- Process Development for the Rhodium-Catalyzed Reductive Amination in a Thermomorphic Multiphase System
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For the first time, the successful application of the homogeneously catalyzed reductive amination in a thermomorphic multiphase system (TMS) and the first reported scale-up of this reaction into a continuous process, which recovers and recycles the homogeneous catalyst in flow, is presented. Herein, the model substrate 1-decanal reacts with the secondary amine diethylamine to form the corresponding product N,N-diethyldecylamine. A thermomorphic multiphase system (TMS) is established as a recycling strategy to recover and reuse the catalyst for the continuous process. After screening different solvents for the TMS and optimizing the reaction conditions in batch mode, the recycling of the rhodium catalyst was realized in a fully automated miniplant. Parameters influencing the stability of the process were identified and optimized to develop the continuous process. The process was operated in a steady state over 90 h with yields >90% of the desired product and low catalyst leaching 1%/h.
- Künnemann, Kai U.,Bianga, Jonas,Scheel, Ricarda,Seidensticker, Thomas,Dreimann, Jens M.,Vogt, Dieter
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- Reduction of Carboxylic Acid with 2-Propanol over Zirconia-Titania
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The reduction of long carbon chain carboxylic acids or the esters with 2-propanol proceeded efficiently over zirconia-titania at atmospheric pressure, and the corresponding alcohols were obtained.Methyl 9-octadecenoate was reduced to give 9-octadecen-1-ol in a 58percent yield.
- Takahashi, Kyoko,Shibagaki, Makoto,Kuno, Hideyuki,Matsushita, Hajime
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- Reduction of aldehydes using trialkylboranes in ionic liquids
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Non-aqueous ionic liquids, molten salts, have been found to enhance organoboron mediated reductions of aldehydes.
- Kabalka,Malladi
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- Deprotection of mono and dimethoxy phenyl methyl ethers using catalytic amounts of DDQ
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4-Methoxy and 3,4 dimethoxy benzyl ethers have been deprotected with catalytic amounts of DDQ by oxidative recycling of the byproduct DDHQ with FeCl3 for the first time.
- Chandrasekhar,Sumithra,Yadav
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- Selective Removal of the Methyldiphenylsilyl Protecting Group Using Azide Ion
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Sodium azide in dimethylformamide effects the cleavage of the methyldiphenylsilyl ether bond under conditions whereby t-butyldimethylsilyl ethers and t-butyldiphenylsilyl ethers are stable.
- Monger, Steven J.,Parry, David M.,Roberts, Stanley M.
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- Hydrogen transfer hydrozirconation of alkenes with iBuZrCp2Cl catalyzed by Lewis-acidic metal compounds containing Al, Zn, Si, Ag, and Pd
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The hydrozirconation reaction of monosubstituted alkenes with iBuZrCp2Cl can be significantly accelerated by catalytic amounts of various Lewis acidic metal compounds, most notably AlCl3, Me3SiI, and Pd complexes, such as Li2PdCl4 and Cl2Pd(PPh3)2.
- Makabe, Hidefumi,Negishi, Ei-Ichi
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- Structure sensitivity in the ruthenium nanoparticle catalyzed aqueous-phase Fischer-Tropsch reaction
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Low-temperature Fischer-Tropsch reaction data are reported for Ru nanoparticles suspended in the water phase. Their activity and selectivity strongly depends on particle size, when varied between 1 to 5 nm. Small particles display high oxygenates selectivity. The Anderson-Schulz-Flory (ASF) chain-growth probability for oxygenates is significantly lower than that observed for hydrocarbons. The chain growth parameter for hydrocarbon formation is independent of particle size. For oxygenates it is constant only for particles larger than 3 nm. Oxygenate and hydrocarbon formation occur on different sites. The ASF chain-growth probability for oxygenate formation increases with temperature. For very small 1.2 nm particles it shows a maximum as a function of temperature. This unusual temperature dependence is due to relatively slow CO dissociation compared to the rate of C-C bond formation. This journal is
- Quek, Xian-Yang,Pestman, Robert,Van Santen, Rutger A.,Hensen, Emiel J. M.
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- Convenient method for the preparation of catecholborane and promotion of the formation of alkenyl catecholborane using BH3 complexes
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Catecholborane is prepared in benzene by passing B2H6, generated from I2/NaBH4, through a suspension of catechol at 25 deg C.The reagent prepared in this way is used for hydroboration-oxidation of representative alkenes and alkynes at 80 deg C.Hydroboration of 1-alkynes followed by iodination with I2/NaOH gives the corresponding trans-1-alkenyl iodides in 70-72percent yield.The alkenyl catecholboranes can be prepared at 25 deg C by performing the reaction in the presence of 10 molepercent of H3B:N(C2H5)2Ph or H3B:THF.The reaction is believed to go through hydroboration of thealkynes by borane followed by exchange with catecholborane.Studies of the preparation of dialkylphenoxyboranes and alkenyldiphenoxyboranes through hydroboration of 1-decene and 1-decyne by use of H3B:N(C2H5)2Ph and phenol are also reported.
- Suseela, Y.,Periasamy, M.
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- Deprotection of benzyl ethers using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) under photoirradiation
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The deprotection of benzyl ethers was effectively realized in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in MeCN under photoirradiation using a long wavelength UV light.
- Rahim, Mohammad Abdur,Matsumura, Shuichi,Toshima, Kazunobu
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- Reactions of Amino Acid Decyl Esters with Nucleophiles Catalyzed by Polymer-Supported Amine-Metal Complexes
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The reactions of alanine decyl ester (AlaODc) with nucleophiles were catalyzed by a crosslinked polystyrene-supported ethylenediamine-copper(II) ion complex (Cu en-PS) under toluene/resin two-phase conditions or toluene/ aqueous buffer/resin three-phase conditions.In the two-phase reactions with octylamine, the rate was increased with a decreasing metal content of the resin.The catalytic efficiency was also dependent on other factors, that is, metal ion, ligand structure, and substrate structure.In the three-phase reactions with water, the hydrolysis was very fast when acetate ions were present in the aqueous phase.It has been suggested that the reactions proceed via a substrate-coordinated intermediate complex under both conditions.
- Ohtani, Noritaka,Inoue, Yukihiko,Inagaki, Yuichi,Fukuda, Kenji,Nishiyama, Taisuke
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- Unexpected deprotection of silyl and THP ethers induced by serious disparity in the quality of Pd/C catalysts and elucidation of the mechanism
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Commercial Pd/C catalysts show different catalytic activity toward the deprotection of silyl and THP ethers. The Pd/C purchased from Merck and ACROS exhibits marked tendency to cleave these protective groups unexpectedly without hydrogen conditions although Aldrich's Pd/C (20,569-9) is inactive in the absence of hydrogen. It was proved that the Pd/C disparity toward the deprotection of TES and THP ethers results from residual acids and/or palladium chloride in the production process of Pd/Cs. Although a TES ether cleavage reaction in the absence of hydrogen and a THP ether cleavage reaction in the presence of hydrogen using 10% Pd/C were recently published, we could conclude they were only an acid-catalyzed solvolysis, the acid being released from the catalyst. Hydrogen is essential for the actual 10% Pd/C-catalyzed cleavage of TES ethers and THP ethers which must be stable under the true Pd/C-catalyzed hydrogenation conditions.
- Ikawa, Takashi,Sajiki, Hironao,Hirota, Kosaku
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- THERMAL STABILITY IN RELATION TO HYDROLYSIS OF SODIUM DECYLSULPHATE IN A SOLUTION WITH NEMATIC LYOTROPIC PROPERTIES.
