- Mild Selective Deoxygenation of Amine Oxides by Tin-Tin Bonded Derivatives
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A new method of deoxygenation of amine oxides with tin reagent is proposed.It utilizes the reductive properties of the tin-tin bond in hexabutyldistannane or 1,2-dichlorotetrabutyldistannane.Oxides of tertiary amines are reduced into amines by hexabutyldistannane in high yields, whereas pyridine N-oxides react cleanly with 1,2-dichlorotetrabutyldistannane to give the corresponding pyridines.These reactions occur under mild conditions and are very selective.
- Jousseaume, Bernard,Chanson, Evelyne
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- Hydrolysis of nicotinyl 6-aminonicotinate
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The degradation kinetics of nicotinyl 6-aminonicotinate in aqueous buffer solutions were studied over the pH range from 4.0 to 10.0. In all cases, pseudo-first-order kinetics were observed at constant hydronium ion concentration. The pH-rate profile indic
- Wang,Patel
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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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- Towards practical earth abundant reduction catalysis: Design of improved catalysts for manganese catalysed hydrogenation
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Manganese catalysts derived from tridentate P,N,N ligands can be activated easily using weak bases for both ketone and ester hydrogenations. Kinetic studies indicate the ketone hydrogenations are 0th order in acetophenone, positive order in hydrogen and 1st order in the catalyst. This implies that the rate determining step of the reaction was the activation of hydrogen. New ligand systems with varying donor strength were studied and it was possible to make the hydrogen activation significantly more efficient; a catalyst displaying around a 3-fold increase in initial turn-over frequencies for the hydrogenation of acetophenone relative to the parent system was discovered as a result of these kinetic investigations. Ester hydrogenations and ketone transfer hydrogenation (isopropanol as reductant) are first order for both the substrate and catalysts. Kinetic studies also gained insight into catalyst stability and identified a working range in which the catalyst is stable throughout the catalytic reaction (and a larger working range where high yields can still be achieved). The new more active catalyst, combining an electron-rich phosphine with an electron-rich pyridine is capable of hydrogenating acetophenone using as little as 0.01 mol% catalyst at 65 °C. In all, protocols for reduction of 21 ketones and 15 esters are described.
- Widegren, Magnus B.,Clarke, Matthew L.
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- REDUCTION WITH POLYMER-BOUND NADH MODELS.
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We have performed numerous reductions with a NADH model grafted on a Merrifield resin.The yields are generally excellent and in all cases always superior to those obtained with "free" models.
- Dupas, G.,Bourguignon, J.,Ruffin, C.,Queguiner, G.
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- Air-stable gold nanoparticles ligated by secondary phosphine oxides for the chemoselective hydrogenation of aldehydes: Crucial role of the ligand
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The synthesis of air-stable and homogeneous gold nanoparticles (AuNPs) employing tert-butyl(naphthalen-1-yl)phosphine oxide as supporting ligand is described via NaBH4 reduction of a Au(I) precursor, [(tert-butyl(naphthalen-1-yl)phosphine oxide)AuCl]2. This highly reproducible and simple procedure furnishes small (1.24 ± 0.16 nm), highly soluble nanoparticles that are found to be highly active catalysts for the hydrogenation of substituted aldehydes, giving high conversions and chemoselectivities for a wide variety of substrates. In addition to catalytic studies the role of the novel stabilizer in the remarkable activity and selectivity exhibited by this system was interrogated thoroughly using a wide range of techniques, including ATR FT-IR, HRMAS NMR, XPS, and EDX spectroscopy. In particular, isotopic labeling experiments enabled us to probe the coordination mode adopted by the SPO ligand bound to the nanoparticle surface by ATR FT-IR spectroscopy. In combination with a series of control experiments we speculate that the SPO ligand demonstrates ligand-metal cooperative effects and plays a seminal role in the heterolytic hydrogenation mechanism.
- Cano, Israel,Chapman, Andrew M.,Urakawa, Atsushi,Van Leeuwen, Piet W. N. M.
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- Partial photocatalytic oxidations of 3-pyridinemethanol and 3-picoline by TiO2 prepared in HCl, HNO3 and H2SO4 at different temperatures
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Home prepared TiO2 photocatalysts were prepared from TiCl4 precursor in the absence and presence of HCl (1?6 M), HNO3 (1 M) or H2SO4 (1 M) at room temperature (RT), 60 or 100 °C. The TiO2 catalysts were characterised by XRD, BET, SEM and TGA techniques. TiO2 catalyst could not form at low temperature (up to 60 °C) in the presence of H2SO4. Just rutile phase was obtained for all TiO2 samples prepared at RT and 60 °C in HCl or HNO3. At 100 °C mainly both brookite and rutile phases were obtained in the presence of HCl or HNO3, whilst mainly anatase phase appeared in the presence of H2SO4. Nanorod structured TiO2 was formed in the presence of 1 M HCl or HNO3 at RT and 60 °C. The prepared TiO2 catalysts were used for partial oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 in water under UVA irradiation. Moreover, photocatalytic oxidation of 3-picoline, precursor of 3-pyridinemethanol, was also performed, but much lower product selectivity values were obtained with respect to 3-pyridinemethanol oxidation. However, selective 3-picoline oxidation could be performed at pH 2 with low activity. Degussa P25 was used for comparison and almost all home prepared catalysts showed a higher selectivity, but they showed to be less active than Degussa P25. The high selectivity of the home prepared samples was not due to the type of TiO2 phase, but mainly to the hydrophilicity of the TiO2 surface which allowed desorption of valuable products instead of their over-oxidation.
- ?etinkaya, S?d?ka,Yurdakal, Sedat
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- Silver-catalyzed hydrogenation of aldehydes in water
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Silver bullet: The first silver-catalyzed hydrogenation in water was developed. A silver complex containing a bulky monodentate phosphine ligand was used to generate alcohols from a broad range of aldehydes, including aliphatic, aromatic, and heterocyclic aldehydes. This method provides a direct and efficient route to alcohols from aldehydes and opens a new avenue in silver catalysis. Copyright
- Jia, Zhenhua,Zhou, Feng,Liu, Mingxin,Li, Xingshu,Chan, Albert S. C.,Li, Chao-Jun
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- Synthesis of 1,5-bis(triphenylphosphonium)pentan-3-ol dichloride and its application to the preparation of 1,7-di(pyridin-3-yl)heptan-4-ol
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The preparation of 1,7-di(pyridin-3-yl)-heptan-4-ol (1), an important intermediate in the synthesis of a series of novel cancer multidrug resistance (CMR) chemosensitizers, has been accomplished in high overall yield via the new bis-Wittig reagent 1,5-bis(triphenylphosphonium)pentan-3-ol dichloride (6), that can also be used in the preparation of other members of the class of CMRs.
