100-51-6Relevant articles and documents
Intracrystalline reactivity of layered double hydroxides: Carboxylate alkylations in dry media
Garcia-Ponce, Angel Luis,Prevot, Vanessa,Casal, Blanca,Ruiz-Hitzky, Eduardo
, p. 119 - 121 (2000)
This work concerns the reactivity in dry media conditions, i.e. without solvents, of layered double hydroxide (LDH) solids, containing carboxylate ions in their structure, towards alkyl and benzyl halides. Reaction occurs giving the corresponding esters, with excellent yield and selectivity, and preserving the lamellar arrangement of the pristine solids. The reactions were activated by conventional thermal treatment (100 °C) or by microwave (MW) irradiation.
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Gaylord,Kay
, p. 1574 (1958)
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REDUCTIVE COUPLING OF AROMATIC ALDEHYDES BY OCTACARBONYL DIFERRATE
Ito, Keiji,Nakanishi, Saburo,Otsuji, Yoshio
, p. 1141 - 1144 (1980)
The reaction of aromatic aldehydes with Fe(CO)5 or Fe3(CO)12 in pyridine gives the corresponding 1,2-diaryl-1,2-ethanediols as major products in good yields.A reactive species of this reaction is octacarbonyl diferrate (2-).
Manganese Catalyzed Hydrogenation of Organic Carbonates to Methanol and Alcohols
Kumar, Amit,Janes, Trevor,Espinosa-Jalapa, Noel Angel,Milstein, David
, p. 12076 - 12080 (2018)
The first example of a homogeneous catalyst based on an earth-abundant metal for the hydrogenation of organic carbonates to methanol and alcohols is reported. Based on the mechanistic investigation, which indicates metal-ligand cooperation between the manganese center and the N?H group of the pincer ligand, we propose that the hydrogenation of organic carbonates to methanol occurs via formate and aldehyde intermediates. The reaction offers an indirect route for the conversion of CO2 to methanol, which coupled with the use of an earth abundant catalyst, makes the overall process environmentally benign and sustainable.
Iron-catalyzed hydrosilylation of esters
Bezier, David,Venkanna, Gopaladasu T.,Castro, Luis C. Misal,Zheng, Jianxia,Roisnel, Thierry,Sortais, Jean-Baptiste,Darcel, Christophe
, p. 1879 - 1884 (2012)
The first hydrosilylation of esters catalyzed by a well defined iron complex has been developed. Esters are converted to the corresponding alcohols at 100 °C, under solvent-free conditions and visible light activation. Copyright
A Pd@Zeolite Catalyst for Nitroarene Hydrogenation with High Product Selectivity by Sterically Controlled Adsorption in the Zeolite Micropores
Zhang, Jian,Wang, Liang,Shao, Yi,Wang, Yanqin,Gates, Bruce C.,Xiao, Feng-Shou
, p. 9747 - 9751 (2017)
The adsorption of molecules on metal nanoparticles can be sterically controlled through the use of zeolite crystals, which enhances the product selectivity in hydrogenations of reactants with more than one reducible group. Key to this success was the fixation of Pd nanoparticles inside Beta zeolite crystals to form a defined structure (Pd@Beta). In the hydrogenation of substituted nitroarenes with multiple reducible groups as a model reaction, the Pd@Beta catalyst exhibited superior selectivity for hydrogenation of the nitro group, outperforming both conventional Pd nanoparticles supported on zeolite crystals and a commercial Pd/C catalyst. The extraordinary selectivity of Pd@Beta was attributed to the sterically selective adsorption of the nitroarenes on the Pd nanoparticles controlled by the zeolite micropores, as elucidated by competitive adsorption and adsorbate displacement tests. Importantly, this strategy is general and was extended to the synthesis of selective Pt and Ru catalysts by fixation inside Beta and mordenite zeolites.