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Studied the effect of temperature as a function of time on sodium decylsulphate in the ternary nematic solution first proposed by Radley and Reeves. The hydrolysis of the ester was followed by recording the pH-profile and by determining the liberated decanol. It was found that the ester was subject to slow uncatalyzed hydrolysis in the beginning and to much faster acid catalyzed hydrolysis later on. The decylsulphate underwent insignificant cleavage over 48 hours up to at least 70 degree C with perfect retention of the nematic phase. The results showed that the chemical stability was as good as that of many thermotropic compounds.
- Hochapfel,Boidart,Laurent
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- Transfer hydrogenation of aromatic and linear aldehydes catalyzed using Cp*Ir(pyridinesulfonamide)Cl complexes under base-free conditions
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Cp*Ir(pyridinesulfonamide)Cl (Cp*?=?pentamethylcyclopentadienyl) precatalysts 1–7 are active for the transfer hydrogenation of aryl, alkyl, and heterocyclic aldehydes. Catalysis is conducted under base-free conditions in air without dried or degassed substrates and solvents. These reductions occur rapidly in moderate to high conversion (39–100%). Benzaldehyde derivatives are reduced to alcohols within 30?min?at 85?°C using 1?mol% iridium precatalyst; reduction also occurs at lower temperatures and loadings (60?°C, 0.50?mol% precatalyst). Benzaldehyde derivatives that possess electron-rich and electron-poor substituents in the para position, including base-sensitive 4-hydroxybenzaldehyde, are readily reduced. Aryl aldehydes containing electron-poor groups are reduced faster than substrates possessing electron-rich moieties. Reduction of the positional isomers of methoxybenzaldehyde and isopropylbenzaldehyde shows highest reduction for the ortho isomer, followed by the meta isomer. Heterocyclic substrates, including biomass derived 5-hydroxymethylfurfural and 2-furfural, were reduced selectively to the alcohol. Decyl aldehyde was reduced to the linear alcohol; importantly self-condensation was not observed. Competition studies demonstrated selective reduction of aldehydes over ketones and a mercury poisoning experiment supports a homogeneous catalyzed pathway.
- Townsend, Tanya M.,Kirby, Christopher,Ruff, Andrew,O'Connor, Abby R.
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- Novel deprotection of SEM ethers: A very mild and selective method using magnesium bromide
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(Matrix presented) New lability and stability sequences have been established for multifunctional substrates containing SEM ether group(s) by a MgBr2/Et2O/ MeNO2 deprotection protocol.
- Vakalopoulos, Alexandros,Hoffmann
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- A mild, efficient, and selective method for the desilylation of more common trialkylsilyl ethers by cerium(III) chloride heptahydrate and sodium iodide in acetonitrile
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Treatment of trialkylsilyl ethers with cerium(III) chloride heptahydrate and sodium iodide in acetonitrile provides a simple, convenient, and chemoselective process for desilylation, and the parent alcohol was obtained in high yield. The trialkylsilyl ethers have been cleaved selectively in the presence of acetate, benzyl and tetrahydropyranyl ethers.
- Bartoli, Giuseppe,Bosco, Marcella,Marcantoni, Enrico,Sambri, Letizia,Torregiani, Elisabetta
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- Hydrogenation versus hydrogenolysis with a safe, selective and reusable catalyst: Palladium black on Teflon
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Palladium black deposit is obtained by reduction and metallization of the Teflon polymer surface of magnetic stirring bars. These stirring bars can be used to perform selective hydrogenation of olefins and acetylenic compounds whilst hydrogenolysis is not observed. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Belotti, Damien,Cantagrel, Guillaume,Combellas, Catherine,Cossy, Janine,Kanoufi, Frederic,Nunige, Sandra
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- Cleavage of the THP protecting group under Pd/C-catalyzed hydrogenation conditions
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Alcohol and phenol THP or ethoxyethyl ether protecting groups may be cleaved in high yield under Pd/C-catalyzed hydrogenation conditions in EtOH, owing to the inadvertent presence of small quantities of HCl in the reaction mixture. MOM ethers are not cleaved under these conditions.
- Kaisalo, Leena,Hase, Tapio
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- Significant supplier-dependent disparity in catalyst activity of commercial Pd/C toward the cleavage of triethylsilyl ether
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Pd/C catalysts exhibit remarkable supplier-dependent difference in catalyst activity and property. Some commercial Pd/C catalysts are quite acidic. Although a TES ether cleavage reaction using 10% Pd/C in the absence of hydrogen was quite recently published, we could conclude it was only an acid, released from the catalyst, catalyzed solvolysis, and hydrogen is essential for the actual 10% Pd/C-catalyzed cleavage of a TES ether.
- Sajiki, Hironao,Ikawa, Takashi,Hirota, Kosaku
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- Transition metal catalysis in fluorous media: Practical application of a new immobilization principle to rhodium-catalyzed hydroborations of alkenes and alkynes
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Addition of a yellow-orange toluene solution of [Rh(C1)(COD)]2 to a colorless CF3C6F11 solution of P(CH2CH2R(f6))3 (R(f6) = (CF2)5CF3)3) gives a colorless toluene solution of COD and an orange CF3C6F11 solution of ClRh[P(CH2CH2R(f6))3]3 (1). Evaporation of CF3C6F11 gives analytically pure 1 (94%), which is insoluble in most organic solvents and stable to 300 °C. Alkenes, catecholborane, and CF3C6F11 solutions of 1 (950:950:1 mol ratio for norbomene) are stirred for 1-24 h at 40 °C (heterogeneous conditions). The resulting alkylboranes are extracted with benzene (2x; turnover number (TON) 854 (90%) for norbornene), toluene, or THF, and the catalyst solution is reused (TON 2409 for three cycles). Subsequent reactions with H202/NaOH give alcohols, which are isolated in 92-77% yields (11 examples). Longer reaction times afford TON values higher than 10000 (2CH2R(f8))3]3 (2), and the nonfluorinated analogue ClRh[P((CH2)7CH3)3]3 are similarly prepared. Solubilities and reactivities are compared. Atomic absorption analyses shows rhodium losses of 0.4% (1) and 0.2% (2) per cycle, corresponding to 4.52.2 ppm rhodium/mol of addition product. These data demonstrate the viability and practicality of an exciting new approach to catalyst immobilization. Addition of a yellow-orange toluene solution of [Rh(Cl)(COD)]2 to a colorless CF3C6F11 solution of P(CH2CH2Rf6)3 (Rf6 = (CF2)5CF3)3) gives a colorless toluene solution of COD and an orange CF3C6F11 solution of ClRh[P(CH2CH2Rf6)3]3 (1). Evaporation of CF3C6F11 gives analytically pure 1 (94%), which is insoluble in most organic solvents and stable to 300 °C. Alkenes, catecholborane, and CF3C6F11 solutions of 1 (950:950:1 mol ratio for norbornene) are stirred for 1-24 h at 40 °C (heterogeneous conditions). The resulting alkylboranes are extracted with benzene (2×; turnover number (TON) 854 (90%) for norbornene), toluene, or THF, and the catalyst solution is reused (TON 2409 for three cycles). Subsequent reactions with H2O2/NaOH give alcohols, which are isolated in 92-77% yields (11 examples). Longer reaction times afford TON values higher than 10000 (2CH2Rf8)3]3 (2), and the nonfluorinated analogue ClRh[P((CH2)7CH3)3]3 are similarly prepared. Solubilities and reactivities are compared. Atomic absorption analyses shows rhodium losses of 0.4% (1) and 0.2% (2) per cycle, corresponding to 4.5-2.2 ppm rhodium/mol of addition product. These data demonstrate the viability and practicality of an exciting new approach to catalyst immobilization.
