as PPh3, POct3, PCy3, and P(4-C6H4But)3 are less effective because of the low solubility of their rhodium complexes in scCO2. P(4-C6H4SiM3),Ph3-n, (n = 3 or 1) and P(OPh)3 impart activity despite their complexes only being poorly soluble in scCO2. Under subcritical conditions, using PEt3 as the ligand, C7-alcohols from hydrogenation of the first formed aldehydes are the main products whilst above a total pressure of 200 bar, where the solution remains supercritical (monophasic) throughout the reaction, aldehydes are obtained with 97% selectivity. High pressure IR studies in scCO2 using PEt3 as the ligand are reported.
- Sellin, Murielle F.,Bach, Ingrid,Webster, Jeremy M.,Montilla, Francisco,Rosa, Vitor,Aviles, Teresa,Poliakoff, Martyn,Cole-Hamilton, David J.
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- Hydrogenation of n-heptanal, catalyzed by cobalt carbonyl phosphine complex
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The use of the cobalt carbonyl phosphine complex Co2(CO)6(PR3)2 (R = C4H9) as catalyst precursor allows synthesis of n-heptanol from n-heptanal to be performed with high selectivity.
- Krylova,Vigranenko,Kocheregin
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- Oxygen Atom Transfer Mechanism for Vanadium-Oxo Porphyrin Complexes Mediated Aerobic Olefin Epoxidation
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The development of catalytic aerobic epoxidation by numerous metal complexes in the presence of aldehyde as a sacrificial reductant (Mukaiyama epoxidation) has been reported, however, comprehensive examination of oxygen atom transfer mechanism involving free radical and highly reactive intermediates has yet to be presented. Herein, meso-tetrakis(pentafluorophenyl) porphyrinatooxidovanadium(IV) (VOTPFPP) was prepared and proved to be efficient toward aerobic olefin epoxidation in the presence of isobutyraldehyde. In situ electron paramagnetic resonance spectroscopy (in situ EPR) showed the generation, transfer pathways and ascription of free radicals in the epoxidation. According to the spectral and computational studies, the side-on vanadium-peroxo complexes are considered as the active intermediate species in the reaction process. In the cyclohexene epoxidation catalyzed by VOTPFPP, the kinetic isotope effect value of 1.0 was obtained, indicating that epoxidation occurred via oxygen atom transfer mechanism. The mechanism was further elucidated using isotopically labeled dioxygen experiments and density functional theory (DFT) calculations.
- Han, Qi,Huang, Jia-Ying,Ji, Hong-Bing,Liu, Xiao-Hui,Tao, Lei-Ming,Xue, Can,Yu, Hai-Yang,Zhou, Xian-Tai,Zou, Wen
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supporting information
p. 115 - 122
(2021/12/04)
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- Directing Selectivity to Aldehydes, Alcohols, or Esters with Diphobane Ligands in Pd-Catalyzed Alkene Carbonylations
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Phenylene-bridged diphobane ligands with different substituents (CF3, H, OMe, (OMe)2, tBu) have been synthesized and applied as ligands in palladium-catalyzed carbonylation reactions of various alkenes. The performance of these ligands in terms of selectivity in hydroformylation versus alkoxycarbonylation has been studied using 1-hexene, 1-octene, and methyl pentenoates as substrates, and the results have been compared with the ethylene-bridged diphobane ligand (BCOPE). Hydroformylation of 1-octene in the protic solvent 2-ethyl hexanol results in a competition between hydroformylation and alkoxycarbonylation, whereby the phenylene-bridged ligands, in particular, the trifluoromethylphenylene-bridged diphobane L1 with an electron-withdrawing substituent, lead to ester products via alkoxycarbonylation, whereas BCOPE gives predominantly alcohol products (n-nonanol and isomers) via reductive hydroformylation. The preference of BCOPE for reductive hydroformylation is also seen in the hydroformylation of 1-hexene in diglyme as the solvent, producing heptanol as the major product, whereas phenylene-bridged ligands show much lower activities in this case. The phenylene-bridged ligands show excellent performance in the methoxycarbonylation of 1-octene to methyl nonanoate, significantly better than BCOPE, the opposite trend seen in hydroformylation activity with these ligands. Studies on the hydroformylation of functionalized alkenes such as 4-methyl pentenoate with phenylene-bridged ligands versus BCOPE showed that also in this case, BCOPE directs product selectivity toward alcohols, while phenylene-bridge diphobane L2 favors aldehyde formation. In addition to ligand effects, product selectivities are also determined by the nature and the amount of the acid cocatalyst used, which can affect substrate and aldehyde hydrogenation as well as double bond isomerization.
- Aitipamula, Srinivasulu,Britovsek, George J. P.,Nobbs, James D.,Tay, Dillon W. P.,Van Meurs, Martin
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p. 1914 - 1925
(2021/06/28)
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- Interworking ligand, hydroformylation catalyst and preparation method of dihydric alcohol
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The invention discloses an interworking ligand, a hydroformylation catalyst and a preparation method of dihydric alcohol. The interworking ligand comprises a ligand unit I and a ligand unit II, has the characteristics of a bidentate phosphine ligand, and is high in catalytic activity and good in stability; and when the catalyst is used for preparing dihydric alcohol from olefin, linear alcohol can be obtained through a one-step method, and the content of by-products in a traditional series process is reduced. The method has the advantages of simple and convenient process, low cost and energy consumption, good production safety, high product quality and the like, and is particularly suitable for large-scale industrial production.