Pt/ZrO2: An efficient catalyst for aerobic oxidation of toluene in aqueous solution
Mohammad, Sadiq,Mohammad, Ilyas
, p. 2216 - 2220 (2010)
The heterogeneous oxidation of toluene in aqueous medium has been investigated. Artificially contaminated water with aromatic compound (toluene) was exposed to a simple platinized zirconia (1% Pt/ZrO2) catalyst in the presence of molecular oxyg
Organometallic chemistry sans organometallic reagents: Modulated electron-transfer reactions of sub valent early transition metal salts
Eisch, John J.,Shi, Xian,Alila, Joseph R.,Thiele, Sven
, p. 1175 - 1187 (1997)
The potential of low-valent, early transition-metal reagents as selective reductants in organic chemistry has been foreshadowed by intensive research on the ill-defined and heterogeneous subvalent titanium intermediates generated in the McMurry reaction and its numerous variants. As part of a long-term research effort to develop soluble, well-defined transition-metal reductants of modulated and selective activity toward organic substrates, the THF-soluble reductant, titanium dichloride, has been thoroughly examined, as well as the analogous ZrCl2 and HfCl2 reagents, all of which are readily obtainable by the alkylative reduction of the Group 4 tetrachloride by butyllithium in THF. Noteworthy is that such interactions of MCl4, with butyllithium in hydrocarbon media lead, in contrast, to M(III) or M(IV) halide hydrides. Analogous alkylative reductions in THF applied to VCl4, CrCl3, and MoCl5 have yielded reducing agents similar to those obtained from MCl4 but gradated in their reactivity. Such reductants have proved capable of coupling carbonyl derivatives, benzylic halides, acetylenes and certain olefins in a manner consistent with an oxidative addition involving a two-electron transfer (TET). Such a reaction pathway is consistent with the observed stereochemistry for pinacol formation from ketones and for the reductive dimerization of alkynes. In contrast to the reaction of CrCl3 with two equivalents of butyllithium, which leads to a CrCl intermediate, the interaction of CrCl3 in THF with four equivalents of butyllithium at -78°C yields a reagent of the empirical formulation, LiCrH4 · 2 LiCl · 2 THF, as supported by elemental and gasometric analysis of its protolysis. This hydridic reductant cleaves a wide gamut of o carbon-heteroatom bonds (C-X, C-O, C-S and C-N), towards which the CrCl reductant is unreactive. The type of cleavage and/or coupled products resulting from the action of "LiCrH4" on these substrates is best understood as arising from single-electron transfer (SET). In light of the aforementioned findings, the gradated reducing action noted among TiCl2, ZrCl2, HfCl2 and CrCl, as well as the contrasting reducing behavior between CrCl and LiCrH4, there is no doubt that future research with early transition metals will continue to yield novel reductants of modulated and site-selective reactivity. VCH Verlagsgesellschaft mbH,.
Tailor-Made Ruthenium-Triphos Catalysts for the Selective Homogeneous Hydrogenation of Lactams
Meuresch, Markus,Westhues, Stefan,Leitner, Walter,Klankermayer, Jürgen
, p. 1392 - 1395 (2016)
The development of a tailored tridentate ligand enabled the synthesis of a molecular ruthenium-triphos catalyst, eliminating dimerization as the major deactivation pathway. The novel catalyst design showed strongly increased performance and facilitated the hydrogenation of highly challenging lactam substrates with unprecedented activity and selectivity. Bulky catalysts: A tailored sterically demanding tridentate ligand enabled the synthesis of a novel molecular ruthenium-triphos catalyst, which eliminates dimerization as the major deactivation pathway. The novel catalyst design showed increased performance and facilitated the hydrogenation of highly challenging lactam substrates with unprecedented activity and selectivity.