- Juliette, Jerrick J. J.,Rutherford, Drew,Horváth, István T.,Gladysz
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- Copper(II) chloride dihydrate: A catalytic agent for the deprotection of tetrahydropyranyl ethers (THP ethers) and 1-ethoxyethyl ethers (EE ethers)
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Tetrahydropyranyl ethers (THP groups) and 1-ethoxyethyl ethers (EE groups) are removed upon refluxing in 95% EtOH or Me2CO-H2O (95:5) in the presence of a catalytic amount of copper(II) chloride dihydrate (2-5 mol%).
- Wang, Jianbo,Zhang, Chao,Qu, Zhaohui,Hou, Yihua,Chen, Bei,Wu, Peng
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- An Immobilized Organotin Catalyst for Reduction of Ketones and Aldehydes
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A dialkyltin dimethoxide linked to the surface of silica functions as an efficient and readily recovered and recycled hydride transfer catalyst for the reduction of ketones and aldehydes using polymethylhydrosiloxane as the hydrogen source.
- Matlin, Stephen A.,Gandham, Permjit S.
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- Preparation of samarium(II) iodide: Quantitative evaluation of the effect of water, oxygen, and peroxide content, preparative methods, and the activation of samarium metal
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Samarium(II) iodide (SmI2) is one of the most important reducing agents in organic synthesis. Synthetic chemistry promoted by SmI2 depends on the efficient and reliable preparation of the reagent. Unfortunately, users can experience difficulties preparing the reagent, and this has prevented realization of the full synthetic potential of SmI2. To provide synthetic chemists with general and reliable methods for the preparation of SmI2, a systematic evaluation of the factors involved in its synthesis has been carried out. Our studies confirm that SmI2 is a user-friendly reagent. Factors such as water, oxygen, and peroxide content in THF have little influence on the synthesis of SmI2. In addition, the use of specialized glovebox equipment or Schlenk techniques is not required for the preparation of SmI2. However, our studies suggest that the quality of samarium metal is an important factor and that the use of low quality metal is the main cause of failed preparations of the reagent. Accordingly, we report a straightforward method for activation of "inactive" samarium metal and demonstrate the broad utility of this protocol through the electron transfer reductions of a range of substrates using SmI2 prepared from otherwise "inactive" metal. An investigation into the stability of SmI2 solutions and an evaluation of commercially available solutions of the reagent is also reported.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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- REACTIONS OF ALLYLIC CARBONATES CATALYZED BY PALLADIUM, RHODIUM, RUTHENIUM, MOLYBDENUM, AND NICKEL COMPLEXES; ALLYLATION OF CARBONUCLEOPHILES AND DECARBOXYLATION-DEHYRDOGENATION
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Allylation of carbonucleophiles with allylic carbonates catalyzed by various transition metal complexes has been studied.Palladium, rhodium, ruthenium, nickel, and molybdenum complexes were found to be active catalysts.The rhodium catalyst showed a different regioselectivity from the other catalysts, the reaction can proceed without allylic rearrangement.In the absence of nucleophiles, allyl alkyl carbonates were converted into ketones by decarboxylation-dehydrogenation; the ruthenium catalyst was the most active in this reaction.
- Minami, Ichiro,Shimizu, Isao,Tsuji, Jiro
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- Hydrogen-transfer reduction of carbonyl compounds promoted by nickel nanoparticles
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Nickel(0) nanoparticles, generated from nickel(II) chloride, lithium powder and a catalytic amount of 4,4-di-tert-butylbiphenyl (DTBB) in THF at room temperature, have been found to promote the reduction of a variety of ketones and aldehydes by transfer hydrogenation using isopropanol as the hydrogen donor. The nickel nanoparticles were characterised and could be re-utilised with a good performance in the absence of a base. A mechanistic study demonstrates that the reaction proceeds through a dihydride-type mechanism.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
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- Redox-active ligand based Mn(i)-catalyst for hydrosilylative ester reduction
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Herein a Mn(i) catalyst bearing a redox-active phenalenyl (PLY) based ligand is reported for the efficient hydrosilylation of esters to alcohols using the inexpensive silane source polymethylhydrosiloxane (PMHS) under mild conditions. Mechanistic investigations suggest a strong ligand-metal cooperation where a ligand-based single electron transfer (SET) process initiates the reaction through Si-H bond activation.
- Chakraborty, Soumi,Das, Arpan,Mandal, Swadhin K.
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supporting information
p. 12671 - 12674
(2021/12/04)
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- Ambient-pressure highly active hydrogenation of ketones and aldehydes catalyzed by a metal-ligand bifunctional iridium catalyst under base-free conditions in water
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A green, efficient, and high active catalytic system for the hydrogenation of ketones and aldehydes to produce corresponding alcohols under atmospheric-pressure H2 gas and ambient temperature conditions was developed by a water-soluble metal–ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(OH)][Na] in water without addition of a base. The catalyst exhibited high activity for the hydrogenation of ketones and aldehydes. Furthermore, it was worth noting that many readily reducible or labile functional groups in the same molecule, such as cyan, nitro, and ester groups, remained unchanged. Interestingly, the unsaturated aldehydes can be also selectively hydrogenated to give corresponding unsaturated alcohols with remaining C=C bond in good yields. In addition, this reaction could be extended to gram levels and has a large potential of wide application in future industrial.
- Wang, Rongzhou,Yue, Yuancheng,Qi, Jipeng,Liu, Shiyuan,Song, Ao,Zhuo, Shuping,Xing, Ling-Bao
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- Method for synthesizing primary alcohol in water phase
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The invention discloses a method for synthesizing primary alcohol in a water phase. The method comprises the following steps: taking aldehyde as a raw material, selecting water as a solvent, and carrying out catalytic hydrogenation reaction on the aldehyde in the presence of a water-soluble catalyst to obtain the primary alcohol, wherein the catalyst is a metal iridium complex [Cp*Ir(2,2'-bpyO)(OH)][Na]. Water is used as the solvent, so that the use of an organic solvent is avoided, and the method is more environment-friendly; the reaction is carried out at relatively low temperature and normal pressure, and the reaction conditions are mild; alkali is not needed in the reaction, so that generation of byproducts is avoided; and the conversion rate of the raw materials is high, and the yield of the obtained product is high. The method not only has academic research value, but also has a certain industrialization prospect.
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Paragraph 0042-0043
(2021/07/14)
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- CeO2-nanocubes as efficient and selective catalysts for the hydroboration of carbonyl groups
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The CeO2-nanoparticle catalysed hydroboration of carbonyl compounds with HBpin (pin = OCMe2CMe2O) is reported to afford the corresponding borate esters in excellent yield. A series of aromatic and aliphatic aldehydes and ketones having synthetically important functional groups were well-Tolerated under mild reaction conditions. Further, chemoselective hydroboration of aldehydes over other reducible functional groups such as ketone, nitrile, hydroxide, alkene, alkyne, amide, ester, nitro, and halides was achieved. Importantly the catalyst can be recycled up to ten runs with slight loss in activity. This journal is
- Bhawar, Ramesh,Bose, Shubhankar Kumar,Patil, Kiran S.
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p. 15028 - 15034
(2021/09/04)
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- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
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- Photocatalytic synthesis of phenols mediated by visible light using KI as catalyst
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A transition-metal-free hydroxylation of iodoarenes to afford substituted phenols is described. The reaction is promoted by KI under white LED light irradiation and uses atmospheric oxygen as oxidant. By the use of triethylamine as base and solvent, the corresponding phenols are obtained in moderate to good yields. Mechanistic studies suggest that KI and catalysis synergistically promote the cleavage of C-I bond to form free aryl radicals.