- Stivanello, Mariano,Leoni, Lucia,Bortolaso, Roberto
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- Highly dispersed ruthenium hydroxide supported on titanium oxide effective for liquid-phase hydrogen-transfer reactions
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Supported ruthenium hydroxide catalysts (Ru(OH)x/support) were prepared with three different TiO2 supports (anatase TiO2 (TiO2(A), BET surface area: 316 m2g-1), anatase TiO2 (TiO2(B), 73m2 g-1), and rutile TiO2 (TiO2(C), 3.2 m2 g-1)), as well as an Al2O3 support (160 m2g -1). Characterizations with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and X-ray absorption fine structure (XAFS) showed the presence of monomeric ruthenium(III) hydroxide and polymeric ruthenium(III) hydroxide species. Judging from the coordination numbers of the nearest-neighbor Ru atoms and the intensities of the ESR signals, the amount of monomeric hydroxide species increased in the order of Ru(OH)x x/ TiO2(C) x/Al2O3 x/ TiO 2(B) x/TiO2(A). These supported ruthenium hydroxide catalysts, especially Ru(OH)x/TiO2(A), showed high catalytic activities and selectivities for liquid-phase hydrogen-transfer reactions, such as racemization of chiral secondary alcohols and the reduction of carbonyl compounds and allylic alcohols. The catalytic activities of Ru(OH)x/TiO2(A) for these hydrogen-transfer reactions were at least one order of magnitude higher than those of previously reported heterogeneous catalysts, such as Ru(OHx/Al2O 3. These catalyses were truly heterogeneous, and the catalysts recovered after the reactions could be reused several times without loss of catalytic performance. The reaction rates monotonically increased with an increase in the amount of monomeric ruthenium hydroxide species, which suggests that the monomeric species are effective for these hydrogen-transfer reactions.
- Yamaguchi, Kazuya,Koike, Takeshi,Kim, Jung Won,Ogasawara, Yoshiyuki,Mizuno, Noritaka
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- 4-Aza-N-benzyl bicyclo[2,2,2]octyl ammonium borohydride a highly chemoselective reagent for the reduction of aldehydes in the presence of ketones
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The title compound reduces aldehydes in the presence of ketones with high chemoselectivity in t-butanol under reflux condition in high yields.
- Firouzabadi,Afsharifar
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- Pyrimidine derivatives XII. A convenient preparation of 6-formylpyrimidinedione and 2- and 3-formylpyridine derivatives from corresponding nitrooxymethyl derivatives
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The convenient preparation of 6-formylpyrimipinedione derivatives and 2- and 3-formylpyridine are described. Thus, 5-bromo-1,3-dimethyl- (1a), 5-bromo-3-methyl-1-(2-nitrooxyethyl)- (1b), and 5-bromo-3-methyl-1-(3-nitrooxypropyl)-2,4(1H,3H)-pyrimidine-dione (1c) were converted to the corresponding 6-formyl compounds 2a, 2b, and 2c, respectively, in excellent yields by the reaction with triethylamine and 1,4-diazabicyclo[2.2.2]octane. These 6-formylpyrimidinedione derivatives are key intermediates for the preparation of 6-carbon-carbon substituted compounds, which are expected to be potential antitumor and antiviral agents. Similarly, 2-(and 3-)formylpyridine (9a (and 9b)) were obtained by the reaction of 2-(and 3)nitrooxymethylpyridine (8a (and 8b)) with 1,4-diazabicyclo[2.2.2]octane.
- Kinoshita,Ohishi
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- BIOMIMETIC REDUCTION WITH NON WATER-SENSITIVE NADH MODELS
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Two NADH models were synthesized which are considerably less water-sensitive than classical-1,4 dihydronicotinamide derivatives such as N-benzyl-1,4 dihydronicotinamide (BNAH): these two models are reactive and more stable in the presence of water than previously reported models.
- Cazin, J.,Dupas, G.,Bourguignon, J.,Queguiner, G.
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- Supported Rhodium Nanoparticles Catalyzed Reduction of Nitroarenes, Arylcarbonyls and Aryl/Benzyl Sulfoxides using Ethanol/Methanol as In Situ Hydrogen Source
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A facile reduction reaction of nitroarenes, aryl carbonyls and aryl/benzyl sulfoxides was performed under polystyrene supported rhodium (Rh@PS) catalyzed conditions using ethanol/methanol as in situ hydrogen source. The catalyst Rh@PS played a pivotal role in the oxidation of ethanol/methanol in the presence of traces of aerial oxygen and base to produce hydrogen gas, enough for further reduction reaction. Transmission electron microscopy (TEM) analysis indicated that the average particle size of the Rh nanoparticles (NPs) lies between 2–3 nm; this is responsible for its high catalytic activity. The advantages of Rh@PS are its catalytic activity, easy preparation, recovery, recyclability for several runs, and low metal leaching during reaction. (Figure presented.).
- Sharma, Saurabh,Bhattacherjee, Dhananjay,Das, Pralay
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- High-throughput synthesis and analysis of acylated cyanohydrins
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The yields and optical purities of products obtained from chiral Lewis acid/Lewis base-catalysed additions of ct-ketonitriles to prochiral aldehydes could be accurately determined by an enzymatic method. The amount of remaining aldehyde was determined after its reduction to an alcohol, whilst the two product enantiomers were analysed after subsequent hydrolysis first by the (S)-selective Candida antarctica lipase B and then by the unselective pig liver esterase. The method could be used for analysis of products obtained from a number of aromatic aldehydes and aliphatic ketonitriles. Microreactor technology was successfully combined with high-throughput analysis for efficient catalyst optimization.
- Hamberg, Anders,Lundgren, Stina,Wingstrand, Erica,Moberg, Christina,Hult, Karl
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- Organo-base mediated Cannizzaro reaction
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The organo-base, 1,1,3,3-tetramethylguanidine, mediates the Cannizzaro reaction of reactive aromatic aldehydes in water thus providing the corresponding alcohols and acids. Application of formaldehyde as a sacrificial aldehyde for the cross-Cannizzaro reaction is also presented.
- Basavaiah, Deevi,Sharada, Duddu S.,Veerendhar, Ainelly
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- Purification and characterization of an NADH-dependent alcohol dehydrogenase from Candida maris for the synthesis of optically active 1-(pyridyl)ethanol derivatives
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A novel (R)-specific alcohol dehydrogenase (AFPDH) produced by Candida maris IFO10003 was purified to homogeneity by ammonium sulfate fractionation, DEAE-Toyopearl, and Phenyl-Toyopearl, and characterized. The relative molecular mass of the native enzyme was found to be 59,900 by gel filtration, and that of the subunit was estimated to be 28,900 on SDS-polyacrylamide gel electrophoresis. These results suggest that the enzyme is a homodimer. It required NADH as a cofactor and reduced various kinds of carbonyl compounds, including ketones and aldehydes. AFPDH reduced acetylpyridine derivatives, β-keto esters, and some ketone compounds with high enantioselectivity. This is the first report of an NADH-dependent, highly enantioselective (R)-specific alcohol dehydrogenase isolated from a yeast. AFPDH is a very useful enzyme for the preparation of various kinds of chiral alcohols.
