- Highly selective hydrogenation of CO2 into C2+ alcohols by homogeneous catalysis
-
The hydrogenation of CO2 to produce alcohols with two or more carbons (C2+ alcohols) is of great importance, but is challenging. In this work, we found that a Ru3(CO)12/Rh2(CO)4Cl2-LiI system could catalyze the reaction effectively in 1,3-dimethyl-2-imidazolidinone (DMI) under mild conditions. Methanol, ethanol, propanol, 2-methyl propanol, butanol, and 2-methyl butanol were produced in the homogeneous catalytic reaction. The C2+ alcohols could be generated at 160 °C, which is the lowest temperature reported so far for producing C2+ alcohols via CO2 hydrogenation. The selectivity for the C2+ alcohols could be as high as 96.4% at the optimized conditions, which is higher than those reported in the literature. In addition, the catalytic system could be easily recycled. The route of the reaction for forming the C2+ alcohols was discussed on the basis of control experiments.
- Qian, Qingli,Cui, Meng,He, Zhenhong,Wu, Congyi,Zhu, Qinggong,Zhang, Zhaofu,Ma, Jun,Yang, Guanying,Zhang, Jingjing,Han, Buxing
-
-
Read Online
- Highly stereoselective allylic ethylation with alkoxytitanacyclopropane reagents. Synthesis of (1R/S,7R)-1,7-dimethylnonyl propanoate, the Western corn rootworm sex attractant
-
Allylic ethylation of 2-((E)-dodec-2-en-4-yloxy)tetrahydro-2H-pyran with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide proceeds via a SN2′ pathway to afford (E)-3-methyltridec-4-ene with excellent syn-diastereoselecivity. This transformation is used as a key step in the synthesis of (1R/S,7R)-1,7-dimethylnonyl propanoate, the Western corn rootworm (Diabrotica virgifera virgifera) sex attractant.
- Isakov, Vladimir E.,Kulinkovich, Oleg G.
-
-
Read Online
- Substrate profiling and aldehyde dismutase activity of the Kvβ2 subunit of the mammalian Kv1 potassium channel
-
Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo-keto reductase (AKR) superfamily of proteins. Recent studies have shown that Kvβ2 can catalyze the reduction of aldehydes and, most significantly, that channel function is modulated when Kvβ2-bound NADPH is concomitantly oxidized. As a result, the redox chemistry of this subunit is crucial to understanding its role in K+ channel modulation. The present study has extended knowledge of the substrate profile of this subunit using a single turnover fluorimetric assay. Kvβ2 was found to catalyse the reduction of aromatic aldehyde substrates such as 2, 3 and 4-nitrobenzaldehydes, 4-hydroxybenzaldehyde, pyridine 2-aldehyde and benzaldehyde. The presence of an electron withdrawing group at the position para to the aldehyde in aromatic compounds facilitated reduction. Aliphatic aldehydes proved to be poor substrates. We devised a simple HPLC-based assay to identify Kvβ2 reaction products. Using this assay we showed, for the first time, that Kvβ2 can catalyze a slow aldehyde dismutation reaction using 4-nitrobenzaldehyde as substrate and have identified the products of this reaction. The ability of Kvβ2 to carry out both an aldehyde reduction and a dismutation reaction is discussed in the light of current thinking on the role of redox chemistry in channel modulation.
- Alka, Kumari,Ryan, Barry J.,Dolly, J. Oliver,Henehan, Gary T.M.
-
-
Read Online
- Uranyl(VI) Triflate as Catalyst for the Meerwein-Ponndorf-Verley Reaction
-
Catalytic transformation of oxygenated compounds is challenging in f-element chemistry due to the high oxophilicity of the f-block metals. We report here the first Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl substrates with uranium-based catalysts, in particular from a series of uranyl(VI) compounds where [UO2(OTf)2] (1) displays the greatest efficiency (OTf = trifluoromethanesulfonate). [UO2(OTf)2] reduces a series of aromatic and aliphatic aldehydes and ketones into their corresponding alcohols with moderate to excellent yields, using iPrOH as a solvent and a reductant. The reaction proceeds under mild conditions (80 °C) with an optimized catalytic charge of 2.3 mol % and KOiPr as a cocatalyst. The reduction of aldehydes (1-10 h) is faster than that of ketones (>15 h). NMR investigations clearly evidence the formation of hemiacetal intermediates with aldehydes, while they are not formed with ketones.
- Kobylarski, Marie,Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
-
supporting information
p. 16140 - 16148
(2021/11/01)
-
- Chromium-Catalyzed Production of Diols From Olefins
-
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
- -
-
Paragraph 0111
(2021/03/19)
-
- Carbon monoxide and hydrogen (syngas) as a C1-building block for selective catalytic methylation
-
A catalytic reaction using syngas (CO/H2) as feedstock for the selective β-methylation of alcohols was developed whereby carbon monoxide acts as a C1 source and hydrogen gas as a reducing agent. The overall transformation occurs through an intricate network of metal-catalyzed and base-mediated reactions. The molecular complex [Mn(CO)2Br[HN(C2H4PiPr2)2]]1comprising earth-abundant manganese acts as the metal component in the catalytic system enabling the generation of formaldehyde from syngas in a synthetically useful reaction. This new syngas conversion opens pathways to install methyl branches at sp3carbon centers utilizing renewable feedstocks and energy for the synthesis of biologically active compounds, fine chemicals, and advanced biofuels.