- Huiqin, Wei,Wu, Mei
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supporting information
(2021/11/30)
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- Chemoselective Cleavage of Si-C(sp3) Bonds in Unactivated Tetraalkylsilanes Using Iodine Tris(trifluoroacetate)
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Organosilanes are synthetically useful reagents and precursors in organic chemistry. However, the typical inertness of unactivated Si-C(sp3) bonds under conventional reaction conditions has hampered the application of simple tetraalkylsilanes in organic synthesis. Herein we report the chemoselective cleavage of Si-C(sp3) bonds of unactivated tetraalkylsilanes using iodine tris(trifluoroacetate). The reaction proceeds smoothly under mild conditions (-50 °C to room temperature) and tolerates various polar functional groups, thus enabling subsequent Tamao-Fleming oxidation to provide the corresponding alcohols. NMR experiments and density functional theory calculations on the reaction indicate that the transfer of alkyl groups from Si to the I(III) center and the formation of the Si-O bond proceed concertedly to afford an alkyl-λ3-iodane and silyl trifluoroacetate. The developed method enables the use of unactivated tetraalkylsilanes as highly stable synthetic precursors.
- Matsuoka, Keitaro,Komami, Narumi,Kojima, Masahiro,Mita, Tsuyoshi,Suzuki, Kimichi,Maeda, Satoshi,Yoshino, Tatsuhiko,Matsunaga, Shigeki
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supporting information
p. 103 - 108
(2021/01/13)
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- Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
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The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
- Lambert, Tristan H.,Steiniger, Keri A.
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supporting information
p. 8013 - 8017
(2021/10/25)
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- Enantiomeric synthesis of natural alkylglycerols and their antibacterial and antibiofilm activities
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Alkylglycerols (AKGs) are bioactive natural compounds that vary by alkyl chain length and degree of unsaturation, and their absolute configuration is 2S. Three AKGs (5l–5n) were synthesised in enantiomerically pure form, and were characterised for the first time together with 12 other known and naturally occurring AKGs (5a–5k, 5o). Their structures were established using 1H and 13C APT NMR with 2D-NMR, ESI-MS or HRESI-MS and optical rotation data, and they were tested for their antibacterial and antibiofilm activities. AKGs 5a–5m and 5o showed activity against five clinical isolates and P. aeruginosa ATCC 15442, with MIC values in the range of 15–125 μg/mL. In addition, at half of the MIC, most of the AKGs reduced S. aureus biofilm formation in the range of 23%–99% and P. aeruginosa ATCC 15442 biofilm formation in the range of 14%–64%. The antibiofilm activity of the AKGs assessed in this work had not previously been studied.
- Fernández Montoya, Deicy J.,Contreras Jordan, Luis A.,Moreno-Murillo, Bárbara,Silva-Gómez, Edelberto,Mayorga-Wandurraga, Humberto
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supporting information
p. 2544 - 2550
(2019/11/13)
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- Selective Production of Linear Aldehydes and Alcohols from Alkenes using Formic Acid as Syngas Surrogate
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Performing carbonylation without the use of carbon monoxide for high-value-added products is an attractive yet challenging topic in sustainable chemistry. Herein, effective methods for producing linear aldehydes or alcohols selectively with formic acid as both carbon monoxide and hydrogen source have been described. Linear-selective hydroformylation of alkenes proceeds smoothly with up to 88 % yield and >30 regioselectivity in the presence of single Rh catalyst. Strikingly, introducing Ru into the system, the dual Rh/Ru catalysts accomplish efficient and regioselective hydroxymethylation in one pot. The present processes utilizing formic acid as syngas surrogate operate simply under mild condition, which opens a sustainable way for production of linear aldehydes and alcohols without the need for gas cylinders and autoclaves. As formic acid can be readily produced via CO2 hydrogenation, the protocols represent indirect approaches for chemical valorization of CO2.
- Chen, Junjun,Hua, Kaimin,Liu, Xiaofang,Deng, Yuchao,Wei, Baiyin,Wang, Hui,Sun, Yuhan
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p. 9919 - 9924
(2021/05/31)
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- Synthesis and surface-active properties of novel cleavable gemini surfactants
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A novel series of quaternary ammonium gemini compounds having a butynylene spacer and different hydrocarbon chain lengths (CGBu8-16) were prepared. Carbonate group inserted between the hydrocarbon chains and the polar heads make these compounds hydrolyzable. The degradation under hydrolysis of these novel series will lead to the generation of fatty alcohols and readily degradable compounds. The reagents used are biodegradable, renewable, or reusable. The surface activities and foamability in aqueous solution of the cleavable gemini compounds containing n-octyl, n-decyl, and n-dodecyl chains meet the criteria for being good surfactants and showed stable foams even at low concentrations.
- Gilbert, Elangeni Ana,Guastavino, Javier Fernando,Murguía, Marcelo César
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- Hydrosilylation of Esters Catalyzed by Bisphosphine Manganese(I) Complex: Selective Transformation of Esters to Alcohols
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Selective and efficient hydrosilylations of esters to alcohols by a well-defined manganese(I) complex with a commercially available bisphosphine ligand are described. These reactions are easy alternatives for stoichiometric hydride reduction or hydrogenation, and employing cheap, abundant, and nonprecious metal is attractive. The hydrosilylations were performed at 100 °C under solvent-free conditions with low catalyst loading. A large variety of aromatic, aliphatic, and cyclic esters bearing different functional groups were selectively converted into the corresponding alcohols in good yields.
- Bagh, Bidraha,Behera, Rakesh R.,Ghosh, Rahul,Khamari, Subrat,Panda, Surajit
-
supporting information
p. 3642 - 3648
(2020/04/20)
-
- Synthesis of Branched Biolubricant Base Oil from Oleic Acid
-
The mature manufacturing of synthetic lubricants (poly-α-olefins, PAO) proceeds through oligomerization, polymerization, and hydrogenation reactions of petrochemical ethylene. In this work, we utilize the inexpensive bio-derived oleic acid as raw material to synthesize a crotch-type C45 biolubricant base oil via a full-carbon chain synthesis without carbon loss. It contains several cascade chemical processes: oxidation of oleic acid to azelaic acid (further esterification to dimethyl azelate) and nonanoic acid (both C9 chains). The latter is then selectively hydrogenated to nonanol and brominated to the bromo-Grignard reagent. In a next step, a C45 biolubricant base oil is formed by nucleophilic addition (NPA) of excessive C9 bromo-Grignard reagent with dimethyl azelate, followed by subsequent hydrodeoxygenation. The specific properties of the prepared biolubricant base oil are almost equivalent to those of the commercial lubricant PAO6 (ExxonMobil). This process provides a new promising route for the production of value-added biolubricant base oils.
- Chen, Shuang,Wu, Tingting,Zhao, Chen
-
p. 5516 - 5522
(2020/09/07)
-
- Engineering carboxylic acid reductase for selective synthesis of medium-chain fatty alcohols in yeast
-
Medium-chain fatty alcohols (MCFOHs, C6 to C12) are potential substitutes for fossil fuels, such as diesel and jet fuels, and have wide applications in various manufacturing processes. While today MCFOHs are mainly sourced from petrochemicals or plant oils, microbial biosynthesis represents a scalable, reliable, and sustainable alternative. Here, we aim to establish a Saccharomyces cerevisiae platform capable of selectively producing MCFOHs. This was enabled by tailoring the properties of a bacterial carboxylic acid reductase from Mycobacterium marinum (MmCAR). Extensive protein engineering, including directed evolution, structure-guided semirational design, and rational design, was implemented. MmCAR variants with enhanced activity were identified using a growth-coupled high-throughput screening assay relying on the detoxification of the enzyme’s substrate, medium-chain fatty acids (MCFAs). Detailed characterization demonstrated that both the specificity and catalytic activity of MmCAR was successfully improved and a yeast strain harboring the best MmCAR variant generated 2.8-fold more MCFOHs than the strain expressing the unmodified enzyme. Through deletion of the native MCFA exporter gene TPO1, MCFOH production was further improved, resulting in a titer of 252 mg/L for the final strain, which represents a significant improvement in MCFOH production in minimal medium by S. cerevisiae.