- Kawano, Shigeru,Yano, Miho,Hasegawa, Junzo,Yasohara, Yoshihiko
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- Synthetic scope and mechanistic studies of Ru(OH)x/Al 2O3-catalyzed heterogeneous hydrogen-transfer reactions
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Three kinds of hydrogen-transfer reactions, namely racemization of chiral secondary alcohols, reduction of carbonyl compounds to alcohols using 2-propanol as a hydrogen donor, and isomerization of allylic alcohols to saturated ketones, are efficiently promoted by the easily prepared and inexpensive supported ruthenium catalyst Ru(OH)x/Al2O 3. A wide variety of substrates, such as aromatic, aliphatic, and heterocyclic alcohols or carbonyl compounds, can be converted into the desired products, under anaerobic conditions, in moderate to excellent yields and without the need for additives such as bases. A larger scale, solvent-free reaction is also demonstrated: the isomerization of 1-octen-3-ol with a substrate/catalyst ratio of 20000/1 shows a very high turnover frequency (TOF) of 18400 h 1, with a turnover number (TON) that reaches 17200. The catalysis for these reactions is intrinsically heterogeneous in nature, and the Ru(OH)x/Al2O3 recovered after the reactions can be reused without appreciable loss of catalytic performance. The reaction mechanism of the present Ru(OH)x/Al2O 3-catalyzed hydrogentransfer reactions were examined with monodeuterated substrates. After the racemization of (S)-1-deuterio-1-phenylethanol in the presence of acetophenone was complete, the deuterium content at the α-position of the corresponding racemic alcohol was 91%, whereas no deuterium was incorporated into the α-position during the race mization of (S)-1-phenylethanol-OD. These results show that direct carbon-to-carbon hydrogen transfer occurs via a metal monohydride for the racemization of chiral secondary alcohols and reduction of carbonyl compounds to alcohols. For the isomerization, the α-deuterium of 3-deuterio-1-octen-3-ol was selectively relocated at the β-position of the corresponding ketones (99% D at the β-position), suggesting the involvement of a 1,4-addition of ruthenium monohydride species to the α,β-unsaturated ketone intermediate. The ruthenium monohydride species and the α,β-unsaturated ketone would be formed through alcoholate formation/β-elimination. Kinetic studies and kinetic isotope effects show that the Ru - H bond cleavage (hydride transfer) is included in the rate-determining step.
- Yamaguchi, Kazuya,Koike, Takeshi,Kotani, Miyuki,Matsushita, Mitsunori,Shinachi, Satoshi,Mizuno, Noritaka
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- CALCIUM ALKOXYALANATES. III. REDUCTION OF ORGANIC FUNCTIONAL GROUPS BY CALCIUM TETRAKIS(ALKOXY)ALANATES
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Calcium tetrakis(alkoxy)alanates obtained from different alcohols reduce aldehydes, ketones, acids, esters, acid chlorides and anhydrides to alcohols in high yields.Good results are achieved in the reduction of amides to amines.The reductions of nitrile and oxime groups and dehalogenation reactions are more difficult.Selectivity is possible in the reduction of organic epoxides.
- Cucinella, S.,Dozzi, G.,Bruzzone, M.
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- Deoxygenation of pyridine N-oxides by palladium-catalysed transfer oxidation of trialkylamines
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A convenient and chemoselective method for deoxygenation of pyridine TV-oxide derivatives by transfer oxidation of triethylamine-catalysed by [Pd(OAc)2]/dppf is described.
- Fuentes, José A.,Clarke, Matthew L.
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- Microwave-heated γ-Alumina Applied to the Reduction of Aldehydes to Alcohols
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The development of cheap and robust heterogeneous catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction is desirable due to the difficulties in product isolation and catalyst recovery associated with the traditional use of homogeneous catalysts for MPV. Herein, we show that microwave heated γ-Al2O3 can be used for the reduction of aldehydes to alcohols. The reaction is efficient and has a broad substrates scope (19 entries). The products can be isolated by simple filtration, and the catalyst can be regenerated. With the use of microwave heating, we can direct the heating to the catalyst rather than to the whole reaction medium. Furthermore, DFT was used to study the reaction mechanism, and we can conclude that a dual-site mechanism is operative where the aldehyde and 2-propoxide are situated on two adjacent Al sites during the reduction. Additionally, volcano plots were used to rationalize the reactivity of Al2O3 in comparison to other metal oxides.
- Dhokale, Bhausaheb,Susarrey-Arce, Arturo,Pekkari, Anna,Runemark, August,Moth-Poulsen, Kasper,Langhammer, Christoph,H?relind, Hanna,Busch, Michael,Vandichel, Matthias,Sundén, Henrik
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- Iron-catalyzed reduction of aromatic aldehydes with paraformaldehyde and H2O as the hydrogen source
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In this Letter, we report a novel, general, convenient, and inexpensive method for the reduction of aromatic aldehydes to the corresponding benzylic alcohols. Various aromatic aldehydes were reduced in good to excellent yields by using well-defined iron-complex as the catalyst precursor and using paraformaldehyde and water as the hydrogen source.
- Natte, Kishore,Li, Wanfang,Zhou, Shaolin,Neumann, Helfried,Wu, Xiao-Feng
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- Uncatalyzed Meerwein-Ponndorf-Oppenauer-Verley Reduction of Aldehydes and Ketones under Supercritical Conditions
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When a solution of a carbonyl compound in alcohol (primary or secondary) is heated to ca. 300 °C, a disproportionation reaction, in which a carbonyl compound is reduced to the corresponding alcohol and the alcohol is oxidized to the corresponding ketone, takes place. This uncatalyzed variation of the Meerwein-Ponndorf-Oppenauer-Verley reaction gives, in certain cases, e.g., reduction of acetophenone or benzaldehyde by i-PrOH, almost quantitative yields. Yields are higher with secondary alcohols such as i-PrOH than with a primary alcohol such as EtOH. The reactions were also performed in a flow system by passing at a slow rate the same solutions through a glass or a metal coil heated to elevated temperatures. Ab initio calculations performed at the B3LYP/6-31G* level show that thermodynamically i-PrOH is a more potent reducing agent than EtOH by ca. 4 kcal/mol. The computations also show that in cases of aromatic carbonyl compounds, part of the deriving force is obtained from the entropy change of the reaction. The major contributor to the high yield, however, is the excess alcohol used, which shifts the equilibrium to the right. Calculated entropy of activation as well as isotopic H/D labeling suggest a cyclic transition state.
- Sominsky, Lena,Rozental, Esther,Gottlieb, Hugo,Gedanken, Aharon,Hoz, Shmaryahu
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- Hydrosilylation of Aldehydes and Ketones Catalyzed by a 2-Iminopyrrolyl Alkyl-Manganese(II) Complex
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A well-defined and very active single-component manganese(II) catalyst system for the hydrosilylation of aldehydes and ketones is presented. First, the reaction of 5-(2,4,6-iPr3C6H2)-2-[N-(2,6-iPr2C6H3)formimino]pyrrolyl potassium (KL) and [MnCl2(Py)2] afforded the binuclear 2-iminopyrrolyl manganese(II) pyridine chloride complex [Mn2{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}2(Py)2(μ-Cl)2] 1. Subsequently, the alkylation reaction of complex 1 with LiCH2SiMe3 afforded the respective (trimethylsilyl)methyl-Mn(II) complex [Mn{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}(Py)CH2SiMe3] 2 in a good yield. Complexes 1 and 2 were characterized by elemental analysis, 1H NMR spectroscopy, Evans' method, FTIR spectroscopy, and single-crystal X-ray diffraction. While the crystal structure of complex 1 has been identified as a binuclear entity, in which the Mn(II) centers present pentacoordinate coordination spheres, that of complex 2 corresponds to a monomer with a distorted tetrahedral coordination geometry. Complex 2 proved to be a very active precatalyst for the atom-economic hydrosilylation of several aldehydes and ketones under very mild conditions, with a maximum turnover frequency of 95 min-1, via a silyl-Mn(II) mechanistic route, as asserted by a combination of experimental and theoretical efforts, the respective silanes were cleanly converted to the respective alcoholic products in high yields.