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Paragraph 0081; 0089-0090; 0099-0101
(2021/07/09)
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- Scope and limitations of biocatalytic carbonyl reduction with white-rot fungi
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The reductive activity of various basidiomycetous fungi towards carbonyl compounds was screened on an analytical level. Some strains displayed high reductive activities toward aromatic carbonyls and aliphatic ketones. Utilizing growing whole-cell cultures of Dichomitus albidofuscus, the reactions were up-scaled to a preparative level in an aqueous system. The reactions showed excellent selectivities and gave the respective alcohols in high yields. Carboxylic acids were also reduced to aldehydes and alcohols under the same conditions. In particular, benzoic, vanillic, ferulic, and p-coumaric acid were reduced to benzyl alcohol, vanillin, dihydroconiferyl alcohol and 1-hydroxy-3-(4-hydroxyphenyl)propan, respectively.
- Zhuk, Tatyana S.,Skorobohatko, Oleksandra S.,Albuquerque, Wendell,Zorn, Holger
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supporting information
(2021/02/02)
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- Iridium-Catalyzed Domino Hydroformylation/Hydrogenation of Olefins to Alcohols: Synergy of Two Ligands
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A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.
- Beller, Matthias,Huang, Weiheng,Jackstell, Ralf,Jiao, Haijun,Tian, Xinxin
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supporting information
(2022/01/13)
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- Silica-coated Fe3O4 magnetic nanoparticles-supported sulfonic acid as a highly active and reusable catalyst in chemoselective deprotection of tert-butyldimethylsilyl (TBDMS) ethers
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Anchored propyl sulfonic acid on the surface of silica-coated magnetic nanoparticles (Fe3O4@SiO2@PrSO3H) was successfully employed in the deprotection of TBDMS ethers. The prepared magnetically separable nanocatalyst exhibited efficient catalytic activity with high conversion and selectivity in cleavage of TBDMS ethers. TBDMS ethers are efficiently cleaved to the corresponding hydroxyl compounds in methanol solution containing 2 mol% magnetic nano-catalysts. Good to excellent yields of products, simple work-up and product separation, selective cleavage of TBDMS ethers in the presence of TBDPS ethers, easy recycling of the catalyst with external magnet with no loss in its activity (7 reaction cycles) are important features of this new protocol.
- Hossein Javadi, Sayed,Zareyee, Daryoush,Monfared, Azam,Didehban, Khadijeh,Mirshokraee, Sayed Ahmmad
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supporting information
p. 7 - 12
(2019/11/03)
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- Cobalt-catalysed selective synthesis of aldehydes and alcohols from esters
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Efficient and selective reduction of esters to aldehydes and alcohols is reported in which a simple cobalt pincer catalyst catalyses both transformations using diethylsilane as a reductant. Remarkably, the reaction selectivity is controlled by the stoichiometry of diethylsilane. This journal is
- Pattanaik, Sandip,Gunanathan, Chidambaram
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supporting information
p. 7345 - 7348
(2020/07/14)
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- Nickel-Catalyzed Formal Aminocarbonylation of Unactivated Alkyl Iodides with Isocyanides
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Herein, we disclose a Ni-catalyzed formal aminocarbonylation of primary and secondary unactivated aliphatic iodides with isocyanides to afford alkyl amide, which proceeds via the selective monomigratory insertion of isocyanides with alkyl iodides, subsequent β-hydride elimination, and hydrolysis process. The reaction features wide functional group tolerance under mild conditions. Additionally, the selective, one-pot hydrolysis of reaction mixture under acid conditions allows for expedient synthesis of the corresponding alkyl carboxylic acid.
- Chen, Yifeng,Huang, Wenyi,Qu, Jingping,Shrestha, Mohini,Wang, Yun,Weng, Yangyang
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supporting information
p. 3245 - 3250
(2020/04/21)
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- Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
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Aliphatic aldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphatic aldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon less homologous carbonyl compounds, the reduction of the same key intermediates followed by an oxidation produced one-carbon more homologous carbonyl compounds.
- Yoo, Jae Won,Seo, Youngran,Park, Jong Beom,Kim, Young Gyu
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- New strategy for production of primary alcohols from aliphatic olefins by tandem cross-metathesis/hydrogenation
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Primary alcohols are widely used in industry as solvents and precursors of detergents. The classic methods for hydration of terminal alkenes always produce the Markovnikov products. Herein, we reported a reliable approach to produce primary alcohols from terminal alkenes combining with biomass-derived allyl alcohol by tandem cross-metathesis/hydrogenation. A series of primary alcohol with different chain lengths was successfully produced in high yields (ca. 90percent). Computational studies revealed that self-metathesis and hydrogenation of substrates are accessible but much slower than cross-metathesis. This new methodology represents a unique alternative to primary alcohols from terminal alkenes.