- Hu, Yating,Zhu, Zhiwei,Gradischnig, David,Winkler, Margit,Nielsen, Jens,Siewers, Verena
-
p. 22974 - 22983
(2020/10/02)
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- Fluorescent and Biocompatible Ruthenium-Coordinated Oligo(p-phenylenevinylene) Nanocatalysts for Transfer Hydrogenation in the Mitochondria of Living Cells
-
It is challenging to design metal catalysts for in situ transformation of endogenous biomolecules with good performance inside living cells. Herein, we report a multifunctional metal catalyst, ruthenium-coordinated oligo(p-phenylenevinylene) (OPV-Ru), for intracellular catalysis of transfer hydrogenation of nicotinamide adenine dinucleotide (NAD+) to its reduced format (NADH). Owing to its amphiphilic characteristic, OPV-Ru possesses good self-assembly capability in water to form nanoparticles through hydrophobic interaction and π–π stacking, and numerous positive charges on the surface of nanoparticles displayed a strong electrostatic interaction with negatively charged substrate molecules, creating a local microenvironment for enhancing the catalysis efficiency in comparison to dispersed catalytic center molecule (TOF value was enhanced by about 15 fold). OPV-Ru could selectively accumulate in the mitochondria of living cells. Benefiting from its inherent fluorescence, the dynamic distribution in cells and uptake behavior of OPV-Ru could be visualized under fluorescence microscopy. This work represents the first demonstration of a multifunctional organometallic complex catalyzing natural hydrogenation transformation in specific subcellular compartments of living cells with excellent performance, fluorescent imaging ability, specific mitochondria targeting and good chemoselectivity with high catalysis efficiency.
- Chen, Yanyan,Dai, Nan,Liu, Libing,Lv, Fengting,Qi, Ruilian,Wang, Shu,Zhao, Hao
-
supporting information
(2020/03/23)
-
- Pd catalysts supported on dual-pore monolithic silica beads for chemoselective hydrogenation under batch and flow reaction conditions
-
Two different types of palladium catalysts supported on dual-pore monolithic silica beads [5% Pd/SM and 0.25% Pd/SM(sc)] for chemoselective hydrogenation were developed. Alkyne, alkene, azide, and nitro functionalities and the aromatic N-Cbz protecting group were chemoselectively hydrogenated using 5% Pd/SM. On the other hand, 0.25% Pd/SM(sc) showed unique and higher hydrogenation catalyst activity toward a wide variety of reducible functionalities. Furthermore, the catalyst activities of both 5% Pd/SM and 0.25% Pd/SM(sc) under flow hydrogenation conditions were also evaluated. A pre-packed 5% Pd/SM cartridge could be used continuously for at least 72 h without any loss of catalyst activity. The 0.2% Pd/SM(sc) catalyst prepacked in a cartridge showed high catalyst activity for the flow hydrogenation of trisubstituted alkenes under mild reaction conditions. This journal is
- Yamada, Tsuyoshi,Ogawa, Aya,Masuda, Hayato,Teranishi, Wataru,Fujii, Akiko,Park, Kwihwan,Ashikari, Yosuke,Tomiyasu, Noriyuki,Ichikawa, Tomohiro,Miyamoto, Riichi,Bai, Hongzhi,Matsuyama, Kiyoshi,Nagaki, Aiichiro,Sajiki, Hironao
-
p. 6359 - 6367
(2020/11/03)
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- Method for preparing alcohol and phenol through aerobic hydroxylation reaction of boric acid derivative in absence of photocatalyst
-
The invention discloses a method for preparing alcohol and phenol through aerobic hydroxylation reaction of a boric acid derivative in the absence of a photocatalyst, wherein the boric acid derivativeis aryl boronic acid or alkyl boronic acid, and the corresponding target compounds are respectively a phenol-based compound and an alcohol-based compound. According to the method, by using a boric acid derivative as a reaction substrate, an additive is added under a solvent condition, and a hydroxylation reaction is performed under aerobic and illumination conditions to obtain a corresponding target compound. According to the invention, the new strategy is provided for the synthesis of phenols through aerobic hydroxylation of aryl boronic acid without a photocatalyst; the catalyst-free aerobic hydroxylation method for photocatalysis of aryl boronic acid or alkyl boronic acid by using triethylamine as an additive is firstly disclosed; and the new method has advantages of photocatalyst-freecondition, wide substrate range and good functional group compatibility.
- -
-
Paragraph 0025-0028; 0030-0032
(2020/01/25)
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- Ruthenium-catalyzed hydrogenation of CO2as a route to methyl esters for use as biofuels or fine chemicals
-
A novel robust diphosphine-ruthenium(ii) complex has been developed that can efficiently catalyze both the hydrogenation of CO2 to methanol and its in situ condensation with carboxylic acids to form methyl esters; a TON of up to 3260 is achievable for the CO2 to methanol step. Both aromatic and aliphatic carboxylic acids can be transformed to their corresponding methyl esters with high conversion and selectivity (17 aliphatic and 18 aromatic examples). On the basis of a series of experiments, a mechanism has been proposed to account for the various steps involved in the catalytic pathway. More importantly, this approach provides a promising route for using CO2 as a C1 source for the production of biofuels, fine chemicals and methanol.
- Li, Yong,Liu, Qingbin,Ma, Yanping,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Zhang, Qiuyue,Zhao, Ziwei,Zhong, Yanxia
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p. 6766 - 6774
(2020/08/25)
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- Iridium Complex-Catalyzed C2-Extension of Primary Alcohols with Ethanol via a Hydrogen Autotransfer Reaction
-
The development of a C2-extension of primary alcohols with ethanol as the C2 source and catalysis by [Cp*IrCl2]2 (where Cp? = pentamethylcyclopentadiene) is described. This new extension system was used for a range of benzylic alcohol substrates and for aliphatic alcohols with ethanol as an alkyl reagent to generate the corresponding C2-extended linear alcohols. Mechanistic studies of the reaction by means of intermediates and deuterium labeling experiments suggest the reaction is based on hydrogen autotransfer.
- Kobayashi, Masaki,Itoh, Satoshi,Yoshimura, Keisuke,Tsukamoto, Yuya,Obora, Yasushi
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p. 11952 - 11958
(2020/10/23)
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- Novel clamp metal complex and application thereof
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The invention discloses a method for preparing a novel clamp-shaped complex and application of the novel clamp-shaped complex in the reaction of catalytic hydrogenation of carboxylic acid ester compounds to produce corresponding alcohols and reaction of carbon dioxide catalytic hydrogenation to form formamide compounds. Carboxylic acid esters and hydrogen as raw materials or carbon dioxide, hydrogen and amine compounds as raw materials are reacted in an organic solvent condition or a solvent-free condition in the presence of a transition metal complex as a catalyst to respectively form the corresponding alcohol compounds and/or corresponding formamide compounds. The method has the advantages of being high in reaction efficiency, good in selectivity, mild in conditions, economical, environmentally-friendly, and simple in operation, and has good promotion and application prospects.