Highly efficient tetradentate ruthenium catalyst for ester reduction: Especially for hydrogenation of fatty acid esters
Tan, Xuefeng,Wang, Yan,Liu, Yuanhua,Wang, Fangyuan,Shi, Liyang,Lee, Ka-Ho,Lin, Zhenyang,Lv, Hui,Zhang, Xumu
, p. 454 - 457 (2015)
A new tetradentate ruthenium complex has been developed for hydrogenation of esters. The catalysts structure features a pyridinemethanamino group and three tight chelating five-membered rings. The structure character is believed to be responsible for its high stability and high carbonylation-resistant properties. Thus, this catalyst shows outstanding performance in the catalytic hydrogenation of a variety of esters, especially for fatty acid esters, which may be used in practical applications. New insight on designing hydrogenation catalyst for reducing esters to alcohols has been provided through theoretical calculations.
Copper(ii) induced oxidative modification and complexation of a schiff base ligand: Synthesis, crystal structure, catalytic oxidation of aromatic hydrocarbons and DFT calculation
Biswas, Surajit,Dutta, Arpan,Dolai, Malay,Debnath, Mainak,Jana, Atish Dipankar,Ali, Mahammad
, p. 34248 - 34256 (2014)
A mononuclear square planar complex [CuII(Lf)] (1) was synthesized and structurally characterized by single crystal X-ray diffraction studies. Though we have started with the Schiff base H 2La with two -CH2
Palladium-catalyzed hydrodehalogenation of aryl halides using paraformaldehyde as the hydride source: High-throughput screening by paper-based colorimetric iodide sensor
Pyo, Ayoung,Kim, Sudeok,Kumar, Manian Rajesh,Byeun, Aleum,Eom, Min Sik,Han, Min Su,Lee, Sunwoo
, p. 5207 - 5210 (2013)
Paraformaldehyde was employed as a hydride source in the palladium-catalyzed hydrodehalogenation of aryl iodides and bromides. High throughput screening using a paper-based colorimetric iodide sensor (PBCIS) showed that Pd(OAc)2 and Cs2CO3 were the best catalyst and base, respectively. Aryl iodides and bromides were hydrodehalogenated to produce the reduced arenes using Pd(OAc)2 and Pd(PPh3)4 catalyst. This catalytic system showed good functional group tolerance. In addition, it was found that paraformaldehyde is the hydride source and the reducing agent for the formation of palladium nanoparticles.
A New Approach for Oxygenation Using Nitric Oxide under the Influence of N-Hydroxyphthalimide
Eikawa, Masahiro,Sakaguchi, Satoshi,Ishii, Yasutaka
, p. 4676 - 4679 (1999)
An approach for partial oxygenation through a carbocation as an intermediate was successfully developed by using nitric oxide under the influence of N-hydroxyphthalimide. Thus, a variety of benzylic ethers were converted into the corresponding partially oxidized compounds, which are difficult to prepare by conventional methods, in high yields. For example, the reaction of phthalane with NO in the presence of a catalytic amount of NHPI at 60°C gave phthalaldehyde in 80% yield. The reaction was found to proceed through the formation of a hemiacetal, such as 1-hydroxyphthalane. In addition, 1,3-di-tert-butoxymethyl benzene afforded 1,3-benzenedicarbaldehyde in good yield. On the other hand, isochroman was converted into 1,1′-oxodiisochromane under these reaction conditions. The reaction of ethers with NO in the presence of a NHPI catalyst is thought to proceed via the formation of a carbocation as an intermediate. A possible reaction path was suggested.
One-pot double benzylation of 2-substituted pyridines using palladium-catalyzed decarboxylative coupling of sp2 and sp3 carbons
Wang, Yaping,Li, Xinjian,Leng, Faqiang,Zhu, Helong,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
, p. 3307 - 3313 (2014)
An efficient and practical decarboxylative double benzylation method for various 2-picolinic acids has been established by using a bimetallic catalytic system of palladium(II) chloride (PdCl2) and silver(I) oxide (Ag2O), which offered a variety of diarylmethane derivatives with moderate to good yields.