- Jia, Ruilong,Zuo, Zhijun,Li, Xu,Liu, Lei,Dong, Jinxiang
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p. 1525 - 1529
(2019/11/11)
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- Metal complex catalysts and method for catalytically reducing carboxylic acids
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The invention relates to a metal complex catalyst, which contains at least one of metal complexes with a chemical formula comprising a structural unit represented by a formula I. According to the invention, the center metal of the metal complex catalyst is iridium, and the metal complex catalyst is composed of pentamethylcyclopentadienyl, a bitetrahydropyrimidine ligand and proper coordination anions; the metal complex catalyst has activity on a carboxylic acid reduction reaction, and a carboxylic acid compound is reduced into an alcohol compound in the presence of hydrogen; and the method ismild in reaction condition, can be carried out at room temperature, and is good in catalytic performance and high in reduction product yield.
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Paragraph 0085-0144; 0153; 0154; 0167-0168; 0178-0179
(2020/06/20)
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- In-Situ generation of surface-active HCo(CO)y like intermediate from gold supported on ion-promoted Co3O4 for induced hydroformylation-hydrogenation of alkenes to alcohols
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In this study, a greener and stable surface-active cobalt-carbonyl like specie [HCo(CO)y] was generated via H2 and CO spillover by gold on ion-promoted cobalt oxide. The supports and catalysts syntheses were based on inverse micelle and deposition-precipitation methods, respectively. The temperature-programmed reduction was used for optimization to obtain the best supports. The catalysts with activity (Co3O4 3O4 3O4 and Au loadings 10 percent 3O4 catalyst more active than the others and displayed excellent alcohol chemoselectivity with varying regioselectivity under milder reaction conditions. The reaction was assumed to take place via the formation of [HCo(CO)y] specie, as the active catalytic site of the catalyst. The enhanced catalytic performance was also ascribed to the low-temperature reducibility and surface basicity of the nanomaterials. The stability of the catalyst was evaluated by recycling, with its mesostructure retained after four cycles.
- Akinnawo, Christianah A.,Meijboom, Reinout,Mogudi, Batsile M.,Oseghale, Charles O.
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- Method for preparing alcoholic compound from aliphatic carboxylic acid without catalytic reaction
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The invention discloses a method for preparing an alcoholic compound from an aliphatic carboxylic acid without the catalytic reaction. In an inert gas atmosphere, 4,4,5,5-tetramethyl-1,3,2-dioxa-borolane and the carboxylic acid are evenly stirred and mixed in a dehydration and deoxidization reaction flask, and react for 8-10 hours to obtain a boric acid ester; and the carboxylic acid is acetic acid, caproic acid, valeric acid, heptylic acid, trimethylacetic acid, adipic acid and the like. The aliphatic carboxylic acid efficiently is used to react with borane to implement hydroboration withouta catalyst for the first time, and a novel scheme is provided for the preparation of the boric acid ester through hydroboration of a carbonyl compound and the borane and the further hydrolysis of theboric acid ester into an alcohol.
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- N-butyl lithium based fatty alcohol preparation method
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The invention relates to an n-butyl lithium based fatty alcohol preparation method. In an inert gas atmosphere, borane and aliphatic carboxylic acid are mixed, then n-butyl lithium taken as the catalyst is added to carry out hydroboration reactions; and after the hydroboration reactions, silica gel and methanol are added to carry out hydrolysis reactions to obtain the fatty alcohols. N-butyl lithium can efficiently catalyze the hydroboration reactions between carboxylic acids and borane at a room temperature, the used catalyst only accounts for 0.2 mol% of the carboxylic acids, compared with aconventional catalyst system, a commercial catalyst namely n-butyl lithium is adopted, the reaction conditions are mild, and the yield of fatty alcohols with different substitutes under restricted conditions is high.
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- Metal-Organic Architectures Assembled from Multifunctional Polycarboxylates: Hydrothermal Self-Assembly, Structures, and Catalytic Activity in Alkane Oxidation
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A three-component aqueous reaction system comprising copper(II) acetate (metal node), poly(carboxylic acid) with a phenylpyridine or biphenyl core (main building block), and 1,10-phenanthroline (crystallization mediator) was investigated under hydrothermal conditions. As a result, four new coordination compounds were self-assembled, namely, {[Cu(μ3-cpna)(phen)]·H2O}n (1), {[Cu(μ-Hbtc)(phen)]·H2O}n (2), {[Cu(μ3-Hcpic)(phen)]·2H2O}n (3), and [Cu6(μ-Hcptc)6(phen)6]·6H2O (4), where H2cpna = 5-(2′-carboxylphenyl)nicotinic acid, H3btc = biphenyl-2,4,4′-tricarboxylic acid, H3cpic = 4-(5-carboxypyridin-2-yl)isophthalic acid, H3cptc = 2-(4-carboxypyridin-3-yl)terephthalic acid, and phen = 1,10-phenanthroline. Crystal structures of compounds 1-3 reveal that they are 1D coordination polymers with a ladder, linear, or double-chain structure, while product 4 is a 0D hexanuclear complex. All of the structures are extended further [1D a?' 2D (1 and 2), 1D a?' 3D (3), and 0D a?' 3D (4)] into hydrogen-bonded networks. The type of a multicarboxylate building block has a considerable effect on the final structures of 1-4. The magnetic behavior and thermal stability of 1-4 were also investigated. Besides, these copper(II) derivatives efficiently catalyze the oxidation of cycloalkanes with hydrogen peroxide under mild conditions. The obtained products are the unique examples of copper derivatives that were assembled from H2cpna, H3btc, H3cpic, and H3cptc, thus opening up their use as multicarboxylate ligands toward the design of copper-organic architectures.