- Kaithal, Akash,H?lscher, Markus,Leitner, Walter
-
p. 976 - 982
(2021/02/06)
-
- Synthesis and mass spectra of rearrangement bio-signature metabolites of anaerobic alkane degradation via fumarate addition
-
Metabolite profiling in anaerobic alkane biodegradation plays an important role in revealing activation mechanisms. Apart from alkylsuccinates, which are considered to be the usual biomarkers via fumarate addition, the downstream metabolites of C-skeleton rearrangement can also be regarded as biomarkers. However, it is difficult to detect intermediate metabolites in both environmental samples and enrichment cultures, resulting in lacking direct evidence to prove the occurrence of fumarate addition pathway. In this work, a synthetic method of rearrangement metabolites was established. Four compounds, namely, propylmalonic acid, 2-(2-methylbutyl)malonic acid, 2-(2-methylpentyl)malonic acid and 2-(2-methyloctyl)malonic acid, were synthesized and determined by four derivatization approaches. Besides, their mass spectra were obtained. Four characteristic ions were observed at m/z 133 + 14n, 160 + 28n, 173 + 28n and [M - (45 + 14n)]+ (n = 0 and 2 for ethyl and n-butyl esters, respectively). For methyl esterification, mass spectral features were m/z 132, 145 and [M - 31]+, while for silylation, fragments were m/z 73, 147, 217, 248, 261 and [M - 15]+. These data provide basis on identification of potential rearrangement metabolites in anaerobic alkane biodegradation via fumarate addition.
- Chen, Jing,Zhou, Lei,Liu, Yi-Fan,Hou, Zhao-Wei,Li, Wei,Mbadinga, Serge Maurice,Zhou, Jing,Yang, Tao,Liu, Jin-Feng,Yang, Shi-Zhong,Wu, Xiao-Lin,Gu, Ji-Dong,Mu, Bo-Zhong
-
-
- METHOD FOR PRODUCING ALCOHOL
-
PROBLEM TO BE SOLVED: To provide a method for producing selectively alcohol from carboxylic acid under mild conditions. SOLUTION: In the presence of a catalyst with M1 and M2 as metal species supported on a support, a substrate is reduced to produce a corresponding alcohol. (M1 is Rh, Pt, Ru, Ir, or Pd; M2 is Sn, V, Mo, W, or Re; the support is ZrO2, hydroxyapatite, Nb2O5, fluoroapatite, or hydrotalcite; the substrate is the formula 1a, 1b, or 1c). SELECTED DRAWING: None COPYRIGHT: (C)2020,JPO&INPIT
- -
-
Paragraph 0101-0110
(2020/11/26)
-
- Regulating Hydrogenation Chemoselectivity of α,β-Unsaturated Aldehydes by Combination of Transfer and Catalytic Hydrogenation
-
Two hydrogenation mechanisms, transfer and catalytic hydrogenation, were combined to achieve higher regulation of hydrogenation chemoselectivity of cinnamyl aldehydes. Transfer hydrogenation with ammonia borane exclusively reduced C=O bonds to get cinnamyl alcohol, and Pt-loaded metal–organic layers efficiently hydrogenated C=C bonds to synthesize phenyl propanol with almost 100 % conversion rate. The hydrogenation could be performed under mild conditions without external high-pressure hydrogen and was applicable to various α,β-unsaturated aldehydes.
- Zhou, Yangyang,Li, Zihao,Liu, Yanbo,Huo, Jia,Chen, Chen,Li, Qiling,Niu, Songyang,Wang, Shuangyin
-
p. 1746 - 1750
(2020/02/25)
-
- Upgrading 1-butanol to unsaturated, carbonyl and aromatic compounds: A new synthesis approach to produce important organic building blocks
-
Unsaturated, carbonyl and aromatic products were obtained by reacting 1-butanol or a 1-butanol:methanol mixture with a copper mixed metal oxide catalyst in a fixed bed reactor. The selectivities observed, mostly for the unsaturated and carbonyl products, can represent a new alternative and greener pathway for the production of fine-chemicals and organic building blocks.
- Boscolo, Mauricio,Metzker, Gustavo,Mora Vargas, Jorge,Orduna Ortega, Julieth,Tofaneli Morelato, Luiz Henrique
-
supporting information
p. 2365 - 2369
(2020/05/13)
-
- Manganese(I)-Catalyzed β-Methylation of Alcohols Using Methanol as C1 Source
-
Highly selective β-methylation of alcohols was achieved using an earth-abundant first row transition metal in the air stable molecular manganese complex [Mn(CO)2Br[HN(C2H4PiPr2)2]] 1 ([HN(C2H4PiPr2)2]=MACHO-iPr). The reaction requires only low loadings of 1 (0.5 mol %), methanolate as base and MeOH as methylation reagent as well as solvent. Various alcohols were β-methylated with very good selectivity (>99 %) and excellent yield (up to 94 %). Biomass derived aliphatic alcohols and diols were also selectively methylated on the β-position, opening a pathway to “biohybrid” molecules constructed entirely from non-fossil carbon. Mechanistic studies indicate that the reaction proceeds through a borrowing hydrogen pathway involving metal–ligand cooperation at the Mn-pincer complex. This transformation provides a convenient, economical, and environmentally benign pathway for the selective C?C bond formation with potential applications for the preparation of advanced biofuels, fine chemicals, and biologically active molecules.