- Cruz, Tiago F. C.,Veiros, Luís F.,Gomes, Pedro T.
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p. 1195 - 1206
(2022/01/11)
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- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
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Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
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p. 803 - 808
(2021/07/20)
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- Na2S·9H2O mediated facile synthesis of 1,3-dihydrofuro[3,4-b]quinoline derivatives via domino reduction approach
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A simple, highly efficient method for synthesis of 1,3-dihydrofuro[3,4-b]quinoline is described by the reaction of o-arylalkynyl quinoline aldehydes with Na2S·9H2O via domino reduction approach. The method is simple and proceeds under mild condition under an air atmosphere to give 1,3-dihydrofuro[3,4-b]quinoline in good to excellent yields. The beauty of the reaction is cyclization as well as reduction has been taken place in the same reaction pot. Also the conversion of aldehyde into primary alcohol has been discussed under the same reaction condition.
- Singh, Rashmi,Gupta, Tanu,Sharma, Vishal Prasad,Singh, Radhey M.,Tewari, Ashish Kumar
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supporting information
(2021/09/22)
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- Iron-catalyzed chemoselective hydride transfer reactions
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A Diaminocyclopentadienone iron tricarbonyl complex has been applied in chemoselective hydrogen transfer reductions. This bifunctional iron complex demonstrated a broad applicability in mild conditions in various reactions, such as reduction of aldehydes over ketones, reductive alkylation of various functionalized amines with functionalized aldehydes and reduction of α,β-unsaturated ketones into the corresponding saturated ketones. A broad range of functionalized substrates has been isolated in excellent yields with this practical procedure.
- Coufourier, Sébastien,Ndiaye, Daouda,Gaillard, Quentin Gaignard,Bettoni, Léo,Joly, Nicolas,Mbaye, Mbaye Diagne,Poater, Albert,Gaillard, Sylvain,Renaud, Jean-Luc
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supporting information
(2021/06/07)
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- Manganese-catalysed transfer hydrogenation of esters
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Manganese catalysed ester reduction using ethanol as a hydrogen transfer agent in place of dihydrogen is reported. High yields can be achieved for a range of substrates using 1 mol% of a Mn(i) catalyst, with an alkoxide promoter. The catalyst is derived from a tridentate P,N,N ligand.
- Oates, Conor L.,Widegren, Magnus B.,Clarke, Matthew L.
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supporting information
p. 8635 - 8638
(2020/08/21)
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- Synthesis method of 3-chloromethylpyridine hydrochloride
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The invention belongs to the field of organic chemistry, and specifically relates to a synthesis method of 3-chloromethylpyridine hydrochloride. The synthesis method comprises the following steps: (1)taking 3-methylpyridine as a raw material and water as a solvent, oxidizing 3-methylpyridine into 3-picolinic acid by potassium permanganate, wherein the molar ratio of 3-methylpyridine to potassiumpermanganate is 1: (2.1-2.3); maintaining the oxidation temperature in a range of 85-90 DEG C, heating for 30 minutes, adjusting the reaction liquid to be acidic after the reaction is finished, and then cooling and filtering to obtain 3-picolinic acid; (2) generating methyl 3-picolinate from 3-picolinic acid and methanol under an acidic condition, wherein the molar ratio of 3-picolinic acid to methanol is 1: 1.3; (3) reducing methyl 3-picolinate into 3-pyridylcarbinol; and (4) reacting the 3-pyridylcarbinol with thionyl chloride to obtain the target product 3-chloromethylpyridine hydrochloride, wherein the molar ratio of the 3-pyridylcarbinol to the thionyl chloride is 1: (1.1-1.3).
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Paragraph 0020; 0023; 0025; 0028; 0030; 0033
(2020/05/05)
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- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
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A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
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supporting information
p. 12411 - 12414
(2020/10/30)
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- Reduction of Aldehydes with Formic acid in Ethanol using Immobilized Iridium Nanoparticles on a Triazine-phosphanimine Polymeric Organic Support
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A novel triazine-phosphanimine polymeric organic support (TPA) was synthesized successfully by a controllable one-pot method using melamine (1,3,5-triazine-2,4,6-triamine) and trichlorophosphane (PCl3). The TPA substrate is a material incorporating P and N atoms which can coordinate with metals as a pincer ligand to stabilize them, providing an efficient heterogeneous support to prepare recyclable transition metal catalyst systems. In this study, TPA was used as support to immobilize iridium nanoparticles in the range of ~8 nm on its surface, resulting in the generation of a novel iridium nanocatalyst system (INP-TPA-POP). This catalyst system was characterized using different microscopic and spectroscopic techniques such as FT-IR, TEM, XPS, XRD, SEM, EDX, elemental analysis, ICP and BET analysis. The INP-TPA-POP nanocatalyst exhibited remarkable activity in reduction of aldehydes to alcohols using formic acids as reducing agent in ethanol as solvent.
- Panahi, Farhad,Haghighi, Fatemeh,Khalafi-Nezhad, Ali
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- Cyclopentadienone iron tricarbonyl complexes-catalyzed hydrogen transfer in water
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The development of efficient and low-cost catalytic systems is important for the replacement of robust noble metal complexes. The synthesis and application of a stable, phosphine-free, water-soluble cyclopentadienone iron tricarbonyl complex in the reduction of polarized double bonds in pure water is reported. In the presence of cationic bifunctional iron complexes, a variety of alcohols and amines were prepared in good yields under mild reaction conditions.
- Coufourier, Sébastien,Gaillard, Sylvain,Mbaye, Mbaye Diagne,Ndiaye, Daouda,Renaud, Jean-Luc
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supporting information
(2020/01/28)
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- A facile and highly efficient transfer hydrogenation of ketones and aldehydes catalyzed by palladium nanoparticles supported on mesoporous graphitic carbon nitride
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A novel transfer hydrogenation methodology for the reduction of ketones (14 examples) and benzaldehyde derivatives (12 examples) to the corresponding alcohols using Pd nanoparticles supported on mesoporous graphitic carbon nitride (mpg-C3N4/Pd) as a reusable catalyst and ammonia borane as a safe hydrogen source in an aqueous solution MeOH/H2O (v/v = 1/1) is described. The catalytic hydrogenation reactions were conducted in a commercially available high-pressure glass tube at room temperature, and the corresponding alcohols were obtained in high yields in 2–5 min. Moreover, the presented transfer hydrogenation protocol shows partial halogen selectivity with bromo-, fluoro-, and chloro-substituted carbonyl analogs. In addition, the present catalyst can be reused up to five times without losing its efficiency, and scaling-up the reaction enables α-methylbenzyl alcohol to be produced in 90% isolated yield.
- Ni?anc?, Bilal,Da?alan, Ziya
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- A 3 - chloromethyl pyridine hydrochloride synthetic method
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The invention belongs to the field of organic chemistry, and in particular relates to a 3 - chloromethyl pyridine hydrochloride synthetic method, comprises the following steps: (1) to 3 - methyl pyridine as raw materials, takes water as a solvent, the potassium permanganate oxide it to 3 - pyridine carboxylic acid, wherein 3 - methyl pyridine with potassium permanganate in a molar ratio of 1: 2.1 - 2.3, the oxidation temperature to maintain the 85 - 90 °C, heating 30 min, the reaction end the reaction liquid is adjusted to be acidic, and then cooling and filtering to obtain 3 - pyridine carboxylic acid; (2) 3 - pyridine carboxylic acid with methanol under acidic conditions to produce the 3 - pyridine carboxylic acid methyl ester, wherein the 3 - pyridine carboxylic acid with methanol in a molar ratio of 1: 1.3; (3) reducing 3 - pyridine carboxylic acid methyl ester as the 3 - pyridine methanol; (4) 3 - pyridine methanol with thionyl chloride reaction to obtain the target product 3 - chloromethyl pyridine hydrochloride, 3 - pyridine methanol with thionyl chloride in a molar ratio of 1: 1.1 - 1.3.