- Gu, Jinzhong,Wen, Min,Cai, Yan,Shi, Zifa,Arol, Aliaksandr S.,Kirillova, Marina V.,Kirillov, Alexander M.
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p. 2403 - 2412
(2019/02/28)
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- Silica-Supported MnII Sites as Efficient Catalysts for Carbonyl Hydroboration, Hydrosilylation, and Transesterification
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Manganese, the third most abundant transition-metal element after iron and titanium, has recently been demonstrated to be an effective homogeneous catalyst in numerous reactions. Herein, the preparation of silica-supported MnII sites is reported using Surface Organometallic Chemistry (SOMC), combined with tailored thermolytic molecular precursors approach based on Mn2[OSi(OtBu)3]4 and Mn{N(SiMe3)2}2?THF. These supported MnII sites, free of organic ligands, efficiently catalyze numerous reactions: hydroboration and hydrosilylation of ketones and aldehydes as well as the transesterification of industrially relevant substrates.
- Ghaffari, Behnaz,Mendes-Burak, Jorge,Chan, Ka Wing,Copéret, Christophe
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supporting information
p. 13869 - 13873
(2019/11/11)
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- Hierarchically constructed NiO with improved performance for catalytic transfer hydrogenation of biomass-derived aldehydes
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A 3D nano-/micrometer-scaled NiO material with urchin-like structure was prepared via a facile, green synthesis route, and served as a highly efficient and durable catalyst for catalytic transfer hydrogenation (CTH) of bio-based furfural (FF) to furfuryl alcohol (FAOL) using 2-propanol as H-donor and solvent. The as-prepared NiO possessed a good active-site accessibility owing to a high surface area and large amount of acid-base sites, resulting in high FF conversion of 97.3% with 94.2% FAOL yield at 120 °C and 3 h of reaction, which was a superior catalytic performance compared to commercial NiO nanoparticles. Besides, the excellent catalytic performance of the sea urchin-like NiO was validated for gram-scale FAOL synthesis, and recyclability test confirmed the catalyst to be reusable for multiple reaction runs without significant activity loss after intermediary calcination in air. Notably, the introduced catalytic system was also applicable to CTH of alternative bio-derived aldehydes.
- He, Jian,Nielsen, Monia Runge,Hansen, Thomas Willum,Yang, Song,Riisager, Anders
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p. 1289 - 1300
(2019/03/11)
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- Manganese(I)-Catalyzed Transfer Hydrogenation and Acceptorless Dehydrogenative Condensation: Promotional Influence of the Uncoordinated N-Heterocycle
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The four bidentate manganese(I) complexes [(C5H4N-C5H3N-OH)Mn(CO)3Br] (1), [(C9H6N-C5H3N-OH)Mn(CO)3Br] (2), [(C8H5N2-C5H3N-OH)Mn(CO)3Br] (3), and [(C8H5N2-C5H3N-OCH3)Mn(CO)3Br] (4) were synthesized. These complexes were tested as catalysts for the transfer hydrogenation of ketones, and 3 showed the highest activity. The reactions proceeded well with 0.5 mol % of catalyst loading and 20 mol % of t-BuOK at 85 °C for 24 h. Furthermore, 3 was also used as a catalyst for the synthesis of primary alcohols via transfer hydrogenation of aldehydes and the synthesis of 1,2-disubstituted benzimidazoles and quinolines via acceptorless dehydrogenative condensations.
- Zhang, Chong,Hu, Bowen,Chen, Dafa,Xia, Haiping
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p. 3218 - 3226
(2019/09/13)
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- Hydrosilylation of carbonyl and carboxyl groups catalysed by Mn(i) complexes bearing triazole ligands
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Manganese(i) complexes bearing triazole ligands are reported as catalysts for the hydrosilylation of carbonyl and carboxyl compounds. The desired reaction proceeds readily at 80 °C within 3 hours at catalyst loadings as low as 0.25 to 1 mol%. Hence, good to excellent yields of alcohols could be obtained for a wide range of substrates including ketones, esters, and carboxylic acids illustrating the versatility of the metal/ligand combination.