- Kaithal, Akash,van Bonn, Pit,H?lscher, Markus,Leitner, Walter
-
supporting information
p. 215 - 220
(2019/12/03)
-
- Ruthenium(II)-Catalyzed β-Methylation of Alcohols using Methanol as C1 Source
-
Selective introduction of methyl branches into the carbon chains of alcohols can be achieved with low loadings of ruthenium precatalyst [RuH(CO)(BH4)(HN(C2H4PPh2)2)] (Ru-MACHO-BH) using methanol both as methylating reagent and as reaction medium. A wide range of structurally divers alcohols was β-methylated with excellent selectivity (>99 %) in fair to high yields (up to 94 %) under standard conditions, and turnover numbers up to 18,000 could be established. The overall reaction rate of the complex catalytic network appears to be governed by interconnection of the individual subcycles through availability of the reactive intermediates. The synthetic procedure opens pathways to important structural motifs following the Green Chemistry principles.
- Kaithal, Akash,Schmitz, Marc,H?lscher, Markus,Leitner, Walter
-
p. 5287 - 5291
(2019/05/28)
-
- 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
-
p. 785 - 789
(2018/02/14)
-
- Encapsulation of Crabtree's Catalyst in Sulfonated MIL-101(Cr): Enhancement of Stability and Selectivity between Competing Reaction Pathways by the MOF Chemical Microenvironment
-
Crabtree's catalyst was encapsulated inside the pores of the sulfonated MIL-101(Cr) metal–organic framework (MOF) by cation exchange. This hybrid catalyst is active for the heterogeneous hydrogenation of non-functionalized alkenes either in solution or in the gas phase. Moreover, encapsulation inside a well-defined hydrophilic microenvironment enhances catalyst stability and selectivity to hydrogenation over isomerization for substrates bearing ligating functionalities. Accordingly, the encapsulated catalyst significantly outperforms its homogeneous counterpart in the hydrogenation of olefinic alcohols in terms of overall conversion and selectivity, with the chemical microenvironment of the MOF host favouring one out of two competing reaction pathways.
- Grigoropoulos, Alexios,McKay, Alasdair I.,Katsoulidis, Alexandros P.,Davies, Robert P.,Haynes, Anthony,Brammer, Lee,Xiao, Jianliang,Weller, Andrew S.,Rosseinsky, Matthew J.
-
supporting information
p. 4532 - 4537
(2018/03/26)
-
- Iridium Clusters Encapsulated in Carbon Nanospheres as Nanocatalysts for Methylation of (Bio)Alcohols
-
C?H methylation is an attractive chemical transformation for C?C bonds construction in organic chemistry, yet efficient methylation of readily available (bio)alcohols in water using methanol as sustainable C1 feedstock is limited. Herein, iridium nanocatalysts encapsulated in yolk–shell-structured mesoporous carbon nanospheres (Ir@YSMCNs) were synthesized for this transformation. Monodispersed Ir clusters (ca. 1.0 nm) were encapsulated in situ and spatially isolated within YSMCNs by a silica-assisted sol–gel emulsion strategy. A selection of (bio)alcohols (19 examples) was selectively methylated in aqueous phase with good-to-high yields over the developed Ir@YSMCNs. The improved catalytic efficiencies in terms of activity and selectivity together with the good stability and recyclability were contributable to the ultrasmall Ir clusters with oxidation chemical state as a consequence of the confinement effect of YSMCNs with interconnected nanostructures.
- Liu, Qiang,Xu, Guoqiang,Wang, Zhendong,Liu, Xiaoran,Wang, Xicheng,Dong, Linlin,Mu, Xindong,Liu, Huizhou
-
p. 4748 - 4755
(2017/12/15)
-
- Photocatalytic Regeneration of Nicotinamide Cofactors by Quantum Dot-Enzyme Biohybrid Complexes
-
We report the characterization of biohybrid complexes of CdSe quantum dots and ferredoxin NADP+-reductase for photocatalytic regeneration of NADPH. Illumination with visible light led to reduction of NADP+ to NADPH, with an apparent kcat of 1400 h-1. Regeneration of NADPH was coupled to reduction of aldehydes to alcohols catalyzed by a NADPH-dependent alcohol dehydrogenase, with each NADPH molecule recycled an average of 7.5 times. The quantum yield both of NADPH and alcohol production were 5-6% for both products. Light-driven NADPH regeneration was also demonstrated in a multienzyme system, showing the capacity of QD-FNR complexes to drive continuous NADPH-dependent transformations.