- -
-
Paragraph 0410-0412; 0426-0429
(2019/04/26)
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- Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
- -
-
Paragraph 0301-0303; 0305
(2019/11/04)
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- Method for preparing fatty alcohols with same carbon number by catalytic hydrodeoxygenation from fatty acid and/or fatty acid ester
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The invention provides a method for preparing fatty alcohols with the same carbon number by catalytic hydrodeoxygenation from fatty acid and/or fatty acid ester. The method comprises the following step: in a reaction vessel, carrying out hydrodeoxygenation reaction on the fatty acid and/or fatty acid ester and hydrogen in the presence of a catalyst at a low temperature of 100-240 DEG C and under alow hydrogen pressure of 0.1-5 MPa to obtain desired fatty alcohol products with the same carbon number. According to the invention, the fatty alcohols with the same carbon number is prepared from the fatty acid and/or fatty acid ester through an active metal modified MeaXbAlc composite catalyst as defined herein. The method has the advantages of high conversion rate, good selectivity, mild reaction conditions, stable catalyst and the like, and has quite good industrial application prospect.
- -
-
Paragraph 0060; 0061; 0062; 0067; 0068; 0086; 0088; 0090
(2019/05/08)
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- Dehydroalkylative Activation of CNN- A nd PNN-Pincer Ruthenium Catalysts for Ester Hydrogenation
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Ruthenium-pincer complexes bearing CNN- A nd PNN-pincer ligands with diethyl-or diisopropylamino side groups, which have previously been reported to be active precatalysts for ester hydrogenation, undergo dehydroalkylation on heating in the presence of tricyclohexylphosphine to release ethane or propane, giving five-coordinate ruthenium(0) complexes containing a nascent imine functional group. Ethane or propane is also released under the conditions of catalytic ester hydrogenation, and time-course studies show that this release is concomitant with the onset of catalysis. A new PNN-pincer ruthenium(0)-imine complex is a highly active catalyst for ester hydrogenation at room temperature, giving up to 15500 turnovers with no added base. This complex was shown to react reversibly at room temperature with two equivalents of hydrogen to give a ruthenium(II)-dihydride complex, where the imine functionality has been hydrogenated to give a protic amine side group. These observations have potentially broad implications for the identities of catalytic intermediates in ester hydrogenation and related transformations.
- He, Tianyi,Buttner, John C.,Reynolds, Eamon F.,Pham, John,Malek, Jack C.,Keith, Jason M.,Chianese, Anthony R.
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supporting information
p. 17404 - 17413
(2019/11/03)
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- Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
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Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
- Barman, Milan K.,Das, Kuhali,Maji, Biplab
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p. 1570 - 1579
(2019/01/30)
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- Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
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Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
- Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
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p. 283 - 288
(2019/09/30)
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- Ambient-pressure hydrogenation of ketones and aldehydes by a metal-ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(H2O)] without using base
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An efficient catalytic system for hydrogenation of ketones and aldehydes using a Cp*Ir complex [Cp*Ir(2,2′-bpyO)(H2O)] bearing a bipyridine-based functional ligand as catalyst has been developed. A wide variety of secondary and primary alcohols were synthesized by the catalyzed hydrogenation of ketones and aldehydes under facile atmospheric-pressure without a base. The catalyst also displays an excellent chemoselectivity towards other carbonyl functionalities and unsaturated motifs. This catalytic system exhibits high activity for hydrogenation of ketones and aldehydes with H2 gas.
- Wang, Rongzhou,Qi, Jipeng,Yue, Yuancheng,Lian, Zhe,Xiao, Haibin,Zhuo, Shuping,Xing, Lingbao
-
-
- Photoinduced Hydroxylation of Organic Halides under Mild Conditions
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Presented in this paper is photoinduced hydroxylation of organic halides, providing a mild access to a range of functionalized phenols and aliphatic alcohols. These reactions generally proceed under mild reaction conditions with no need for a photocatalyst or a strong base and show a wide substrate scope as well as excellent functional group tolerance. This work highlights the unique role of NaI that allows a challenging transformation to proceed under mild reaction conditions.
- Cai, Yue-Ming,Xu, Yu-Ting,Zhang, Xin,Gao, Wen-Xia,Huang, Xiao-Bo,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
-
supporting information
p. 8479 - 8484
(2019/10/16)
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- Oxidative Deprotection of p-Methoxybenzyl Ethers via Metal-Free Photoredox Catalysis
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An efficient and greener deprotection method for p-methoxybenzyl (PMB) ethers using a metal-free visible light photoredox catalyst and air and ammonium persulfate as the terminal oxidants is presented. Various functional groups and protecting groups were tolerated in the developed method to achieve good to excellent yields in short reaction times. Significantly, the developed method was compatible with PMB ethers derived from primary, secondary, and tertiary alcohols and a gram-scale reaction. Mechanistic studies support a proposed reaction mechanism that involves single electron oxidation of the PMB ether.
- Ahn, Deok Kyun,Kang, Young Woo,Woo, Sang Kook
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p. 3612 - 3623
(2019/03/11)
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- Photoinduced hydroxylation of arylboronic acids with molecular oxygen under photocatalyst-free conditions
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Photoinduced hydroxylation of boronic acids with molecular oxygen under photocatalyst-free conditions is reported, providing a green entry to a variety of phenols and aliphatic alcohols in a highly concise fashion. This new protocol features photocatalyst-free conditions, wide substrate scope and excellent functional group compatibility.
- Xu, Yu-Ting,Li, Chen-Yuan,Huang, Xiao-Bo,Gao, Wen-Xia,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
-
supporting information
p. 4971 - 4975
(2019/09/30)
-
- Phthalocyanine Zinc-catalyzed Hydroxylation of Aryl Boronic Acids under Visible Light
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A visible-light-promoted aerobic oxidative hydroxylation of boronic acids using phthalocyanine zinc as an easily available photosensitizer has been developed. It provided a direct access to synthesize aliphatic alcohols and phenols from boronic acids. The advantages of this approach included the low catalyst loading (0.5 mol%), high efficient, the use of O2 as an oxygen source, wide substrate range, the simple operational process, and mild conditions. (Figure presented.).
- Luo, Dong-Ping,Huang, Yang-Feng,Hong, Xiao-Yi,Chen, Dingben,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Liu, Miao-Chang,Zhou, Yun-Bing,Wu, Hua-Yue
-
supporting information
p. 961 - 964
(2019/01/25)
-
- Unexpected CNN-to-CC Ligand Rearrangement in Pincer-Ruthenium Precatalysts Leads to a Base-Free Catalyst for Ester Hydrogenation
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We report the conversion of a series of CNN-pincer-ruthenium complexes Ru(CNN)HCl(CO) to a CC-chelated form Ru(CC)(PR3)2H(CO) on reaction with sodium tert-butoxide and monodentate phosphines. When the phosphine is triphenylphosphine, cis-phosphine complexes form at room temperature, which convert to the trans isomer at elevated temperatures. When the phosphine is tricyclohexylphosphine, only the trans-phosphine isomer is observed. The CC-chelated complexes are active catalysts for the hydrogenation of esters, without the need for added base. The ligand structure-activity relationship in the series of CC-chelated complexes mirrors that in the precursor CNN-Ru complexes, potentially indicating a common catalytic mechanism. Density functional theory calculations establish a plausible mechanism for the CNN-to-CC rearrangement and demonstrate that this rearrangement is potentially reversible under the conditions of ester hydrogenation catalysis.
- Le, Linh,Liu, Jiachen,He, Tianyi,Malek, Jack C.,Cervarich, Tia N.,Buttner, John C.,Pham, John,Keith, Jason M.,Chianese, Anthony R.