Nitration of alkanes with nitric acid by vanadium-substituted polyoxometalates
Shinachi, Satoshi,Yahiro, Hidenori,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 6489 - 6496 (2004)
The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium-substituted Keggin-type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H 6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carbon-carbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium-substituted polyoxometalate, for example, [H4PVMo 11O40], decomposes to form free vanadium species and [PMo12O40]3- Keggin anion. The reaction mechanism involving a radical-chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O 40]n-, and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.
Effects of the carbon support nature and ruthenium content on the performances of Ru/C catalysts in the liquid-phase hydrogenation of benzaldehyde to benzyl alcohol
Mironenko, Roman M.,Belskaya, Olga B.,Zaikovskii, Vladimir I.,Likholobov, Vladimir A.
, p. 923 - 930 (2015)
Abstract The hydrogenation of benzaldehyde in ethanol medium in the presence of Ru/C catalysts was shown to proceed with the preferential formation of benzyl alcohol without subsequent hydrodeoxygenation into toluene. An increase in ruthenium content of t
New CNN-type ruthenium pincer NHC complexes. Mild, efficient catalytic hydrogenation of esters
Fogler, Eran,Balaraman, Ekambaram,Ben-David, Yehoshua,Leitus, Gregory,Shimon, Linda J.W.,Milstein, David
, p. 3826 - 3833 (2011)
Figure Presented: New pincer ruthenium complexes (2-6) based on the new bipyridine-NHC ligand 1 were prepared and studied, resulting in an efficient catalytic hydrogenation of esters to the corresponding alcohols under mild conditions. Reaction of the ligand 1 with RuH(Cl)CO(PPh3) 3, followed by reaction with one equivalent of the base KHMDS, gave the mixed phosphine-NHC complex 2, incorporating a C-H-activated bipyridine ligand. Complex 2 has an octahedral structure containing two phosphorus atoms trans to each other, a hydride trans to the NHC ligand, and CO trans to the C-H-activated carbon of the bipyridine ligand. Using the precursor complex Ru(p-cymene)Cl2(CO), reaction with 1 followed by treatment of the intermediate product with one equivalent of KHMDS resulted in formation of the dichloride pincer complexes 3a and 3b, which are in equilibrium, as indicated by variable-temperature 1H NMR. Complex 3a is an octahedral, neutral, and symmetric complex with the CO ligand positioned trans to the central pyridine group of the pincer ligand and the two chlorides trans to each other, as indicated by single-crystal X-ray diffraction. Complex 3b is cationic, with an outer-sphere chloride. Reaction of the NHC ligand 1 with LiHMDS at low temperature followed by addition of RuH(Cl)CO(PPh3)3 resulted in the mixed phosphine-NHC complex 4, which has an octahedral structure containing phosphorus trans to the hydride, a CO trans to the NHC ligand, and an outer-sphere chloride. Chloride substitution by BArF- gave the X-ray-characterized complex 5. Deprotonation of complex 4 with KHMDS resulted in formation of the dearomatized complex 6. The in situ prepared 6 (from complex 4 and an equivalent of base) is among the best catalysts known for the hydrogenation of nonactivated esters to the corresponding alcohols under mild conditions.
n-Butyllithium (1 mol %)-catalyzed Hydroboration of Aldehydes and Ketones with Pinacolborane
Yang, Su Jin,Jaladi, Ashok Kumar,Kim, Jea Ho,Gundeti, Shankaraiah,An, Duk Keun
, p. 34 - 38 (2019)
A practical and efficient protocol for the hydroboration of aldehydes and ketones using a pinacolborane and alkyl lithium system is demonstrated. A systematic evaluation showed that 1 mol % n-butyllithium afforded catalyzed hydroboration of aldehydes and ketones in a short reaction time under ambient conditions. Excellent yield, functional group tolerance, short reaction time, low catalyst loading, and gram-scale synthesis are the salient features of the proposed protocol.