- Brown, Katherine A.,Wilker, Molly B.,Boehm, Marko,Hamby, Hayden,Dukovic, Gordana,King, Paul W.
-
p. 2201 - 2204
(2016/04/26)
-
- A sustainable process for the production of 2-methyl-1,4-butanediol by hydrogenation of biomass-derived itaconic acid
-
Pd-ReOx/C catalysts with different Re contents were prepared and employed to catalyze the aqueous hydrogenation of itaconic acid in this study. The Pd-ReOx/C catalysts were characterized by XRD, TEM, BET, NH3-TPD and H2-TPR. Results showed that the addition of ReOx species in supported Pd catalysts promoted the direct conversion of itaconic acid to 2-methyl-1,4-butanediol. The promoting effect was ascribed to the interaction between Pd and ReOx species, as has been proved by the characterizations. A 2-methyl-1,4-butanediol yield of above 80% could be obtained over Pd-3ReOx/C under the reaction condition of 180 °C, 4 MPa H2.
- Liu, Xiaoran,Wang, Xicheng,Liu, Qiang,Xu, Guoqiang,Li, Xuemin,Mu, Xindong
-
-
- METHOD FOR PRODUCING UNSATURATED ALCOHOL
-
PROBLEM TO BE SOLVED: To provide a method for producing an unsaturated alcohol that uses an unsaturated carbonyl compound as a raw material and can produce an unsaturated alcohol in which only the carbonyl bond of the unsaturated carbonyl compound is selectively reduced with excellent reaction rate, high selectivity and high yield. SOLUTION: The process for producing an unsaturated alcohol includes a step of allowing the reductive reaction of a 3C or more unsaturated carbonyl compound having one or more carbon-carbon unsaturated bonds in the molecule with hydrogen to proceed in the presence of a catalyst comprising at least one kind of metal selected from the group consisting of cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, silver, osmium, iridium and platinum and at least one kind of metal selected from the group consisting of vanadium, chromium, manganese, iron, molybdenum, tungsten and rhenium to produce a corresponding unsaturated alcohol. COPYRIGHT: (C)2015,JPOandINPIT
- -
-
Paragraph 0074-0076
(2017/01/02)
-
- Expanding ester biosynthesis in Escherichia coli
-
To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l -1). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.
- Rodriguez, Gabriel M,Tashiro, Yohei,Atsumi, Shota
-
p. 259 - 265
(2014/04/03)
-
- Hydrogenation of esters catalyzed by ruthenium PN3-Pincer complexes containing an aminophosphine arm
-
Hydrogenation of esters under mild conditions was achieved using air-stable ruthenium PN3-pincer complexes containing an aminophosphine arm. High efficiency was achieved even in the presence of water. DFT studies suggest a bimolecular proton shuttle mechanism which allows H2 to be activated by the relatively stable catalyst with a reasonably low transition state barrier.
- Chen, Tao,Li, Huaifeng,Qu, Shuanglin,Zheng, Bin,He, Lipeng,Lai, Zhiping,Wang, Zhi-Xiang,Huang, Kuo-Wei
-
p. 4152 - 4155
(2014/09/30)
-
- Rapid synthesis of unsaturated alcohols under mild conditions by highly selective hydrogenation
-
Ir-ReOx/SiO2 acted as a highly active and selective heterogeneous catalyst for the hydrogenation of unsaturated aldehydes to unsaturated alcohols in water at low H2 pressure (0.8 MPa) and low temperature (303 K). The catalysis is derived from the synergy between Ir metal and ReOx.
- Tamura, Masazumi,Tokonami, Kensuke,Nakagawa, Yoshinao,Tomishige, Keiichi
-
supporting information
p. 7034 - 7036
(2013/09/02)
-
- From olefins to alcohols: Efficient and regioselective ruthenium-catalyzed domino hydroformylation/reduction sequence
-
Exploring the alternatives: Ruthenium imidazoyl phosphine complexes catalyze the domino hydroformylation/reduction of alkenes to alcohols in good yields and with good selectivities (see scheme). Linear aliphatic alcohols are synthesized under reaction conditions typically used in industrial hydroformylations. Copyright
- Fleischer, Ivana,Dyballa, Katrin Marie,Jennerjahn, Reiko,Jackstell, Ralf,Franke, Robert,Spannenberg, Anke,Beller, Matthias
-
supporting information
p. 2949 - 2953
(2013/04/10)
-
- MCl2(ampy)(dppf) (M = Ru, Os): Multitasking catalysts for carbonyl compound/alcohol interconversion reactions
-
The easily accessible complexes [MCl2(dppf)(ampy)] (M = Ru (cis-1), Os (trans-2); dppf = 1,1′-bis(diphenylphosphino)ferrocene; ampy = 2-aminomethylpyridine) in the presence of base (NaOiPr, KOtBu) are efficient catalysts for several reactions involving carbonyl compounds and alcohols. The derivatives 1 and 2 catalyze the selective transfer hydrogenation of aldehydes and ketones to alcohols with 2-propanol using 0.1-0.005 mol % of catalyst at 82 °C with TOF values up to 3.0 × 105 h-1. These compounds (0.1-0.02 mol %) promote the hydrogenation of aldehydes and ketones in EtOH or a MeOH/EtOH mixture at 30-90 °C (5 atm of H2) and the acceptorless dehydrogenation of alcohols to ketones in tBuOH at 130-145 °C (0.4 mol %). Complexes 1 and 2 (0.5 mol %) catalyze the racemization of chiral alcohols at 70 °C in 2-propanol and the isomerization of allylic alcohols to ketones in tBuOH at 70-120 °C (1 mol %). In addition, 1 and 2 (0.5 mol %) promote the α alkylation of α-tetralone with primary alcohols (EtOH, nPrOH, and nBuOH) at 120 °C in a tBuOH/toluene mixture (1/2 v/v). Complex 2 is easily obtained in 93% yield from [OsCl2(PPh3) 3], dppf, and ampy in toluene.