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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.
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Paragraph 0301-0303; 0306
(2019/11/04)
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- Iron catalysed selective reduction of esters to alcohols
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The reaction of (dppBIAN)FeCl2 with 3 equivalents of n-BuLi affords a catalytically active anionic Fe complex; the nature of the anionic complex was probed using EPR and IR experiments and is proposed to involve a dearomatized, radical, ligand scaffold. This complex is an active catalyst for the hydrosilylation of esters to afford alcohols; loadings as low as 1 mol% were employed.
- Tamang, Sem Raj,Cozzolino, Anthony F.,Findlater, Michael
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supporting information
p. 1834 - 1838
(2019/02/20)
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- Olefin-tethered organoruthenium carbene complexes: Synthesis, X-ray structure and catalytic insights on hydrogenation of esters
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A series of Ru(II) complexes encompassing imidazolylidene olefin arm have been designed. The newly synthesized ligands and complexes were fully characterized by 1H, 13C NMR, and elemental analyses. Structural geometry for one of the envoy Ru(II) carbene complexes 3a was confirmed by single-crystal X-ray diffraction studies. The complexes acquired a distorted octahedral geometry. The highly active [Ru(II)-NHC] complex 3b, showed excellent catalytic performance for the hydrogenation of esters in 1,4-dioxane medium. The effects of solvent, base, wingtip substituents, time and catalyst loading were also investigated. The reported catalyst performed exceptionally well for a range of esters and furnishes very good yield of hydrogenated products.
- Nirmala, Muthukumaran,Murugan, Kaliyappan,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy,Bertani, Roberta,Malecki, Jan Grzegorz
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- Borohydride reduction stabilizing system and method for reducing ester into alcohol
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The invention provides a borohydride reduction stabilizing system and a method for reducing ester into alcohol. The borohydride reduction stabilizing system comprises a borohydride reducing agent anda stabilizer for stabilizing the borohydride reducing agent, wherein the borohydride reducing agent is sodium borohydride or potassium borohydride, and the stabilizer is an alkali metal salt of alcohol. On the basis of an existing sodium borohydride/potassium reducing agent, an alcohol alkali metal salt (such as sodium alcoholate or potassium alcoholate) is added, and then the sodium borohydride/potassium reducing agent can keep stable and is not decomposed under a heating condition, so that on one hand, reduction activity is maintained in a relatively high state and the situation of excessiveuse is reduced, and on the other hand, generation of hydrogen is reduced and the process risk is reduced.
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Paragraph 0119; 0120; 0121
(2019/09/13)
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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.
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Paragraph 0410-0412; 0499-0502
(2019/04/26)
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- General and Phosphine-Free Cobalt-Catalyzed Hydrogenation of Esters to Alcohols
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Catalytic hydrogenation of esters is essential for the sustainable production of alcohols in organic synthesis and chemical industry. Herein, we describe the first non-noble metal catalytic system that enables an efficient hydrogenation of non-activated esters to alcohols in the absence of phosphine ligands (with a maximum turnover number of 2391). The general applicability of this protocol was demonstrated by the high-yielding hydrogenation of 39 ester substrates including aromatic/aliphatic esters, lactones, polyesters and various pharmaceutical molecules.
- Shao, Zhihui,Zhong, Rui,Ferraccioli, Raffaella,Li, Yibiao,Liu, Qiang
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supporting information
p. 1125 - 1130
(2019/10/22)
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- Catalytic Hydrogenation of Carboxamides with a Bifunctional Cp Ru Catalyst Bearing an Imidazol-2-ylidene with a Protic Aminoethyl Side Chain
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Synthesis of a Cp Ru complex bearing an NH 2 -functionalized N -heterocyclic carbene (C-N H) was achieved by treatment of CpRuBr(isoprene) with an equimolar amount of a silver complex, which was generated from Ag 2 O and 1-(2-aminoethyl)-3-methylimidazolium bromide, in CH 3 CN at room temperature. The new CpRuBr(C-N H) complex showed a higher catalytic performance than the related CpRuCl(P-N H) and CpRuCl(N-N H) complexes. In the reaction of N -arylcarboxamides, the amine products were obtained in satisfactory yields under mild temperature conditions.
- Ikariya, Takao,Kawano, Teruhiro,Kayaki, Yoshihito,Watari, Ryo
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p. 2542 - 2547
(2019/06/08)
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- The reductive deaminative conversion of nitriles to alcohols using: Para -formaldehyde in aqueous solution
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We report herein, for the first time, the application of para-formaldehyde (pFA) to the reductive deamination of both aliphatic and aromatic nitriles in aqueous solution under transfer hydrogenation conditions. A broad range of primary alcohols have been synthesized selectively with very good to excellent yields under the optimized conditions. The study disclosed that the air-stable, inexpensive and commercially available catalyst [Ru(p-cymene)Cl2]2 acts as the catalyst precursor in this reaction, converting to other more active catalytic species in the presence of pFA, resulting in its degradation to CO2 and H2. Nitriles are also showed to play a dual role in this transformation, both as a substrate and as a ligand, where the dimeric catalyst structures convert to monomeric ones upon the coordination of nitrile molecules.
- Tavakoli, Ghazal,Prechtl, Martin H. G.
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p. 6092 - 6101
(2019/11/11)
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- Aluminum Hydroxide Secondary Building Units in a Metal-Organic Framework Support Earth-Abundant Metal Catalysts for Broad-Scope Organic Transformations
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The intrinsic heterogeneity of alumina (Al2O3) surface presents a challenge for the development of alumina-supported single-site heterogeneous catalysts and hinders the characterization of catalytic species at the molecular level as well as the elucidation of mechanistic details of the catalytic reactions. Here we report the use of aluminum hydroxide secondary building units (SBUs) in the MIL-53(Al) metal-organic framework (MOF) with the formula Al(μ2-OH)(BDC) (BDC = 1,4-benzenedicarboxylate) as a uniform and structurally defined functional mimic of Al2O3 surface for supporting Earth-abundant metal (EAM) catalysts. The μ2-OH groups in MIL-53(Al) SBUs were readily deprotonated and metalated with CoCl2 and FeCl2 to afford MIL-53(Al)-CoCl and MIL-53(Al)-FeCl precatalysts which were characterized by powder X-ray diffraction, nitrogen sorption, elemental analysis, density functional theory, and extended X-ray fine structure spectroscopy. Activation with NaBEt3H converted MIL-53(Al)-CoCl to MIL-53(Al)-CoH which effectively catalyzed hydroboration of alkynes and nitriles and hydrosilylation of esters. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of AlIII and CoII centers in MIL-53(Al)-CoH while deuterium labeling studies suggested σ-bond metathesis as a key step for the MIL-53(Al)-CoH-catalyzed addition reactions. MIL-53(Al)-FeCl competently catalyzed oxidative Csp3-H amination and Wacker-type alkene oxidation. XANES analysis revealed the oxidation of FeII to FeIII centers in the activated MIL-53(Al)-FeCl catalyst and suggested that oxidative Csp3-H amination occurs via the formation of FeIII-OtBu species by single electron transfer between FeII centers in MIL-53(Al)-FeCl and (tBuO)2 with concomitant generation of 1 equiv of tBuO· radical, C-H activation through hydrogen atom abstraction to generate alkyl radicals, protonation of FeIII-OtBu by aniline to generate MIL-53(Al)-FeIII-anilide, and finally C-N coupling between the FeIII-anilide and alkyl radical to form the Csp3-H amination product and regenerate the FeII catalyst. These highly active single-site MOF-based solid catalysts were readily recovered and reused up to five times without significant decrease in catalytic activity. This work thus demonstrates the great potential of using the aluminum hydroxide SBUs in MOFs to support EAM catalysts for important organic transformations.
