- Ethoxysilane appended M(II) complexes and their SiO2/MCM-41 supported forms as catalysts for efficient oxidation of secondary alcohols
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Divalent transition metal complexes ML2 (M = Mn 1; Co 2; Cu 3; Zn 4), possessing an ethoxysilane group as a part of the bidentate Schiff base ((E)-1-((3-(triethoxysilyl)propylimino)methyl)naphthalen-2-ol (L)), have been synthesized. While the copper complex 3 has been isolated in an analytically pure form and characterized by spectroscopic and single crystal XRD studies, the formation of complexes 1, 2, and 4 in solution has been verified by ESI mass spectroscopy and subsequently used for further catalyst preparation without their isolation. Treatment of the in situ formed 1–4 with pre-activated silica in boiling toluene produces the catalysts 5–8, respectively. The copper complex 3 was also treated with MCM-41 in boiling toluene to obtain CuL2@MCM-41 (9). Elemental analysis (CHN), ESI MS, IR, UV–vis., 13C & 29Si NMR, EPR, P-XRD, TGA, BET, SEM and TEM have been used to characterize the compounds. Compounds 3 (homogeneous) and 5–9 (heterogeneous) have been utilized as catalysts in the oxidation of secondary alcohols to corresponding carbonyls in the presence of H2O2, t-BuOOH, and C6H5C(CH3)2OOH. 3 and 9 have shown better catalytic activity than the rest of the catalysts investigated. Combination of 9 with H2O2 is the best catalytic system due to its efficiency and reusability besides being environment friendly.
- Antony, Rajendran,Marimuthu, Rajendiran,Vishnoi, Pratap,Murugavel, Ramaswamy
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- Photooxygenation of 1,1-Diarylethylenes via Addition of Oxygen to the 1,4-Dimer Radical Cations, Catalyzed by 10-Methylacridinium Ion
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Photooxygenation of 1,1-diarylethylene occurs efficiently using 10-methylacridinium ion as a photocatalyst to yield the 1,2-dioxane and/or the diaryl ketone depending on the substituents on the aryl groups. The reaction mechanism is revealed based on the dependence of the quantum yields on the concentrations of the alkene and oxygen, the fluorescence quenching of 10-methylacridinium ion by the alkene, and the direct detection of reactive intermediates by applying laser flash spectroscopy as well as pulse radiolysis. The photooxygenation proceeds via photoinduced electron transfer from the alkene to the singlet excited state of 10-methylacridinium ion. The alkene radical cation formed by the photoinduced electron transfer reacts with alkene to give the 1,4-dimer radical cation, which then reacts with oxygen to produce the oxygenated 1,6-radical cation. The subsequent one-electron reduction of the 1,6-radical cation results in formation of the 1,6-biradical which cyclizes to yield 1,2-dioxane derivative or fragmentates to yield diaryl ketone. When the 1,6-biradical is reduced by the alkene itself, the alkene radical cation is regenerated to repeat the radical chain process.
- Fujita, Morifumi,Shindo, Akira,Ishida, Akito,Majima, Tetsuro,Takamuku, Setsuo,Fukuzumi, Shunichi
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- Mechanism of Photochemical Reaction of Contact Charge Transfer Pair between 1,1-Diarylethene and Oxygen
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Selective excitation of the contact charge transfer band between 1,1-diarylethene and oxygen in dichloromethane and acetonitrile gave 3,3,6,6-tetraaryl-1,2-dioxane and benzophenone derivative through an electron transfer reaction.The proposed mechanism was confirmed by the direct observation of the dimer cation radical of the olefin trapped by a triplet oxygen in pulse radiolysis.
- Kojima, Masanobu,Ishida, Akito,Takamuku, Setsuo
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- Investigations of the Influence of Molecular Geometry on the Spectroscopic and Photochemical Properties of α-Oxoparacyclophanes (Cyclophanobenzophenones)
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The spectroscopic and photochemical properties of a family of α-oxoparacyclophanes (8-12) for n=8-12, respectively) have been investigated.Compared to a model structure possessing a nominal T1(n?*) state (4,4'-dimethylbenzophenone, DM-BZ), photochemical and photophysical evidence is presented that the n?* character of T1 decreases as the cyclophane ring size decreases.For example, the rate constants for hydrogen atom abstraction from 1,4-cyclohexadiene in acetonitrile are 1.6E8, 0.93E8, 0.30E8, 0.06E8, and 0.04E8 M-1s-1 for triplet 12-8, respectively, a result consistent with decreasing n?* character and decreasing reactivity toward hydrogen atom abstraction with decreasing value of n.The spectroscopic properties (vibrational structure of the phosphorescence spectrum, phosphorescence lifetime, phosphorescence excitation spectra, triplet-triplet absorption spectra) also vary in a manner consistent with decreasing n?* character as the cyclophane ring size decreases.