- Putignano, Elisabetta,Bossi, Gianluca,Rigo, Pierluigi,Baratta, Walter
-
experimental part
p. 1133 - 1142
(2012/04/04)
-
- Discrete iron complexes for the selective catalytic reduction of aromatic, aliphatic, and α,β-unsaturated aldehydes under water-gas shift conditions
-
Iron-catalyzed reductions: Selective iron-catalyzed reduction of aldehydes with hydrogen generated in situ by the water-gas shift reaction is presented (see scheme). The generality and selectivity of this mild procedure are demonstrated by the efficient reduction of various aromatic, aliphatic and α,β-unsaturated aldehydes.
- Tlili, Anis,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
-
p. 15935 - 15939
(2013/02/21)
-
- Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
-
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
- Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
-
supporting information
p. 10609 - 10616
(2012/11/07)
-
- METHOD FOR SYNTHESIS OF CHEMICAL INDUSTRIAL RAW MATERIAL OR FUEL COMPOSITION
-
The present invention is to provide a novel method for manufacturing various organic compounds from 2 or more kinds of alcohol, or 1 kind of alcohol having 3 or more carbon atoms. It is a method for synthesizing 1 kind of, or 2 or more kinds of organic compounds comprising allowing 2 or more kinds of alcohol or 1 kind of alcohol having 3 or more carbon atoms to contact hydroxyapatite (except those supporting metal catalysts or metal ion catalysts acting on alcohol).
- -
-
Page/Page column 15
(2009/08/14)
-
- METHODS FOR THE ECONOMICAL PRODUCTION OF BIOFUEL FROM BIOMASS
-
Methods for producing a biofuel are provided. Also provided are biocatalysts that convert a feedstock to a biofuel.
- -
-
-
- Photochemistry of thiophene-S-oxide derivatives
-
Photolysis of substituted thiophene-S-oxides in solution results in the formation of either the corresponding thiophene or furan, in addition to uncharacterized materials. No good rationalization is available for the choice of which pathway may predominat
- Heying, Melanie J.,Nag, Mrinmoy,Jenks, William S.
-
body text
p. 915 - 924
(2009/10/26)
-
- Fast and chemoselective transfer hydrogenation of aldehydes catalyzed by a terdentate CNN ruthenium complex [RuCl(CNN)(dppb)]
-
Aromatic, aliphatic and α,β-unsaturated aldehydes are quickly, quantitatively and chemoselectively reduced to primary alcohols with 2-propanol using 0.05-0.01 mol% of the terdentate CNN ruthenium complex RuCl(CNN)(dppb) (1) [HCNN = 6-(4′-methylphenyl)-2-pyridylmethylamine; dppb = Ph 2P(CH2)4PPh2] in the presence of potassium carbonate (K2CO3; 1-10 mol%) as a weak base, affording TOF values up to 5.0 × 105 h-1.
- Baratta, Walter,Siega, Katia,Rigo, Pierluigi
-
p. 1633 - 1636
(2008/02/11)
-
- Method for producing amines by homogeneously catalyzed reductive amination of carbonyl compounds
-
The invention relates to the preparation of chiral or achiral amines by reaction of aldehydes or ketones with ammonia or primary or secondary amines in the presence of hydrogen and in the presence of homogeneous metal catalysts under mild conditions. Metal catalysts which can be used are complexes of late transition metals with chiral or achiral phosphorus-containing ligands.
- -
-
Page/Page column 12; 17-18
(2010/02/11)
-
- Process for the preparation of 3-methyltetrahydrofuran
-
Disclosed is a process for the preparation of 3-methyltetrahydrofuran (MeTHF) from 3-(hydroxymethyl)tetrahydrofuran (HOMeTHF) by contacting HOMeTHF with hydrogen in the presence of an acidic, supported catalyst comprising a Group VIII metal.