- Feng, Xuanyu,Ji, Pengfei,Li, Zhe,Drake, Tasha,Oliveres, Pau,Chen, Emily Y.,Song, Yang,Wang, Cheng,Lin, Wenbin
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p. 3327 - 3337
(2019/03/26)
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- A 3 - pyridine formaldehyde synthetic method
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The present invention relates to machine the chemical field, in particular to a 3 - pyridine formaldehyde synthetic method, comprises the following steps: 1, to 3 - methyl pyridine as raw materials, under acidic conditions, through the oxidation reaction
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Paragraph 0032; 0035; 0037; 0040; 0042; 0045
(2019/05/28)
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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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- Aryl Boronic Acid Catalysed Dehydrative Substitution of Benzylic Alcohols for C?O Bond Formation
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A combination of pentafluorophenylboronic acid and oxalic acid catalyses the dehydrative substitution of benzylic alcohols with a second alcohol to form new C?O bonds. This method has been applied to the intermolecular substitution of benzylic alcohols to form symmetrical ethers, intramolecular cyclisations of diols to form aryl-substituted tetrahydrofuran and tetrahydropyran derivatives, and intermolecular crossed-etherification reactions between two different alcohols. Mechanistic control experiments have identified a potential catalytic intermediate formed between the aryl boronic acid and oxalic acid.
- Estopi?á-Durán, Susana,Donnelly, Liam J.,Mclean, Euan B.,Hockin, Bryony M.,Slawin, Alexandra M. Z.,Taylor, James E.
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supporting information
p. 3950 - 3956
(2019/02/16)
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- Stabilization of NaBH4 in Methanol Using a Catalytic Amount of NaOMe. Reduction of Esters and Lactones at Room Temperature without Solvent-Induced Loss of Hydride
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Rapid reaction of NaBH4 with MeOH precludes its use as a solvent for large-scale ester reductions. We have now learned that a catalytic amount of NaOMe (5 mol %) stabilizes NaBH4 solutions in methanol at 25 °C and permits the use of these solutions for the reduction of esters to alcohols. The generality of this reduction method was demonstrated using 22 esters including esters of naturally occurring chiral γ-butyrolactone containing dicarboxylic acids. This method permits the chemoselective reductions of esters in the presence of cyano and nitro groups and the reductive cyclization of a pyrrolidinedione ester to a fused five-membered furo[2,3-b]pyrrole and a (-)-crispine A analogue in high optical and chemical yields. Lactones, aliphatic esters, aromatic esters containing electron-withdrawing groups, and heteroaryl esters are reduced more rapidly than aryl esters containing electron-donating groups. The 11B NMR spectrum of the NaOMe-stabilized NaBH4 solutions showed a minor quartet due to monomethoxyborohydride (NaBH3OMe) that persisted up to 18 h at 25 °C. We postulate that NaBH3OMe is probably the active reducing agent. In support of this hypothesis, the activation barrier for hydride transfer from BH3(OMe)- onto benzoic acid methyl ester was calculated as 18.3 kcal/mol.
- Prasanth,Joseph, Ebbin,Abhijith,Nair,Ibnusaud, Ibrahim,Raskatov, Jevgenij,Singaram, Bakthan
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p. 1431 - 1440
(2018/02/09)
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- Manganese Catalyzed Hydrogenation of Enantiomerically Pure Esters
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A manganese-catalyzed hydrogenation of esters has been accomplished with TONs up to 1000, using cheap, environmentally benign, potassium carbonate and simple alcohols as activator and solvent, respectively. The weakly basic conditions lead to good functional group tolerance and enable the hydrogenation of enantiomerically enriched α-chiral esters with essentially no loss of stereochemical integrity.
- Widegren, Magnus B.,Clarke, Matthew L.
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supporting information
p. 2654 - 2658
(2018/05/17)
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- Cobalt Pincer Complexes for Catalytic Reduction of Carboxylic Acid Esters
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A selection of cobalt(I) and cobalt(II) pincer type complexes with different substitution patterns was tested in the catalytic reduction of carboxylic acid esters to alcohols. The cobalt pincer type complex 4 is suitable for the hydrogenation of aromatic as well as aliphatic and cyclic esters. Mechanistic investigation indicated a metal ligand cooperated reaction pathway.
- Junge, Kathrin,Wendt, Bianca,Cingolani, Andrea,Spannenberg, Anke,Wei, Zhihong,Jiao, Haijun,Beller, Matthias
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supporting information
p. 1046 - 1052
(2018/01/01)
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- Study of Precatalyst Degradation Leading to the Discovery of a New Ru0 Precatalyst for Hydrogenation and Dehydrogenation
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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
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supporting information
p. 2193 - 2201
(2018/07/25)
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- Syntheses of hydrido selenophenolato iron(II) complexes and their catalytic application in hydrosilylation of aldehydes and ketones
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Three novel selenophenolato hydrido iron(II) complexes [cis-(H)(SeAr)Fe(PMe3)4] (4–6) (Ar=C6H5 (4), p-MeOC6H4 (5) and o-MeC6H4 (6)) were prepared through the reaction of Fe(PMe3)4 with selenophenols ArSeH (1–3) via Se–H activation. The iron hydrido complexes 4, 5 and 6 could catalyze the hydrosilylation of aldehydes and ketones. Among them complex 5 is the best catalyst for this process. Furthermore, α,β-unsaturated alcohols could be obtained from the selective reduction reactions of the corresponding α,β-unsaturated carbonyls catalyzed by hydrido iron(II) complex 5. This catalytic system has good tolerance for some common groups but it is easy to reduce the nitro group to an amino group. The experiments indicate that the chemoselectivity for this catalytic system is –CHO>–NO2>–C([dbnd]O)CH3. The crystal structure of 6 was determined by X-ray diffraction.
- Wang, Yangyang,Ren, Shishuai,Zhang, Wenbo,Xue, Benjing,Qi, Xinghao,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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- Switchable Chemoselective Transfer Hydrogenations of Unsaturated Carbonyls Using Copper(I) N-Donor Thiolate Clusters
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Unsaturated alcohols and saturated carbonyls are important chemical, pharmaceutical, and biochemical intermediates. We herein report an efficient transfer hydrogenation protocol in which conversion of unsaturated carbonyl compounds to either unsaturated alcohols or saturated carbonyls was catalyzed by Cu(I) N-donor thiolate clusters along with changing hydrogen source (isopropanol or butanol) and base (NaOH or K2CO3). Mechanistic studies supported by DFT transition state modeling indicate that such a chemoselectivity can be explained by the relative concentrations of Cu(I) monohydride and protonated Cu(I) hydride complexes in each catalytic system.