- Martínez-Ferraté, Oriol,Chatterjee, Basujit,Werlé, Christophe,Leitner, Walter
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p. 6370 - 6378
(2019/11/20)
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- DMSO-Triggered Complete Oxygen Transfer Leading to Accelerated Aqueous Hydrolysis of Organohalides under Mild Conditions
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Addition of DMSO is found to greatly accelerate the aqueous hydrolysis of organohalides to alcohols, providing a neutral, more efficient, milder and more economic process. Mechanistic studies using 18O-DMSO and 18O-H2O showed that, contrary to the opinion that DMSO works as a dipolar solvent to enhance water's nucleophilicity, the accelerating effect comes from a complete oxygen transfer from DMSO to organohalides through generation of ROS+Me2?X? salts through C?O bond formation, followed by O?S bond disassociative hydrolysis of ROS+Me2?X? with water. This method is applicable to a wide range of organohalides and thus may have potential for practical industrial application, owing to easy recovery of DMSO from the H2O/DMSO mixture by regular vacuum rectification.
- Liu, Haicheng,Liu, Jianping,Cheng, Xiaokai,Jia, Xiaojuan,Yu, Lei,Xu, Qing
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p. 2994 - 2998
(2019/01/04)
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- Modeling and optimization of lipase-catalyzed hydrolysis for production of (S)-2-phenylbutyric acid enhanced by hydroxyethyl-β-cyclodextrin
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An efficient reactive system was established to produce (S)-2-phenylbutyric acid (2-PBA) through the enzymatic enantioselective hydrolysis of 2-phenylbutyrate ester (2-PBAE) in aqueous medium. Lipase CALA from Canadian antarctica and hexyl 2-phenylbutyrate (2-PBAHE) were identified upon screening as the best enzyme and substrate, respectively. Adding hydroxyethyl-β-cyclodextrin (HE-β-CD) to improve the solubility of the substrate resulted in a 1.5 times increase in substrate conversion while retaining a high enantioselectivity compared with that when HE-β-CD was not added. The effects of lipase concentration, substrate concentration and HE-β-CD concentration, temperature, pH, and reaction time on enantiomeric excess and conversion rate were investigated, and the optimal conditions were identified using response surface methodology (RSM). Under the optimal conditions, namely 50 mg/mL lipase CALA, 30 mmol/L substrate, 60 mmol/L HE-β-CD, pH of 6.5, temperature of 83 °C and reaction time of 18 h, the enantiomeric excess and overall conversion rate were 96.05% and 27.28%, respectively. This work provides an efficient alternative method for improving the conversion of aromatic ester substrates by including β-cyclodextrin in an aqueous hydrolysis reaction system.
- Zhang, Panliang,Cheng, Qing,Xu, Weifeng,Tang, Kewen
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- Synthesis and characterization of water-soluble arene-ruthenium complexes and their application in biphasic olefin oxidation
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New water-soluble complexes [(η6-C6H6)RuCl(C5H4N-2-CH = N-R)]Cl (1) (with R = 4-hydroxymethylphenyl (a), 2,4-dichlorophenyl (b), 2-fluorophenyl (c), 3-carboxyphenyl (d)) have been synthesized by reacting [(η6-C6H6)Ru(μ-Cl)Cl]2 with the N,N′-bidentate ligands in a 1:2 ratio. Full characterization of all complexes was accomplished using 1H and 13C NMR, elemental analyses, UV-Vis spectroscopy, IR spectroscopy and single crystal X-ray crystallography for determination of the structure of 1d, as 1d·4H2O. The single crystal structure confirmed coordination of the ligand to the ruthenium(II) center leading to a structure commonly described as a pseudo-octahedral, three-legged piano stool. The geometry around the Ru(II) center is such that the arene ring occupies the apex of the stool while the N,N′-bidentate ligand and a chloride occupy the base of the stool. The synthesized Ru(II) complexes were tested as catalysts for oxidation of styrene using NaIO4 as a co-oxidant in a biphasic system. All complexes were active, giving good yields of benzaldehyde. Catalyst 1c was later investigated for olefin oxidation and gave high yields of the corresponding aldehydes as the major products in all cases.
- Gichumbi, Joel M.,Friedrich, Holger B.,Omondi, Bernard
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p. 135 - 147
(2019/01/04)
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- Ruthenium-Catalyzed Deoxygenative Hydroboration of Carboxylic Acids
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An efficient deoxygenative hydroboration of carboxylic acids to alkyl boronate esters under mild reaction condition is reported. Both aromatic and aliphatic carboxylic acids exhibited excellent reactivities with minimal catalyst load of 0.1 mol% and reactions occurred under neat conditions. This catalytic transformation selectively provides alkyl boronate esters, which can be conveniently hydrolyzed to obtain the corresponding alcohols. Remarkably, this reduction reaction proceeds with the liberation of molecular hydrogen.