Design of mesoporous aluminosilicates supported (1R,2S)-(-)-ephedrine: Evidence for the main factors influencing catalytic activity in the enantioselective alkylation of benzaldehyde with diethylzinc
Abramson,Lasperas,Brunel
, p. 357 - 367 (2002)
(-)-Ephedrine, used as a model β-amino alcohol, was covalently anchored on mesoporous micelle templated aluminosilicates (Al-MTS) through nucleophilic substitution of halogenoalkyl(aryl)silane chains previously grafted on the surface. The covalent graftin
Deamination of N,O-Dialkylhydroxylamines via N-Nitroso-N,O-dialkylhydroxylamines: a New Reaction
Maskill, H.,Menneer, Iain D.,Smith, David I.
, p. 1855 - 1856 (1995)
N-Nitroso-N,O-dialkylhydroxylamines undergo acid catalysed deaminative solvolysis in aqueous solution.
Why does alkylation of the N-H functionality within M/NH bifunctional Noyori-type catalysts lead to turnover?
Dub, Pavel A.,Scott, Brian L.,Gordon, John C.
, p. 1245 - 1260 (2017)
Molecular metal/NH bifunctional Noyori-type catalysts are remarkable in that they are among the most efficient artificial catalysts developed to date for the hydrogenation of carbonyl functionalities (loadings up to ～10-5 mol %). In addition, these catalysts typically exhibit high C=0/C=C chemo- and enantioselectivities. This unique set of properties is traditionally associated with the operation of an unconventional mechanism for homogeneous catalysts in which the chelating ligand plays a key role in facilitating the catalytic reaction and enabling the aforementioned selectivities by delivering/accepting a proton (H+) via its N-H bond cleavage/formation. A recently revised mechanism of the Noyori hydrogenation reaction (Dub, P. A et al. J. Am. Chem. Soc. 2014,136,3505) suggests that the N-H bond is not cleaved but serves to stabilize the turnover-determining transition states (TDTSs) via strong N-H···O hydrogen-bonding interactions (HBIs). The present paper shows that this is consistent with the largely ignored experimental fact that alkylation of the N-H functionality within M/NH bifunctional Noyori-type catalysts leads to detrimental catalytic activity. The purpose of this work is to demonstrate that decreasing the strength of this HBI, ultimately to the limit of its complete absence, are conditions under which the same alkylation may lead to beneficial catalytic activity.
Oxidation of toluene and other examples of Ci￡H bond activation by CdO2 and ZnO2 nanoparticles
Lingampalli,Gupta, Uttam,Gautam, Ujjal K.,Rao
, p. 837 - 842 (2013)
Nanoparticles of CdO2 and ZnO2 are shown to oxidize toluene primarily to benzaldehyde in the 160-180 °C range, around which temperature the nanoparticles decompose to give the oxides. The product selectivity and other features of the
Acetonyltriphenylphosphonium bromide and its polymer-supported analogues as catalysts in protection and deprotection of alcohols as alkyl vinyl ethers
Hon, Yung-Son,Lee, Chia-Fu,Chen, Rong-Jiunn,Szu, Ping-Hui
, p. 5991 - 6001 (2001)
Both acetonyltriphenylphosphonium bromide (ATPB, 1) and poly-p-styryldiphenylacetonylphosphonium bromide (A) were effective catalysts in the protection of alcohols as THP, THF, and EE ethers as well as the cleavage of THP, THF, and EE ethers to the corresponding alcohols. They could be applied to 1°, 2° and 3° alcohols, phenol and acid-labile alcohols. Both ATPB and catalyst A are excellent catalysts in the present study. It needed only 1×10-2-1.25×10-2 mol equiv. of the polymer-supported catalyst A in the reactions.