- Turro, Nicholas J.,Gould, Ian R.,Liu, Jennifer,Jenks, William S.,Staab, Heinz,Alt, Reinhold
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- Preparation method of diaryl ketone
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The invention relates to the field of organic compound preparation chemistry, and particularly discloses a preparation method of diaryl ketone. The preparation method comprises the following steps: reacting tartrate with an aryl Grignard reagent to prepare 1,1,4,4-tetraaryl butantetraol; the method comprises the following steps: in the presence of an organic alkali and under a specific temperature condition, carrying out a highly regioselective 2, 3-cyclic sulfite esterification reaction on the 1,1,4,4-tetraaryl butantetraol and thionyl chloride to generate dichloro aryl cyclic sulfite; and reacting the dichloro aryl cyclic sulfite with inorganic alkali liquor at a certain temperature in a certain organic solvent to generate the diaryl ketone. The preparation method avoids the use of an expensive heavy metal-containing catalyst, and has the remarkable characteristics of easily available raw materials, simplicity and convenience in operation, excellent reaction region selectivity, easiness in treatment, high yield and the like.
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- Visible-Light-Driven Selective Air-Oxygenation of C?H Bond via CeCl3 Catalysis in Water
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Visible-light-induced C?H aerobic oxidation is an important chemical transformation that can be applied for the synthesis of aromatic ketones. High-cost catalysts and toxic solvents were generally needed in the present methodologies. Here, an efficient aqueous C?H aerobic oxidation protocol was reported. Through CeCl3-mediated photocatalysis, a series of aromatic ketones were produced in moderate to excellent yields. With air as the oxidant, this reaction could be performed under mild conditions in water and demonstrated high activity and functional group tolerance. This method is economical, highly efficient, and environmentally friendly, and it will provide inspiration for the development of aqueous photochemical synthesis reactions.
- Xie, Pan,Xue, Cheng,Shi, Sanshan,Du, Dongdong
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p. 2689 - 2693
(2021/05/07)
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- Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
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Irradiated by visible light, the recyclable (PhTe)2-catalyzed oxidative deoximation reaction could occur under mild conditions. In comparison with the thermo reaction, the method employed reduced catalyst loading (1 mol% vs. 2.5 mol%), but afforded elevated product yields with expanded substrate scope. This work demonstrated that for the organotellurium-catalyzed reactions, visible light might be an even more precise driving energy than heating because it could break the Te–Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents (e.g., heterocycles) of substrates. The use of O2 instead of explosive H2O2 as oxidant affords safer reaction conditions from the large-scale application viewpoint.
- Deng, Xin,Qian, Rongrong,Zhou, Hongwei,Yu, Lei
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supporting information
p. 1029 - 1032
(2020/10/23)
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- PhSe(O)OH/NHPI-catalyzed oxidative deoximation reaction using air as oxidant
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A novel oxidative deoximation method was developed in this article. Compared with the reported organoselenium-catalyzed oxidative deoximation reaction, this reaction employed N-hydroxyphthalimide (NHPI) as the co-catalyst, so that the oxidative deoximation reaction could utilize air as oxidant in the green DMC solvent under mild reaction conditions. Control experiments and X-ray photoelectron spectroscopy (XPS) analysis results indicated that NHPI was essential for activating the catalytic organoselenium species. It could accelerate the activation of molecular oxygen in air to promote the reaction process. The reaction can avoid metal residues in product and is of potential application values in pharmaceutical industry due to the transition metal-free process.
- Shi, Yaocheng,Wang, Feng,Yang, Chenggen,Yu, Lei
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- Fe-S Catalyst Generated in Situ from Fe(III)- And S3?--Promoted Aerobic Oxidation of Terminal Alkenes
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An iron-sulfur complex formed by the simple mixture of FeCl3 with S3?- generated in situ from K2S is developed and applied to selective aerobic oxidation of terminal alkenes. The reaction was carried out under an atmosphere of O2 (balloon) and could proceed on a gram scale, expanding the application of S3?- in organic synthesis. This study also encourages us to explore the application of an Fe-S catalyst in organic reactions.