- Kisan, Sesha,Krishnakumar, Varadhan,Gunanathan, Chidambaram
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p. 4772 - 4776
(2018/06/08)
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- New oxidovanadium(iv) complex with a BIAN ligand: synthesis, structure, redox properties and catalytic activity
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Reaction of VCl3 with bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) in air afforded [VOCl2(dpp-bian)] (1). The complex was characterized by IR and UV-vis spectroscopies and elemental analysis. The crystal structure of 1 was determined by X-ray diffraction (XRD) analysis. The vanadium atom is in a square-pyramidal OCl2N4 coordination environment. The cyclic voltammogram (CV) in dichloromethane reveals an irreversible oxidation process at +1.40 V (vs. Ag/AgCl) assigned to the V(iv)/V(v) couple, and two consecutive quasi-reversible one-electron reduction processes at ?0.32 V and ?1.05 V (vs. Ag/AgCl), respectively, assigned to the bian/bian?/ and bian?//bian2? couples, followed by irreversible reduction at ?1.6 V (vs. Ag/AgCl). The EPR spectrum of 1 in toluene shows a single 8-line signal typical for oxidovanadium(iv) complexes with d1 configuration. The magnetic behavior of 1 confirms the presence of one unpaired electron (μeff (330 K) = 1.67 μB), and the isolation of the paramagnetic centers. Application of 1 to oxidation of alkanes documented high catalytic activity under mild conditions. The kinetics and selectivity of alkane oxygenation by the 1/H2O2 and 1/PCA/H2O2 systems (PCA is pyrazine-2-carboxylic acid) were studied. The reaction is more efficient in the presence of PCA.
- Fomenko, Iakov S.,Gushchin, Artem L.,Shul'pina, Lidia S.,Ikonnikov, Nikolay S.,Abramov, Pavel A.,Romashev, Nikolay F.,Poryvaev, Artem S.,Sheveleva, Alena M.,Bogomyakov, Artem S.,Shmelev, Nikita Y.,Fedin, Matvey V.,Shul'pin, Georgiy B.,Sokolov, Maxim N.
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supporting information
p. 16200 - 16210
(2018/10/04)
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- Ambient-Pressure and Base-Free Aldehyde Hydrogenation Catalyst Supported by a Bifunctional Abnormal NHC Ligand
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Catalytic aldehyde hydrogenation is an essential and routinely used chemical synthesis process in both academia and industry. However, there is a serious scarcity of efficient homogeneous catalysts for this process to work under highly demanding atmospheric-pressure, base-free, and aqueous conditions. Addressing this problem, herein, we report an iridium-based catalyst for facile atmospheric-pressure and base-free hydrogenation of various aromatic, heteroaromatic, and aliphatic aldehydes. The catalyst also displays excellent chemoselectivity toward aldehyde over other carbonyl functionalities and unsaturated motifs. Moreover, the catalyst is found to work in H2O (and in H2O-ethanol) medium at ambient temperature. All of the above attributes have been possible to incorporate into this unique catalyst via employing a hybrid bifunctional ligand, which plays a crucial role in facilitating the cleavage of H2 as well as effectively delivering hydride to the substrate without any help of base or pressure.
- Garhwal, Subhash,Maji, Babulal,Semwal, Shrivats,Choudhury, Joyanta
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supporting information
p. 4720 - 4725
(2018/12/14)
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- Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions
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We recently reported a novel hybrid batch-flow synthesis of the antipsychotic drug clozapine in which the reduction of a nitroaryl group is described under flow conditions using sodium dithionite. We now report the expansion of this method to include the reduction of aldehydes. The method developed affords yields which are comparable to those under batch conditions, has a reduced reaction time and improved space-time productivity. Furthermore, the approach allows the selective reduction of aldehydes in the presence of ketones and has been demonstrated as a continuous process.
- Neyt, Nicole C.,Riley, Darren L.
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supporting information
p. 1529 - 1536
(2018/07/05)
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- Visible light-driven selective hydrogenation of unsaturated aromatics in an aqueous solution by direct photocatalysis of Au nanoparticles
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Selective hydrogenation of various chemical bonds, such as CC, CC, CO, NO, and CN, is efficiently driven by visible light over a supported gold nanoparticle (AuNP) photocatalyst under mild reaction conditions. The reaction system exhibits high substituent tolerance and tunable selectivity by light wavelength. Density functional theory (DFT) calculations demonstrated a strong chemisorption between the reactant molecule and metal resulting in hybridized orbitals. It is proposed that direct photoexcitation between hybridized orbitals is the main driving force of the hydrogenation reaction. The hydrogenation pathway is investigated by the isotope tracking technique. We revealed the cooperation of water and formic acid (FA) as a hydrogen source and the hydrogenation route through Au-H species on the AuNP surface.
- Huang, Yiming,Liu, Zhe,Gao, Guoping,Xiao, Qi,Martens, Wayde,Du, Aijun,Sarina, Sarina,Guo, Cheng,Zhu, Huaiyong
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p. 726 - 734
(2018/02/14)
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- Magnetic nickel ferrite nanoparticles as highly durable catalysts for catalytic transfer hydrogenation of bio-based aldehydes
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Magnetic nickel ferrite (NiFe2O4) nanoparticles were exploited as stable and easily separable heterogeneous catalysts for catalytic transfer hydrogenation (CTH) of furfural to furfuryl alcohol with 2-propanol as both the hydrogen source and the solvent providing 94% product yield at 180 °C after 6 h of reaction. The magnetic properties of the catalysts provided facile recovery using an external magnet after reaction allowing it to be reused in five reaction cycles without loss of catalytic performance. Importantly, the NiFe2O4 nanoparticles were also applicable to CTH of other alkenyl/allyl/aromatic aldehydes affording over 94% selectivity towards the targeted alcohol products, thus being attractive as highly universal catalysts for CTH of aldehydes.