- -
-
Page/Page column 6-7
(2008/06/13)
-
- Stereocontrol of 1,5-related stereocentres using an intermediate silyl group-the diastereoselectivity of nucleophilic attack on a double bond adjacent to a stereogenic carrying a silyl group
-
R-5-Methylcyclohex-2-enone 1 reacts successively with the phenyldimethylsilylzincate reagent and acetaldehyde to give with regiocontrol the aldols 7, dehydration of which creates the E-exocyclic double bond of the α-β-unsaturated ketone 2. Conjugate addition of the ethylcuprate reagent to this compound takes place with high (96 : 4) selectivity in favour of the R stereoisomer 12, hydrolysis of which gives (2R,3R,5S,2′ R)-2-(but-2′-yl)-3-dimethyl(phenyl)silyl-5-methylcyclohexanone 3. The oxime acetate of this ketone undergoes fragmentation in the presence of trimethylsilyl trifluoromethanesulfonate to give 3R,7R,5E-3,7-dimethylnon-5-enonitrile 4, in which an open-chain 1,5-stereo-chemical relationship is set up with a high level of stereocontrol. A similar sequence adding 4-methylpentylcuprate to the enone 2, and fragmentation gives 3R,7R,5E-3,7,11-trimethyldodec-5-enonitrile 20. Reduction and hydrogenation of this nitrile gives 3R,7R-3,7,11 -trimethyldodecanal 22, which can be converted into phytol 25. The ketoaldehyde 29 reacts with samarium iodide to give only the alcohol 30, in which the radical anion has attacked from the top surface, just like the cuprate reagents in their reactions with the ketone 2.
- Fleming, Ian,Maiti, Pranab,Ramarao, Chandrashekar
-
p. 3989 - 4004
(2007/10/03)
-
- Method for preparing a benzylic-type ether
-
The invention concerns a method for preparing a benzylic-type ether from an aromatic compound. The inventive method for preparing a benzylic-type ether from an aromatic compound is characterised in that it consists in: in a first step, acylating an aromatic compound by reacting said aromatic compound with an acylating agent, in the presence of an efficient amount of zeolite or a Friedel-Crafts catalyst leading to a ketonic compound; in a second step, reducing the carbonyl group into carbinol leading to a benzylic alcohol; in a third step, etherifying the hydroxyl group, by reacting the benzylic alcohol with another alcohol, in the presence of an efficient amount of zeolite.
- -
-
-
- A Scrutiny on the Reductive Amination of Carbonyl Compounds Catalyzed by Homogeneous Rh(I) Diphosphane Complexes
-
The reductive amination of a series of aldehydes with secondary amines and H2 in the presence of a homogeneous Rh-diphosphane catalyst was studied in order to establish a general mechanism of this reaction and to identify conditions for the improvement of the amine/alcohol ratio in the product. Several possible intermediates as constituents of changing equilibria like half-aminals, N,O-acetals and aminals were observed in the reaction mixture by means of 1H NMR spectroscopy. In individual trials, these compounds could be successfully hydrogenated under the conditions applied for reductive amination (50 bar H2 pressure, MeOH). Some evidence is accumulated that half-aminals and N,O-acetals might be key intermediates of the reductive amination. Moreover, it was found that the formation of the undesired product alcohol is likely based on the reduction of the starting carbonyl compound. However, due to numerous equilibria consisting of several intermediates, general conclusions are hard to be drawn. Proof will be given that, in several cases, the efficiency of the reductive amination of aliphatic aldehydes can be significantly improved by prehydrogenation of the cationic [Rh(dppb)(COD)]+ complex.
- Tararov, Vitali I.,Kadyrov, Renat,Riermeier, Thomas H.,Boerner, Armin
-
p. 200 - 208
(2007/10/03)
-
- Hydroboration. 97. Synthesis of new exceptional chloroborane-Lewis base adducts for hydroboration. Dioxane-monochloroborane as a superior reagent for the selective hydroboration of terminal alkenes
-
Several less volatile oxygen-containing Lewis bases, such as tert-butyl methyl ether, dioxane, anisole, ethyl acetate, β-chloroethyl ether, and monoglyme, were examined as prospective mono- and dichloroborane carriers. Dioxane, ethyl acetate, and β-chloroethyl ether form relatively stable boron trichloride adducts, but the boron trichloride adduct of monoglyme is not very stable and must be used immediately. On the other hand, tert-butyl methyl ether and anisole fail to form stable boron trichloride adducts and the corresponding ether-cleaved products are obtained. Among the selected oxygen-containing Lewis bases, only dioxane forms stable and reactive mono- and dichloroborane adducts. Monoglyme and β-chloroethyl ether give stable dichloroborane adducts requiring excess of diborane. Convenient methods for the preparation of mono- and dichloroborane adducts of dioxane from dioxane-BCl3 and NaBH4 in the presence of catalytic amounts of tri- or tetraglyme were developed. The dioxane-monochloroborane adduct hydroborates representative olefins cleanly and rapidly. The corresponding alcohols were obtained in quantitative yields after oxidation. Also, the hydroboration of several terminal olefins with dioxane-monochloroborane were highly regioselective and the primary alcohols were obtained almost exclusively (>99.5%), after oxidation. Accordingly, dioxane-monochloroborane should serve as a reagent of choice for such hydroborations. The dioxane-dichloroborane adduct showed remarkable selectivity toward 2-substituted terminal olefins, such as 2-methyl-1-butene and β-pinene, when compared to simple terminal and hindered olefins, giving a unique tool for selective hydroborations. Dichloroborane adducts of monoglyme and β-chloroethyl ether also showed high reactivity, even at room temperature, toward simple unhindered olefins. However, hydroboration of hindered olefins is slow and requires either higher temperatures or the addition of 1 equiv of boron trichloride to liberate free dichloroborane, as in the case of the previously known dichloroborane adducts of methyl sulfide and diethyl ether.