- Zhang, Meng-Juan,Tan, Da-Wei,Li, Hong-Xi,Young, David James,Wang, Hui-Fang,Li, Hai-Yan,Lang, Jian-Ping
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p. 1204 - 1215
(2018/02/09)
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- Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
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The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
- Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
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p. 3145 - 3157
(2018/06/01)
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- Photoinduced Electron Transfer (PET)-Mediated Fragmentation of Picolinium-Derived Redox Probes
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The photolysis of covalently linked N-alkyl picolinium phenylacetate—carbazole dyads was analyzed experimentally and by using density functional theory (DFT) and time dependent-DFT (TD-DFT) calculations. In contrast to earlier observations efficient one and two-photon fragmentations conditions were found for 15 c (δu=0.16 GM at 730 nm) opening the way for the design of a novel class of “caged” compounds.
- Dunkel, Petra,Barosi, Anna,Dhimane, Hamid,Maurel, Fran?ois,Dalko, Peter I.
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p. 12920 - 12931
(2018/08/11)
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- Diarylurea histone deacetylation enzyme inhibitor
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The invention belongs to the field of medical chemistry and particularly relates to a diarylurea histone deacetylation enzyme inhibitor, a medicine composition containing the histone deacetylation enzyme inhibitor, application of the inhibitor to preparat
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Paragraph 0119-0120
(2018/03/24)
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- RUTHENIUM COMPLEX, METHOD FOR PRODUCING SAME, AND USE OF SAME
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The present invention provides a novel ruthenium complex that is easy to produce and handle and that can be supplied relatively inexpensively, a method for producing this ruthenium complex, a method for producing alcohols and the like using this ruthenium complex as a catalyst, a method for producing carbonyl compounds using this ruthenium complex as a catalyst, and a method for producing N-alkylamine compounds using this ruthenium complex as a catalyst. The present invention pertains to a ruthenium complex represented by general formula (1) RuX1X2(PNP) (NHC)m(Solv)n(1) (in general formula (1), X1 and X2 each independently represent a monovalent anionic monodentate ligand; PNP represents a tridentate aminodiphosphine ligand, NHC represents an N-heterocyclic carbene derived from a nitrogen-containing heterocyclic ring, and Solv represents a coordinating solvent; and m represents an integer from 1 to 3, n represents an integer from 0 to 2, and 1≦m+n≦3.), a method for producing the same, a catalyst including the same, and methods for producing various organic compounds using this catalyst.
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Paragraph 0350; 0351
(2017/04/11)
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- Synthetic method of 3-pyridylaldehyde
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The invention relates to the field of organic chemistry, in particular to a synthetic method of 3-pyridylaldehyde. The synthetic method comprises the following steps: 1, taking 3-methyl pyridine as a raw material and obtaining 3-pyridine nitrogen oxide through oxidation reaction under an acidic condition; 2, synthesizing the 3-pyridine nitrogen oxide into acetic acid-3-pyridine methyl ester through acetic anhydride rearrangement; 3, hydrolyzing the acetic acid-3-pyridine methyl ester to obtain 3-pyridine methanol; 4, performing oxidation reaction on the 3-pyridine methanol to obtain 3-pyridylaldehyde. After the synthetic method is adopted, the 3-methyl pyridine is used as the raw material, and the 3-pyridine methanol is obtained through N-oxidation, rearrangement and hydrolyzation and is further oxidized to obtain the 3-pyridylaldehyde. The synthetic method provided by the invention is high in total yield, low in raw material price, short in reaction time, mild in condition, and simple in process operation.
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Paragraph 0032; 0035; 0040; 0045
(2017/11/18)
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- Efficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese-PNN pincer complex
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Novel well-defined NNP and PNP manganese pincer complexes have been synthetized and fully characterized. The catalyst Mn-2 containing an imidazolyaminolphosphino ligand shows high activity and selectivity in the hydrogenation of a wide range of secondary and tertiary amides to the corresponding alcohols and amines, under relatively mild conditions. For the first time, more challenging substrates like primary aromatic amides including an actual herbicide can also be hydrogenated using this earth-abundant metal-based pincer catalyst.
- Papa, Veronica,Cabrero-Antonino, Jose R.,Alberico, Elisabetta,Spanneberg, Anke,Junge, Kathrin,Junge, Henrik,Beller, Matthias
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p. 3576 - 3585
(2017/07/11)
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- Copper-Based Intermetallic Electride Catalyst for Chemoselective Hydrogenation Reactions
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The development of transition metal intermetallic compounds, in which active sites are incorporated in lattice frameworks, has great potential for modulating the local structure and the electronic properties of active sites, and enhancing the catalytic activity and stability. Here we report that a new copper-based intermetallic electride catalyst, LaCu0.67Si1.33, in which Cu sites activated by anionic electrons with low work function are atomically dispersed in the lattice framework and affords selective hydrogenation of nitroarenes with above 40-times higher turnover frequencies (TOFs up to 5084 h-1) than well-studied metal-loaded catalysts. Kinetic analysis utilizing isotope effect reveals that the cleavage of the H-H bond is the rate-determining step. Surprisingly, the high carrier density and low work function (LWF) properties of LaCu0.67Si1.33 enable the activation of hydrogen molecules with extreme low activation energy (Ea = 14.8 kJ·mol-1). Furthermore, preferential adsorption of nitroarenes via a nitro group is achieved by high oxygen affinity of LaCu0.67Si1.33 surface, resulting in high chemoselectivity. The present efficient catalyst can further trigger the hydrogenation of other oxygen-containing functional groups such as aldehydes and ketones with high activities. These findings demonstrate that the transition metals incorporated in the specific lattice site function as catalytically active centers and surpass the conventional metal-loaded catalysts in activity and stability.
- Ye, Tian-Nan,Lu, Yangfan,Li, Jiang,Nakao, Takuya,Yang, Hongsheng,Tada, Tomofumi,Kitano, Masaaki,Hosono, Hideo
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p. 17089 - 17097
(2017/12/06)
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- Reductive Bis-addition of Aromatic Aldehydes to α,β-Unsaturated Esters via the Use of Sm/Cu(I) in Air: A Route to the Construction of Furofuran Lignans
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The novel bis-addition of benzaldehydes to acrylates or maleates was achieved by the direct use of samarium metal with the assistance of CuI under mild conditions under dry air, and the useful 2-hydroxylalkyl-γ-butyrolactons and lignan derivatives were thus constructed with high efficiency. The key factors that influence the reaction efficiency were investigated. The use of potassium iodide and molecular sieves as additives can improve the reaction efficiency remarkably.