- He, Jian,Yang, Song,Riisager, Anders
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p. 790 - 797
(2018/02/14)
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- Lanthanide aryloxides catalyzed hydroboration of aldehydes and ketones
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The lanthanide aryloxides Ln(OAr)3(THF)2 (Ar = Ar1 = 2,6-tBu2-4-MeC6H2, Ln = Yb (1), Y (2); Ar = Ar2 = 2,6-iPr2C6H3, Ln = Y (3); Ar = Ar3 = 2,6-Me2C6H3, Ln = Y (4); Ar = Ar1, Ln = Sm (5), Nd (6)) could be served as highly efficient catalysts for the hydroboration of aldehydes and ketones with good functional group tolerance and excellent chemoselectivity. Computational studies were carried out to probe a feasible mechanism of the Ln-aryloxides catalyzed hydroboration of aldehydes/ketones.
- Zhu, Zhangye,Dai, Ping,Wu, Zhenjie,Xue, Mingqiang,Yao, Yingming,Shen, Qi,Bao, Xiaoguang
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- An efficient and sustainable catalytic reduction of carbon-carbon multiple bonds, aldehydes, and ketones using a Cu nanoparticle decorated metal organic framework
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Transition metal (Cu, Mn, Ni, Zr) substituted metal organic frameworks (MOFs) are prepared for the reduction of carbon-carbon multiple bonds with hydrazine hydrate in ethanol under mild reaction conditions. Among the MOFs investigated in this study, the Cu framework substituted MOF exhibited the best activity in this study. Further, Cu nanoparticles (CuNPs) are supported on the surface of a Cu framework substituted MOF to achieve excellent reduction activity. The catalyst exhibits efficient recyclability with no appreciable loss in the catalytic activity even after five recycles. In order to establish the reaction mechanism, reactions are performed under N2 and Ar atmospheres. A reaction is also performed under an Ar atmosphere but in the presence of H2O2 to elucidate the mechanism. The catalyst exhibits excellent activity in the reduction of alkynes. Under the optimum reaction conditions, the catalyst is also successful in reducing a wide range of aldehydes and ketones. The present catalytic process demonstrates several key advantages such as mild and convenient reaction conditions, a low substrate to hydrazine ratio, reusability, and cost-effectiveness of the catalyst (Pt or Pd free catalyst).
- Kar, Ashish Kumar,Srivastava, Rajendra
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p. 9557 - 9567
(2018/06/18)
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- Iron(II)-Catalyzed Site-Selective Functionalization of Unactivated C(sp3)?H Bonds Guided by Alkoxyl Radicals
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An alkoxyl radical guided strategy for site-selective functionalization of unactivated methylene and methine C?H bonds enabled by an FeII-catalyzed redox process is described. The mild, expeditious, and modular protocol allows efficient remote aliphatic fluorination, chlorination, amination, and alkynylation of structurally and electronically varied primary, secondary, and tertiary hydroperoxides with excellent functional-group tolerance. The application for one-pot 1,4-hydroxyl functionalization of non-oxygenated alkane substrates initiated by aerobic C?H oxygenation is also demonstrated.
- Guan, Honghao,Sun, Shutao,Mao, Ying,Chen, Lei,Lu, Ran,Huang, Jiancheng,Liu, Lei
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supporting information
p. 11413 - 11417
(2018/08/28)
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- Reliably Regioselective Dialkyl Ether Cleavage with Mixed Boron Trihalides
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A protocol for the regioselective cleavage of unsymmetrical alkyl ethers to generate alkyl alcohol and alkyl bromide products is described. A mixture of trihaloboranes triggers this conversion and exhibits improved reactivity profiles (regioselectivity and yield) compared with BBr3 alone. Additionally, this procedure allows the efficient synthesis of (B-Cl) dialkyl boronate esters. There are limited methods to generate acyclic dialkoxyboryl chlorides, and these intermediates constitute important synthons in main-group chemistry.
- Atienza, Bren Jordan P.,Truong, Nam,Williams, Florence J.
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supporting information
p. 6332 - 6335
(2018/10/09)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Solvent- and base-free synthesis of wax esters from fatty acid methyl esters by consecutive one-pot, two-step catalysis
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The one-pot, two-step synthesis of wax esters was successfully conducted by consecutive homogeneous ruthenium-catalysed hydrogenation-dehydrogenation reactions of fatty acid methyl esters, in the absence of solvent and of base additive. Under optimized conditions, excellent conversion and selectivity were reached. Furthermore, physicochemical investigations revealed that the resulting compounds display properties similar to benchmark commercial products extracted from natural sources of lesser availability compared to the herein considered bioresources, making this chemical route very promising regarding further potential industrial implementation.
- Nguyen,Raffa,Morin,Desset,Capet,Nardello-Rataj,Dumeignil,Gauvin
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supporting information
p. 5665 - 5673
(2017/12/06)
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- A Manganese Pre-Catalyst: Mild Reduction of Amides, Ketones, Aldehydes, and Esters
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A new (N-phosphinoamidinate)manganese complex is shown to be a useful pre-catalyst for the hydrosilative reduction of carbonyl compounds, and in most cases at room temperature. The Mn-catalyzed reduction of tertiary amides to tertiary amines, with a useful scope, is demonstrated for the first time by use of this catalyst, and is competitive with the most effective transition-metal catalysts known for such transformations. Ketones, aldehydes, and esters were also successfully reduced under mild conditions by using this new Mn catalyst.