- Kanth,Brown
-
p. 5359 - 5365
(2007/10/03)
-
- Unusual rapid hydroboration of alkenes using diborane in chlorohydrocarbon solvents
-
Diborane dissolves in chlorohydrocarbon solvents, such as dichloromethane, 1,2-dichloroethane and 1,1,2,2-tetrachloroethane to form ~0.5 M solutions of B2H6. In these solutions, diborane is in equilibrium with solvent-BH3 adducts (8-15%) and these solutions hydroborate representative olefins almost instantaneously, even at -16°C. The alcohol products can be obtained by standard oxidation of these organoboranes. (C) 2000 Elsevier Science Ltd.
- Kanth,Brown
-
p. 9361 - 9364
(2007/10/03)
-
- On the reductive amination of aldehydes and ketones catalyzed by homogeneous Rh(I) complexes
-
The homogeneously catalyzed reductive amination of aldehydes and ketones under smooth conditions is reported, showing for the first time, that Rh(I) catalysts based on chelating diphosphines and diphosphinites can be advantageously employed for this reaction, even for the production of chiral amino acid derivatives.
- Tararov,Kadyrov,Riermeier,Borner
-
p. 1867 - 1868
(2007/10/03)
-
- Dioxane-monochloroborane: A new and highly reactive hydroborating reagent with exceptional properties
-
(equation presented) Dioxane-monochloroborane was prepared by the reaction of dioxane and dioxane-BCl3 with diborane or NaBH4 in 98% purity. The adduct thus obtained is a liquid, 6.2 M in BH2Cl, stable indefinitely at either 0 or 25°C. The adduct hydroborates simple unhindered olefins to the corresponding dialkylchloroboranes within 0.5 h, while moderately hindered olefins take 1-4 h at room temperature. Hindered tetrasubstituted olefins rapidly hydroborate to the monoalkylchloroborane stage with further hydroboration slow. Regioselectivity studies of representative olefins reveal that this new reagent possesses selectivities similar to those from the monochloroborane-diethyl ether adduct. Consequently, dioxane-monochloroborane can readily substitute for the older hydroborating agents, BH3:THF and BH3:DMS.
- Kanth, Josyula V. B.,Brown, Herbert C.
-
p. 315 - 317
(2008/02/11)
-
- The role of functionalized phosphines in the hydrogenation of carboxylic acids in the presence of phosphine substituted hydrido ruthenium complexes
-
Hydrido ruthenium carbonyl complexes substituted by functionalized phosphines such as H4Ru4(CO)8[P(CH2OCOR) 3]4 have been synthesized and tested as catalysts in the hydrogenation of carboxylic acids. These complexes are more active than those reported previously, containing trialkyl- or triarylphosphines. On the basis of their behavior, their different activity has been explained in terms of an involvement of the phosphine ligand in the catalytic cycle. The ester group present in the phosphine P(CH2OCOR)3 is hydrogenated to produce an alcohol (RCH2OH) and a P(CH2OH) group which, in turn, reacts with the free acid present in solution to restore the P(CH2OCOR) group. This hypothesis has been confirmed by the reactivity of the possible intermediate H4Ru4(CO)8[P(CH2OH) 3]4 with acetic acid. Another support to this statement is the almost equal catalytic activity, displayed by H4Ru4(CO)8[P(CH2OCOR) 3]4 complexes, whatever the R group present, in the phosphine ligand, in the hydrogenation of carboxylic acids. These complexes, on the other hand, are less active than the corresponding tributylphosphine substituted ones in the hydrogenation of alkenes and ketones. Finally when the phosphine ligand is P(CH2CH2COOCH3)3 the ester group is not reduced and consequently the catalytic activity of this complex in the hydrogenation of carboxylic acids is very low.
- Salvini, Antonella,Frediani, Piero,Bianchi, Mario,Piacenti, Franco,Pistolesi, Leonardo,Rosi, Luca
-
p. 218 - 228
(2007/10/03)
-
- Chiral organometallic compounds
-
A chiral, organometallic compound which, at a molecular level, has no C2 symmetry and comprises a carbon to carbon bond joining a chiral carbon atom to a carbon atom of a cyclopentadiene ring that is non-symmetrically substituted. Examples of such compounds include compounds of formula (I): STR1 wherein X1 and X2 are, independently, groups which are removable during a chemical reaction; M is titanium, zirconium or hafnium; and R1-8,11 are as specified in the description.