- Ai, Jing-Jing,Huang, Cheng-Mi,Li, Jian,Liu, Bei-Bei,Rao, Weidong,Wang, Fei,Wang, Shun-Yi
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supporting information
p. 4705 - 4709
(2021/06/28)
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- Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanoneviaCeCl3catalysis
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A Ce-catalyzed strategy is developed to produce biaryl methanonesviaphotooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
- Xie, Pan,Xue, Cheng,Du, Dongdong,Shi, SanShan
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supporting information
p. 6781 - 6785
(2021/08/20)
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- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
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With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
- Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
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p. 5936 - 5943
(2021/08/23)
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- Palladium nanoparticles on amino-modified silica-catalyzed C–C bond formation with carbonyl insertion
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Abstract: A practical and heterogeneously catalyzed Stille, homo-coupling, and Suzuki carbonylation reaction has been reported using Pd nanoparticles supported on amino-vinyl silica-functionalized magnetic carbon nanotube (CNT@Fe3O4@SiO2-Pd) for the efficient synthesis of symmetrical and unsymmetrical diaryl ketones from aryl iodides. A wide variety of symmetrical and unsymmetrical diaryl ketones were obtained in high yields under CO gas-free conditions using Mo(CO)6 as an efficient carbonyl source. Considering the atom economy of Ph3SnCl, less than an equimolar amount can be applied in Stille transformation, which is of great importance due to the toxicity of organotin derivatives. Moreover, no phosphine ligand and external reducing agent were necessary in these coupling carbonylation reactions. This heterogeneous Pd catalyst offers high activity with very low palladium leaching. Finally, the catalyst can be reused and recycled for six steps without loss in activity, exhibiting good example of sustainable methodology. Graphic abstract: [Figure not available: see fulltext.].
- Etemadi-Davan, Elham,Khalili, Dariush,Banazadeh, Ali Reza,Sadri, Ghazal,Arshad, Pourya
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p. 1891 - 1903
(2021/02/01)
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- Palladium imine-pyridine-imine complex immobilized on graphene oxide as a recyclable catalyst for the carbonylative homo-coupling of aryl halides
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A heterogeneous 3-N,N,N-(II) Pd(OAc)2 catalyst was prepared from the reaction of Pd(OAc)2 with Si-Prn-N = C-Py-C = N-Prn-Si immobilized on graphene oxide (GO-Si-Prn-N = C-Py-C = N-Prn-Si-GO). The prepared catalyst was characterized by inductively coupled plasma optical emission spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, UV-vis spectroscopy, BET surface area, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The catalyst was employed as a heterogeneous catalyst for carbonylative homo-coupling of aryl iodides and bromides under carbon monoxide gas-free condition. Cr(CO)6 was used as the carbon monoxide source and the desired symmetrical diaryl ketones were achieved in good to excellent yields. Moreover, the catalyst was reused up to five consecutive cycles without significant loss of activity.
- Niakan, Mahsa,Asadi, Zahra,Khosrozadeh, Fatemeh
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p. 850 - 863
(2020/12/18)
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- Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
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Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
- Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
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p. 2084 - 2092
(2021/04/02)
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- Suzuki-Miyaura cross-coupling of esters by selective O-C(O) cleavage mediated by air- And moisture-stable [Pd(NHC)(μ-Cl)Cl]2precatalysts: Catalyst evaluation and mechanism
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The cross-coupling of aryl esters has emerged as a powerful platform for the functionalization of otherwise inert acyl C-O bonds in chemical synthesis and catalysis. Herein, we report a combined experimental and computational study on the acyl Suzuki-Miyaura cross-coupling of aryl esters mediated by well-defined, air- and moisture-stable Pd(ii)-NHC precatalysts [Pd(NHC)(μ-Cl)Cl]2. We present a comprehensive evaluation of [Pd(NHC)(μ-Cl)Cl]2 precatalysts and compare them with the present state-of-the-art [(Pd(NHC)allyl] precatalysts bearing allyl-type throw-away ligands. Most importantly, the study reveals [Pd(NHC)(μ-Cl)Cl]2 as the most reactive precatalysts discovered to date in this reactivity manifold. The unique synthetic utility of this unconventional O-C(O) cross-coupling is highlighted in the late-stage functionalization of pharmaceuticals and sequential chemoselective cross-coupling, providing access to valuable ketone products by a catalytic mechanism involving Pd insertion into the aryl ester bond. Furthermore, we present a comprehensive study of the catalytic cycle by DFT methods. Considering the clear advantages of [Pd(NHC)(μ-Cl)Cl]2 precatalysts on several levels, including facile one-pot synthesis, superior atom-economic profile to all other Pd(ii)-NHC catalysts, and versatile reactivity, these should be considered as the 'first-choice' catalysts for all routine applications in ester O-C(O) bond activation.