- Kelly, Colin M.,McDonald, Robert,Sydora, Orson L.,Stradiotto, Mark,Turculet, Laura
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supporting information
p. 15901 - 15904
(2017/12/13)
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- Facile and effective approach for oxidation of boronic acids
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This present work illustrates facile and effective approach for oxidation of boronic acids using environmentally benign dimethyl carbonate (DMC) as a solvent with H2O2 as an oxidant at room temperature. In contrast to previous reaction reports, which make use of metal catalyst, hazardous reagent and oxidants that creates environmental concern. This method provides good to excellent yield of products and showed better tolerance towards various functional groups present on boronic acids. Moreover, this developed process is an alternative in terms of inexpensive, non toxic and easy reaction conditions.
- Wagh, Ravindra B.,Nagarkar, Jayashree M.
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supporting information
p. 4572 - 4575
(2017/11/03)
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- Method for preparing alcohol by hydrolyzing halogenated hydrocarbon
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The invention provides a method for preparing alcohol by hydrolyzing halogenated hydrocarbon. According to the invention, the relatively low-cost halogenated hydrocarbon is used as a raw material, a low-toxic stable mixture of DMSO and water is used as a solvent, no additional catalyst is required, and the halogenated hydrocarbon can be directly hydrolyzed into corresponding alcohol by only adding little alkali or additive into low-activity halogenated hydrocarbon. According to method, the inert gas shielding is not required, the operation is simple and feasible, the requirement for the experimental equipment is low, the product yield is high, and the method is suitable for preparing different types of alcohol by hydrolyzing different types of halogenated hydrocarbon. Thus, the method has certain theoretical research values and potential application prospects.
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Paragraph 0070; 0071; 0072; 0073
(2017/10/22)
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- Atmospheric Hydrogenation of Esters Catalyzed by PNP-Ruthenium Complexes with an N-Heterocyclic Carbene Ligand
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New pincer ruthenium complexes bearing a monodentate N-heterocyclic carbene ligand were synthesized and demonstrated as powerful hydrogenation catalysts. With an atmospheric pressure of hydrogen gas, aromatic, heteroaromatic, and aliphatic esters as well as lactones were converted into the corresponding alcohols at 50 °C. This reaction protocol offers reliable access to alcohols using an easy operational setup.
- Ogata, Osamu,Nakayama, Yuji,Nara, Hideki,Fujiwhara, Mitsuhiko,Kayaki, Yoshihito
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supporting information
p. 3894 - 3897
(2016/08/16)
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- ALKANE OXIDATION BY MODIFIED HYDROXYLASES
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This invention relates to modified hydroxylases. The invention further relates to cells expressing such modified hydroxylases and methods of producing hydroxylated alkanes by contacting a suitable substrate with such cells.
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Paragraph 0339
(2016/02/16)
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- High Catalytic Efficiency Combined with High Selectivity for the Aldehyde-Water Shift Reaction using (para-cymene)Ruthenium Precatalysts
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A family of (para-cymene)RuII complexes are shown to be competent precatalysts for the oxidation of aldehydes to carboxylic acids using water as the oxidant. This reaction, known as the "aldehyde-water shift" (AWS), has been previously demonstrated to be in competition with aldehyde disproportionation. For the few reported mononuclear catalysts for this reaction, either high selectivity for AWS and low conversion or low AWS selectivity and high conversion is observed. A homogeneous precatalyst which is both highly selective for the desired AWS and is highly efficient for conversion of the aldehyde to products is reported herein. In addition, catalyst activity is found to be general to a variety of sterically unencumbered aliphatic aldehydes producing the corresponding carboxylic acid and hydrogen gas.
- Brewster, Timothy P.,Goldberg, Jonathan M.,Tran, Jeremy C.,Heinekey, D. Michael,Goldberg, Karen I.
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p. 6302 - 6305
(2016/09/09)
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- A furan or tetrahydrofuran by the green primary alcohol derivatives for the preparation of the new method
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The invention provides a novel method for preparing middle/long-chain primary alcohol from furan or tetrahydrofuran derivatives. Specifically, a double-function catalyst is adopted, and such catalyst comprises two activity centers, namely, a hydrogenation activity center and an acid center; water is taken as a solvent in the reaction, the reaction is carried out in a batch reactor, and by utilizing the characteristic that the middle/long-chain primary alcohol is not dissolved in water, the generated primary alcohol is naturally separated from water and the catalyst, and alkane is prevented from being generated because of hydrogen over-addition or hydrogenolysis. Due to the characteristic that the primary alcohol and the water are not dissolved with each other, the primary alcohol can be conveniently separated, the separation cost is greatly lowered, and good industrial prospect is achieved.
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Paragraph 0012; 0013; 0015; 0018
(2017/02/17)
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