- -
-
-
- Photodeoxygenation of dibenzothiophene sulfoxide: Evidence for a unimolecular S-O cleavage mechanism
-
Photolysis of dibenzothiophene sulfoxide results in the formation of dibenzothiophene and oxidized solvent. Though quantum yields are low, chemical yields of the sulfide are quite high. Yields of the oxidized solvents can also be high. Typical products are phenol from benzene, cyclohexanol, and cyclohexene from cyclohexane and 2-cyclohexenol and epoxycyclohexane from cyclohexene. A number of experiments designed to elucidate the mechanism of the hydroxylation were carried out, including measurements of quantum yields as a function of concentration, solvent, quenchers, and excitation wavelength. These data are inconsistent with a mechanism involving a sulfoxide dimer, which also does not properly account for the solvent oxidations. It is suggested hbat the active oxidizing agent may be atomic oxygen O(3P) or a closely related noncovalent complex, based on the nature of the oxidation chemistry, comparison to known rate constants for O(3P) reactivity, and the quantum yield data.
- Gregory, Daniel D.,Wan, Zehong,Jenks, William S.
-
-
- HYDROFORMYLATION OF n-BUTENES AND BUTANE-BUTENE FRACTION USING Co2(CO)8 AS A CATALYST PRECURSOR
-
The feasibility has been examined of producing aldehydes C4H9CHO and alcohols C4H9CH2OH from the butane-butene fraction and synthesis gas CO+H2, using Co2(CO)8 as a catalyst precursor.The rate and selectivity of the reaction are influenced by the olefin and cobalt concentrations.
- Vigranenko, Yu. T.,Gavrilova, V. M.,Gvozdovskii, G. N.,Rybakov, V. A.,Kuz'mina, G. V.
-
p. 1153 - 1155
(2007/10/02)
-
- Homologation of representative boronic esters using in situ generated (halomethyl)lithiums: A comparative study
-
A comparative study of the homologation of representative boronic esters with in situ generated LiCH2X (X = Cl; Br; I) is presented wherein the reactivity differences arising out of the steric and electronic effects of the migrating groups, and the nature of the ester groups are determined and discussed.
- Soundararajan, Raman,Li, Guisheng,Brown, Herbert C.
-
p. 8957 - 8960
(2007/10/02)
-
- Catalytic Enantioselective Hydrosilylation of Aromatic Ketones Using Rhodium Complexes of TADDOL-Derived Cyclic Phosphonites and Phosphites
-
Cyclic phosphonites and phosphites 2-4 are readily available from Cl2PR and (R,R)- or (S,S)-α,α,α',α'-tetraaryl-1,3-dioxolane-4,5-dimethanols (=TADDOLs 1, which, in turn, are only two steps away from tartrate); the X-ray crystal structure of one representative, the phenyl phosphonite 2b, was determined.Five previously described and six new ones of the chiral P derivatives were tested as ligands for Rh1- and Pd0-catalyzed reactions such as hydrocarbonylations, hydroborations, and hydrosilylations of C=C bonds; while the resulting catalysts were highly active and regioselective, they did not lead to useful enantiomer enrichment in the products (Scheme 1).In contrast, hydrosilylation of phenyl and 2-naphthyl methyl or ethyl ketone by Ph2SiH2 (1.2 equiv.) gave, after desilylation, the corresponding secondary alcohols of (R)-configuration with up to 87percent ee in the presence of 0.1 equiv. of the penta(2-naphthyl)-substituted phosphonite 3d and 0.02 mol-equiv. of Rh (Table 1 ).
- Sakaki, Jun-ichi,Schweizer, W. Bernd,Seebach, Dieter
-
p. 2654 - 2665
(2007/10/02)
-
- Boron Trifluoride Promoted Aldol Reaction of Silyl Ketene Acetals with the Intermediate Generated by the DIBALH Reduction of Carboxylic Acid Esters
-
The intermediate generated by the DIBALH reduction of carboxylic acid esters undergoes a boron trifluoride promoted aldol reaction with silyl ketene acetals to afford the corresponding β-hydroxy carboxylic acid esters in good yield.
- Kiyooka, Syun-ichi,Shirouchi, Masashi
-
-
- A Convenient One-Pot Method for the Hydroxymethylation of Grignard Reagents
-
Grignard reagents and alkynyllithiums can be hydroxymethylated in a two-step one-pot reaction by reaction of a Grignard reagent with 1-chloro-2-(chloromethoxy)ethane (1), followed by treatment with sodium-potassium alloy and aqueous workup.The reaction was found to work for primary, secondary, tertiary, benzylic, allylic and aryl Grignard reagents in yields ranging from 57 - 95 percent.
- Ogle, C. A.,Wilson, T. E.,Stowe, J. A.
-
p. 495 - 496
(2007/10/02)
-
- TOTAL SYNTHESIS OF (-)-BETAENONE C
-
Stereoselctive synthesis of (-)-betaenone C through intramolecular Diels-Alder reaction has made possible to provide pertinent intermediates for the biosynthetic study of betaenones.
- Ichihara, Akitami,Miki, Shokyo,Kawagishi, Hirokazu,Sakamura, Sadao
-
p. 4551 - 4554
(2007/10/02)
-