Highly chemoselective reduction of imines using a AuNPore/PhMe2SiH/water system and its application to reductive amination
Takale, Balaram S.,Tao, Shanmou,Yu, Xiaoqiang,Feng, Xiujuan,Jin, Tienan,Bao, Ming,Yamamoto, Yoshinori
, p. 7154 - 7158 (2015)
Abstract An unusually strong affinity of unsupported nanoporous gold (AuNPore) towards aldimines and ketimines has been demonstrated. By using PhMe2SiH and water as a hydrogen source and AuNPore as a catalyst, ketimines and aldimines can be reduced to the corresponding amines in high chemical yields under mild conditions. This system was also applied to the reductive amination of aldehydes and ketones.
Transfer Hydrogenation of Ketones and Imines with Methanol under Base-Free Conditions Catalyzed by an Anionic Metal-Ligand Bifunctional Iridium Catalyst
Han, Xingyou,Li, Feng,Liu, Peng,Wang, Rongzhou,Xu, Jing
, p. 2242 - 2249 (2020)
An anionic iridium complex [Cp*Ir(2,2′-bpyO)(OH)][Na] was found to be a general and highly efficient catalyst for transfer hydrogenation of ketones and imines with methanol under base-free conditions. Readily reducible or labile substituents, such as nitro, cyano, and ester groups, were tolerated under present reaction conditions. Notably, this study exhibits the unique potential of anionic metal-ligand bifunctional iridium catalysts for transfer hydrogenation with methanol as a hydrogen source.
Hydrogenation of Esters by Manganese Catalysts
Li, Fu,Li, Xiao-Gen,Xiao, Li-Jun,Xie, Jian-Hua,Xu, Yue,Zhou, Qi-Lin
, (2022/01/13)
The hydrogenation of esters catalyzed by a manganese complex of phosphine-aminopyridine ligand was developed. Using this protocol, a variety of (hetero)aromatic and aliphatic carboxylates including biomass-derived esters and lactones were hydrogenated to primary alcohols with 63–98% yields. The manganese catalyst was found to be active for the hydrogenation of methyl benzoate, providing benzyl alcohol with turnover numbers (TON) as high as 45,000. Investigation of catalyst intermediates indicated that the amido manganese complex was the active catalyst species for the reaction. (Figure presented.).
Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis
Li, Han,Wenger, Oliver S.
supporting information, (2021/12/23)
The two-electron reduced forms of perylene diimides (PDIs) are luminescent closed-shell species whose photochemical properties seem underexplored. Our proof-of-concept study demonstrates that straightforward (single) excitation of PDI dianions with green
3D structured TiO2-based aerogel photocatalyst for the high-efficiency degradation of toluene gas
Dai, Li,Guan, Jie,Li, Shijie,Li, Xueying,Yu, Wei,Zhang, Li
, p. 2272 - 2281 (2022/02/16)
Photocatalytic technology is a green , environmentally friendly, energy-saving technology, which is considered to be an ideal method for removing volatile organic compounds (VOCs). At present, photocatalytic technology mostly uses powdered catalysts, which is not conducive to recycling and restricts the contact between the gas and catalyst. In this work, a three-dimensional (3D)-structured TiO2-based aerogel with TiO2 as the main body and all the components beneficial to photocatalysis was prepared for the first time. Under simulated sunlight irradiation, the toluene-removal rate of the Pt-loaded TiO2 and reduced graphene oxide (RGO) composite aerogel (denoted as Pt-TiO2/RGO aerogel, or PTA thereafter) was 60.47% higher than that of the pure RGO aerogel, and 56.03% higher than that of the bare TiO2 nanofibers. The block-shaped composite aerogel could be easily recycled, and the C/C0 of toluene using the recycled sample decreased by only 5.31% in the 5th run. The Pt-TiO2/RGO composite aerogel had the highest photocatalytic degradation rate of toluene with a relative humidity (RH) of 60-80%, which is conducive to the purification of VOCs in high-humidity areas. The 3D aerogel enriches the contact between the solid photocatalyst and the toluene molecules, and also solves the problem of low adhesion between the catalyst and the carrier. This work provides a new perspective for the efficient removal of toluene gas by constructing a highly active 3D TiO2 aerogel with an increased gas-solid reaction rate.