-
-
- Hydrofunctionalization of Olefins to Higher Aliphatic Alcohols via Visible-Light Photocatalytic Coupling
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Abstract: An atomically economical green protocol for the hydrofunctionalization of olefins to higher aliphatic alcohols with 100% anti-Markovnikov regioselectivity was developed via visible-light photocatalytic coupling. This method employs cheap, readily available and abundant methanol as both the C1 feedstock and the hydrogen source under visible light irradiation over CdS photocatalyst. A wide scope of olefin substrates could be hydrofunctionalized successfully to the corresponding higher alcohols with high selectivity. Besides alcohol, acetone and acetonitrile can also couple with olefins to generate the corresponding hydrofunctionalization products, suggesting promising potential industrial application. Graphical Abstract: [Figure not available: see fulltext.] Hydrofunctionalization of olefins to value-added chemicals with high selectivity was achieved via visible-light photocatalytic cross-coupling.
- Bao, Jingxian,Fan, Yonghui,Zhang, Shuyi,Zhong, Liangshu,Wu, Minghong,Sun, Yuhan
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-
- Lewis acid-catalyzed annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones: Synthesis of analogues of tolterodine, RORγ inhibitors and a GPR40 agonist
-
A beguiling annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones catalyzed by Lewis acid (BF3·OEt2) has been developed. The reaction involves two molecules of 3-aryloxyacrylate, resulting in the loss of one propiolate molecule to furnish 4-arylchroman-2-one, an important structural motif found in many natural products. This methodology has been elaborated to synthesize analogues of tolterodine, RORγ inhibitors and a GPR40 agonist.
- Kunkalkar, Rupesh A.,Fernandes, Rodney A.
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p. 2313 - 2316
(2019/02/27)
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- Method used for reduction of tertiary amide into alcohols and/or amines
-
The invention discloses a method used for reduction of tertiary amide into alcohols and/or amines. The method comprises following steps: tertiary amide, an alkali metal reagent, and a proton donor agent are added into an organic solvent for a following reaction selectively: when the proton donor agent is a raw material alcohol and/or inorganic salt aqueous solution, the reaction product is an alcohol compound and/or tertiary amine compound. The method is capable of realizing selective reduction of tertiary amide into alcohols and tertiary amine compounds, the yield is high, the suitable rangeis wide, operation is safe and simple, the adopted raw materials are cheap and easily available; no precious metal catalyst, toxic silanes, and flammable and combustible metal hydrides are adopted; notoxic by product is generated; reaction is more friendly to the environment; problems in the prior art that amide compound reducing method operation is complex, conditions are strict, and control ofproducts is difficult are solved.
- -
-
Paragraph 0163-0166
(2019/08/07)
-
- Mechanistic study of the selective hydrogenation of carboxylic acid derivatives over supported rhenium catalysts
-
The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are not accompanied by reduction of aromatic moieties. A Re loading amount of 5 wt% and a catalyst pretreatment with H2 at 500 °C were identified as being optimal to obtain the highest catalytic activity for the hydrogenation processes. The results of studies using various characterization methods, including X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM), indicate that the Re species responsible for the catalytic hydrogenation processes have sub-nanometer to a few nanometer sizes and average oxidation states higher than 0 and below +4. The presence of either a carboxylic acid and/or its corresponding alcohol is critical for preventing the Re/TiO2 catalyst from promoting production of dearomatized byproducts. Although Re/TiO2 is intrinsically capable of hydrogenating aromatic rings, carboxylic acids, alcohols, amides, and amines strongly adsorb on the Re species, which leads to suppression of this process. Moreover, the developed catalytic system was applied to selective hydrogenation of triglycerides that form the corresponding alcohols.
- Toyao, Takashi,Ting, Kah Wei,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Maeno, Zen,Ariga-Miwa, Hiroko,Kanda, Yasuharu,Asakura, Kiyotaka,Shimizu, Ken-ichi
-
p. 5413 - 5424
(2019/10/29)
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- Molecular Catalysts for Selective Hydrogenolysis of Amides
-
A compound by the name 1,1,1-tris(di(3,5-dimethoxyphenyl)phosphino-methyl)ethane. The compound can be represented by the structure of formula (I): The compound is useful as a ligand for ruthenium to form an organometallic complex. The complex is an active catalyst for the hydrogenolysis of amides to form amines and optionally alcohols.
- -
-
Paragraph 0081-0082
(2019/11/22)
-
- Discovery and Comparison of Homogeneous Catalysts in a Standardized HOT-CAT Screen with Microwave-Heating and qNMR Analysis: Exploring Catalytic Hydration of Alkynes
-
A HOT-CAT (homogeneous thermal catalysis) screen using microwave-heating and quantitative NMR (qNMR) analysis has been developed for identification and comparison of catalyst activity in homogeneous metal-based catalysis. The hydration of terminal alkynes to ketones or aldehydes served as a model reaction in this proof-of-concept study. Key aspects of the screen are the use of a high-temperature setting (e. g., 160 °C) at a fixed, short reaction time (e. g., 15 min) for all samples. Analysis of crude reaction mixtures by a standardized, quantitative 1H NMR protocol gives a comprehensive picture of catalyst chemo- and regioselectivity, which permits broad comparisons and the discovery of non-target reactivity. For catalytic alkyne hydration, data for 105 runs involving 81 catalyst systems with 15 different metals is presented. The activity of all established catalyst systems was reproduced, and new catalyst systems with Markovnikov hydration selectivity were discovered and applied to preparative runs, namely Cu2O?CSA (CSA=camphorsulfonic acid), Co(OAc)2?tetraphenylporphyrin?CSA and [IrCl(COD)]?CSA.
- Brunner, Andreas,Hintermann, Lukas,Milzarek, Tobias M.,Schreyer, Matthias,Wegmann, Marcus
-
-
- Study of Precatalyst Degradation Leading to the Discovery of a New Ru0 Precatalyst for Hydrogenation and Dehydrogenation
-
The complex Ru-MACHO (1) is a widely used precatalyst for hydrogenation and dehydrogenation reactions under basic conditions. In an attempt to identify the active catalyst form, 1 was reacted with a strong base. The formation of previously unreported species was observed by NMR and mass spectrometry. This observation indicated that complex 1 quickly degraded under basic conditions when no substrate was present. X-ray crystallography enabled the identification of three complexes as products of this degradation of complex 1. These complexes suggested degradation pathways which included ligand cleavage and reassembly, along with reduction of the ruthenium atom. One of the decomposition products, the Ru0 complex [Ru(N(CH2CH2PPh2)3)CO] (5), was prepared independently and studied. 5 was found to be active, entirely additive-free, in the acceptorless dehydrogenation of aliphatic alcohols to esters. The hydrogenation of esters catalyzed by 5 was also demonstrated under base-free conditions with methanol as an additive. Protic substrates were shown to add reversibly to complex 5, generating RuII-hydrido species, thus presenting a rare example of reversible oxidative addition from Ru0 to RuII and reductive elimination from RuII to Ru0.
- Anaby, Aviel,Schelwies, Mathias,Schwaben, Jonas,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
-
supporting information
p. 2193 - 2201
(2018/07/25)
-
- Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
-
The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
- Ullrich, Johannes,Breit, Bernhard
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p. 785 - 789
(2018/02/14)
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- Robust cobalt oxide catalysts for controllable hydrogenation of carboxylic acids to alcohols
-
The selective catalytic hydrogenation of carboxylic acids is an important process for alcohol production, while efficient heterogeneous catalyst systems are still being explored. Here, we report the selective hydrogenation of carboxylic acids using earth-abundant cobalt oxides through a reaction-controlled catalysis process. The further reaction of the alcohols is completely hindered by the presence of carboxylic acids in the reaction system. The partial reduction of cobalt oxides by hydrogen at designated temperatures can dramatically enhance the catalytic activity of pristine samples. A wide range of carboxylic acids with a variety of functional groups can be converted to the corresponding alcohols at a yield level applicable to large-scale production. Cobalt monoxide was established as the preferred active phase for the selective hydrogenation of carboxylic acids.