- Liu, Yongjun,Tian, Guang,Li, Jingjing,Qi, Yan,Wen, Yonghong,Du, Feng
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p. 5932 - 5939
(2017/06/07)
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- Mechanistic Investigation of Bis(imino)pyridine Manganese Catalyzed Carbonyl and Carboxylate Hydrosilylation
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We recently reported a bis(imino)pyridine (or pyridine diimine, PDI) manganese precatalyst, (Ph2PPrPDI)Mn (1), that is active for the hydrosilylation of ketones and dihydrosilylation of esters. In this contribution, we reveal an expanded scope for 1-mediated hydrosilylation and propose two different mechanisms through which catalysis is achieved. Aldehyde hydrosilylation turnover frequencies (TOFs) of up to 4900 min-1 have been realized, the highest reported for first row metal-catalyzed carbonyl hydrosilylation. Additionally, 1 has been shown to mediate formate dihydrosilylation with leading TOFs of up to 330 min-1. Under stoichiometric and catalytic conditions, addition of PhSiH3 to (Ph2PPrPDI)Mn was found to result in partial conversion to a new diamagnetic hydride compound. Independent preparation of (Ph2PPrPDI)MnH (2) was achieved upon adding NaEt3BH to (Ph2PPrPDI)MnCl2 and single-crystal X-ray diffraction analysis revealed this complex to possess a capped trigonal bipyramidal solid-state geometry. When 2,2,2-trifluoroacetophenone was added to 1, radical transfer yielded (Ph2PPrPDI·)Mn(OC·(Ph)(CF3)) (3), which undergoes intermolecular C-C bond formation to produce the respective Mn(II) dimer, [(μ-O,Npy-4-OC(CF3)(Ph)-4-H-Ph2PPrPDI)Mn]2 (4). Upon finding 3 to be inefficient and 4 to be inactive, kinetic trials were conducted to elucidate the mechanisms of 1- and 2-mediated hydrosilylation. Varying the concentration of 1, substrate, and PhSiH3 revealed a first order dependence on each reagent. Furthermore, a kinetic isotope effect (KIE) of 2.2 ± 0.1 was observed for 1-catalyzed hydrosilylation of diisopropyl ketone, while a KIE of 4.2 ± 0.6 was determined using 2, suggesting 1 and 2 operate through different mechanisms. Although kinetic trials reveal 1 to be the more active precatalyst for carbonyl hydrosilylation, a concurrent 2-mediated pathway is more efficient for carboxylate hydrosilylation. Considering these observations, 1-catalyzed hydrosilylation is believed to proceed through a modified Ojima mechanism, while 2-mediated hydrosilylation occurs via insertion.
- Mukhopadhyay, Tufan K.,Rock, Christopher L.,Hong, Mannkyu,Ashley, Daniel C.,Groy, Thomas L.,Baik, Mu-Hyun,Trovitch, Ryan J.
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p. 4901 - 4915
(2017/04/11)
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- Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst
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The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a η4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min-1 (4,950 min-1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min-1 (165 min-1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylene-bridged variant (Ph2PPrPDI)Mn; however, [(Ph2PEtPDI)Mn]2 is more easily inhibited by donor functionalities. Carbonyl and carboxylate hydrosilylation is believed to proceed through a modified Ojima mechanism following dimer dissociation.
- Mukhopadhyay, Tufan K.,Ghosh, Chandrani,Flores, Marco,Groy, Thomas L.,Trovitch, Ryan J.
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supporting information
p. 3477 - 3483
(2017/10/03)
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- Catalytic Ester Metathesis Reaction and Its Application to Transfer Hydrogenation of Esters
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We report a Ru-complex-catalyzed ester metathesis reaction where an unsymmetrical ester such as ethyl hexanoate can be transformed to a mixture of starting material, hexyl ethanoate, ethyl acetate, and hexyl hexanoate in equal proportions, as expected from a classical metathesis reaction with 0.2 mol % catalyst. A 20× excess of low boiling alcohol, such as ethanol, allows for the transfer of an acyl moiety to the sacrificial low boiling ethyl acetate product, while significantly increasing the functional group tolerance and substrate scope; yields of alcohols can reach 90%, which represents an attractive alternative to current high H2 pressure hydrogenation protocols for Ru-based ester reduction chemistry. Both reactions have not been reported previously in the field of Ru-catalyzed transformations of the ester functionality.
- Dubey, Abhishek,Khaskin, Eugene
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p. 3998 - 4002
(2016/07/06)
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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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- Improved Second Generation Iron Pincer Complexes for Effective Ester Hydrogenation
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Hydrogenation of esters to alcohols with a well-defined iron iPr2PNP pincer complex has been recently reported by us and other groups. We now introduce a novel and sterically less hindered Et2PNP congener that provides superior catalytic activity in the hydrogenation of various carboxylic acid esters and lactones compared to the known complex. Successful hydrogenation proceeds under relatively mild conditions (60°C) with lower catalyst loadings.
- Elangovan, Saravanakumar,Wendt, Bianca,Topf, Christoph,Bachmann, Stephan,Scalone, Michelangelo,Spannenberg, Anke,Jiao, Haijun,Baumann, Wolfgang,Junge, Kathrin,Beller, Matthias
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supporting information
p. 820 - 825
(2016/03/09)
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- Hydrogenation of Esters to Alcohols Catalyzed by Defined Manganese Pincer Complexes
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The first manganese-catalyzed hydrogenation of esters to alcohols has been developed. The combination of Mn(CO)5Br with [HN(CH2CH2P(Et)2)2] leads to a mixture of cationic and neutral Mn PNP pincer complexes, which enable the reduction of various ester substrates, including aromatic and aliphatic esters as well as diesters and lactones. Notably, related pincer complexes with isopropyl or cyclohexyl substituents showed very low activity.
- Elangovan, Saravanakumar,Garbe, Marcel,Jiao, Haijun,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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supporting information
p. 15364 - 15368
(2016/12/03)
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- A practical and highly efficient reductive dehalogenation of aryl halides using heterogeneous Pd/AlO(OH) nanoparticles and sodium borohydride
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The reductive dehalogenation of aryl halides was performed by using commercially available aluminium oxy-hydroxide-supported palladium (Pd/AlO(OH)) nanoparticles of about 3?nm size (0.5?wt.?% Pd) with sodium borohydride. The dehalogenated products were obtained with absolute conversion in a mixture of H2O/MeOH (v/v=1/1) under ultrasonic conditions at room temperature. All aryl halides were successfully converted to halogen-free compounds within 1.5–4?h with yields of over 95%. The one-pot catalytic method is presented as a new process for the reductive dehalogenation of halogenated compounds. This method is quite simple, highly efficient and eco-friendly, and has an exceptional recovery rate.
- Kara, Belguzar Yasemin,Yazici, Melike,Kilbas, Benan,Goksu, Haydar
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p. 5898 - 5902
(2016/09/07)
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- Towards a general ruthenium-catalyzed hydrogenation of secondary and tertiary amides to amines
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A broad range of secondary and tertiary amides has been hydrogenated to the corresponding amines under mild conditions using an in situ catalyst generated by combining [Ru(acac)3], 1,1,1-tris(diphenylphosphinomethyl)ethane (Triphos) and Yb(OTf)3. The presence of the metal triflate allows to mitigate reaction conditions compared to previous reports thus improving yields and selectivities in the desired amines. The excellent isolated yields of two scale-up experiments corroborate the feasibility of the reaction protocol. Control experiments indicate that, after the initial reduction of the amide carbonyl group, the reaction proceeds through the reductive amination of the alcohol with the amine arising from collapse of the intermediate hemiaminal.
- Cabrero-Antonino, Jose R.,Alberico, Elisabetta,Junge, Kathrin,Junge, Henrik,Beller, Matthias
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p. 3432 - 3442
(2016/05/19)
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