- Song, Song,Wang, Dong,Di, Lu,Wang, Chuanming,Dai, Weili,Wu, Guangjun,Guan, Naijia,Li, Landong
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p. 250 - 257
(2018/02/20)
-
- A Co2B Mediated NaBH4 Reduction Protocol Applicable to a Selection of Functional Groups in Organic Synthesis
-
A high-yielding and high-rate reduction method that operates with alkenes, alkynes, azides, nitriles, and nitroarenes was developed and optimized. The method makes use of sodium borohydride reduction of CoSO4 under release of hydrogen along with the formation of Co2B as a nanoparticle material. The produced Co2B activates the various functional groups for hydride reduction. The protocol was proven to operate with an assortment of functional groups to provide good to excellent yields. Furthermore, the reduction method was successfully adapted, implemented, and developed for a continuous flow approach using the multi-jet oscillating disk (MJOD) flow reactor platform at atmospheric pressure.
- Lundevall, Frida Johanne,Elumalai, Vijayaragavan,Drageset, Audun,Totland, Christian,Bj?rsvik, Hans-René
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supporting information
p. 3416 - 3425
(2018/07/29)
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- OPEN-FLASK HYDROBORATION AND THE USE THEREOF
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The present disclosure generally relates to a process for hydroboration of an alkene or alkyne using ammonia borane (AB). In particular, the present invention relates to hydroboration of an alkene or alkyne in the presence of air or moisture, and a clean process for facile preparation of an alcohol by oxidizing the organoborane so formed with hydrogen peroxide. The products, including aminodialkylboranes, ammonia trialkylborane complexes, as well as various alcohols so prepared, are within the scope of this disclosure.
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Paragraph 0046; 0058; 0059
(2018/03/25)
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- Carbonyl and ester C-O bond hydrosilylation using κ4-diimine nickel catalysts
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The synthesis of alkylphosphine-substituted α-diimine (DI) ligands and their subsequent addition to Ni(COD)2 allowed for the preparation of (iPr2PPrDI)Ni and (tBu2PPrDI)Ni. The solid state structures of both compounds were found to feature a distorted tetrahedral geometry that is largely consistent with the reported structure of the diphenylphosphine-substituted variant, (Ph2PPr DI)Ni. To explore and optimize the synthetic utility of this catalyst class, all three compounds were screened for benzaldehyde hydrosilylation activity at 1.0 mol% loading over 3 h at 25 °C. Notably, (Ph2PPr DI)Ni was found to be the most efficient catalyst while phenyl silane was the most effective reductant. A broad scope of aldehydes and ketones were then hydrosilylated, and the silyl ether products were hydrolyzed to afford alcohols in good yield. When attempts were made to explore ester reduction, inefficient dihydrosilylation was noted for ethyl acetate and no reaction was observed for several additional substrates. However, when an equimolar solution of allyl acetate and phenyl silane was added to 1.0 mol% (Ph2PPr DI)Ni, complete ester C-O bond hydrosilylation was observed within 30 min at 25 °C to generate propylene and PhSi(OAc)3. The scope of this reaction was expanded to include six additional allyl esters, and under neat conditions, turnover frequencies of up to 990 h-1 were achieved. This activity is believed to be the highest reported for transition metal-catalyzed ester C-O bond hydrosilylation. Proposed mechanisms for (Ph2PPr DI)Ni-mediated carbonyl and allyl ester C-O bond hydrosilylation are also discussed.
- Rock, Christopher L.,Groy, Thomas L.,Trovitch, Ryan J.
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supporting information
p. 8807 - 8816
(2018/07/13)
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- Efficient hydroboration of carbonyls by an iron(II) amide catalyst
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An easily prepared iron(ii) amide precatalyst enables the selective hydroboration of carbonyls with HBpin (pinacolborane) in the absence of any additive. The reactions proceed with low catalytic loading (1-3 mol%) under mild reaction conditions and display wide functional group compatibility. Aldehydes are selectively hydroborated in the presence of other reducible functional groups, such as ketones, alkenes, nitriles, esters, amides, acids and halides.
- Baishya, Ashim,Baruah, Swavalina,Geetharani
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p. 9231 - 9236
(2018/07/29)
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- Reduction and Reductive Deuteration of Tertiary Amides Mediated by Sodium Dispersions with Distinct Proton Donor-Dependent Chemoselectivity
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A practical and scalable single electron transfer reduction mediated by sodium dispersions has been developed for the reduction and reductive deuteration of tertiary amides. The chemoselectivity of this method highly depends on the nature of the proton donor. The challenging reduction via C-N bond cleavage has been achieved using Na/EtOH, affording alcohol products, while the use of Na/NaOH/H2O leads to the formation of amines via selective C-O scission. Sodium dispersions with high specific surface areas are crucial to obtain high yields and good chemoselectivity. This new method tolerates a range of tertiary amides. Moreover, the corresponding reductive deuterations mediated by Na/EtOD-d1 and Na/NaOH/D2O afford useful α,α-dideuterio alcohols and α,α-dideuterio amines with an excellent deuterium content.
- Zhang, Bin,Li, Hengzhao,Ding, Yuxuan,Yan, Yuhao,An, Jie
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p. 6006 - 6014
(2018/05/24)
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- New boron reagents for cycloboration of α-olefins into boriranes under Cp2TiCl2 catalysis
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The one-pot cycloboration of α-olefins (oct-1-ene, dec-1-ene) for a facile access to substituted boriranes has been carried out with the use of alkyl, arylalkyl, and cycloalkyl boron dichlorides (EtBCl2, n-PentBCl2, n-HexBCl2, Ph(CH2)2BCl2, cyclo-OctBCl2, 2-norbornylBCl2) under Cp2TiCl2 catalysis.
- Khusainova, Liliya I.,Khafizova, Leila O.,Tyumkina, Tatyana V.,Ryazanov, Kirill S.,Popodko, Natalya R.,Dzhemilev, Usein M.
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- An original catalytic synthesis of boriran-1-ols
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2-Alkylboriran-1-ols were obtained in a one-pot process by hydrolysis of 1-fluoro- and 1-chloroboriranes in 90–92% yield. The starting 1-haloboriranes were generated by cycloboration of α-olefins with BCl3·SMe2 or BF3·THF in the presence of Mg metal (acceptor of halogen ions) and Cp2TiCl2 catalyst.
- Khafizova, Leila O.,Khusainova, Liliya I.,Tyumkina, Tat'yana V.,Ryazanov, Kirill S.,Popod'ko, Natal'ya R.,Dzhemilev, Usein M.
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p. 577 - 578
(2018/12/13)
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- A Practical and Chemoselective Ammonia-Free Birch Reduction
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A novel protocol for a significantly improved, practical, and chemoselective ammonia-free Birch reduction mediated by bench-stable sodium dispersions and recoverable 15-crown-5 ether is reported. A broad range of aromatic and heteroaromatic compounds is reduced with excellent yields.
- Lei, Peng,Ding, Yuxuan,Zhang, Xiaohe,Adijiang, Adila,Li, Hengzhao,Ling, Yun,An, Jie
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supporting information
p. 3439 - 3442
(2018/06/26)
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