- Cavallo, Luigi,Nolan, Steven P.,Poater, Albert,Szostak, Michal,Yang, Shiyi,Zhou, Tongliang
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p. 3189 - 3197
(2021/05/25)
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- Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
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The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
- Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
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p. 10455 - 10466
(2021/07/31)
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- Tetra- And Dinuclear Palladium Complexes Based on a Ligand of 2,8-Di-2-pyridinylanthyridine: Preparation, Characterization, and Catalytic Activity
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Complexation of L [L = 5-phenyl-2,8-di-2-pyridinyl-anthyridine] with [Pd(CH3CN)4](BF4)2 and [Pd(CH3CN)3Cl](BF4) in a molar ratio of 1:2 rendered the corresponding dinuclear complexes [Pd2L (CH3CN)4](BF4)4 (1) and [Pd2L (CH3CN)2Cl2](BF4)2 (2), respectively. However, treatment of L with (COD)PdCl2 followed by anion exchange yielded a tetranuclear complex [Pd4L3Cl4](PF6)4(4a). Structures of these complexes are characterized by both spectroscopy and X-ray crystallography. Interconversion of these three complexes was studied via the manipulation of stoichiometric ratio of ligand to metal precursor. The catalytic activity of these complexes for carbonylative Suzuki-Miyaura cross-coupling was investigated. Complex 2 shows an excellent catalytic activity on the reaction of aryl iodide with arylboronic acid in the presence of atmospheric pressure of CO to give the corresponding benzophenones.
- Lin, Shih-Chieh Aaron,Liu, Shiuh-Tzung,Liu, Yi-Hung,Peng, Shie-Ming,Su, Bo-Kai
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p. 2081 - 2089
(2021/07/26)
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- Ruthenium-Catalyzed Dehydrogenation of Alcohols with Carbodiimide via a Hydrogen Transfer Mechanism
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Ruthenium-catalyzed oxidative dehydrogenation of alcohols using carbodiimide as an efficient hydrogen acceptor has been developed. The protocol exhibits wide substrate scope with good to excellent yields. The results of the kinetic analysis indicated that the reaction mechanism includes the hydrogen transfer process and that the addition of carbodiimide is essential for the reaction system, and the resulting amidine also could react as a hydrogen acceptor.
- Sueki, Shunsuke,Matsuyama, Mizuki,Watanabe, Azumi,Kanemaki, Arata,Katakawa, Kazuaki,Anada, Masahiro
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p. 4878 - 4885
(2020/06/02)
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- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
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A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
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p. 12443 - 12446
(2020/10/30)
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- Photo-induced phosphorus radical involved semipinacol rearrangement reaction: Highly synthesis of γ-oxo-phosphonates
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Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
- Wang, Chunhai,Huang, Xiaoling,Liu, Xueting,Gao, Suqian,Zhao, Bin,Yang, Shangdong
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supporting information
p. 677 - 680
(2019/08/27)
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- Synthesis, characterization, antibacterial activity and molecular docking studies on triazolophanes with benzophenone and S(-)-BINOL functionalization at the intra annular position
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Triazolophanes with benzophenone and S(-)-BINOL functionalization at the intra annular position have been synthesized by the click reaction of 4,4′-bis(azidomethyl) benzophenone with the corresponding bispropargyloxy compounds. The newly synthesized triazolophanes were characterized by spectral and analytical methods. Triazolophane with S(-)-BINOL and benzophenone functionality at the intra annular position shows good target binding ability in molecular docking studies and also better antibacterial activity against all the four tested pathogens viz. Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, and Escherichia coli bacteria.
- Saravanan, Velautham,Rajakumar, Perumal
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p. 2461 - 2477
(2020/07/07)
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- A metal-free heterogeneous photocatalyst for the selective oxidative cleavage of CC bonds in aryl olefins: via harvesting direct solar energy
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Selective cleavage of CC bonds is highly important for the synthesis of carbonyl containing fine chemicals and pharmaceuticals. Novel methodologies such as ozonolysis reactions, Lemieux-Johnson oxidation reaction etc. already exist. Parallel to these, catalytic methods using homogeneous catalysts also have been discovered. Considering the various advantages of heterogeneous catalysts such as recyclability and stability, couple of transition metal-based heterogeneous catalysts have been applied for this reaction. However, the pharmaceutical industries prefer to use metal-free catalysts (especially transition metal-free) to avoid further leaching in the final products. This is for sure a big challenge to an organic chemist and to the pharmaceutical industries. To make this feasible, a mild and efficient protocol has been developed using polymeric carbon nitrides (PCN) as metal-free heterogeneous photocatalysts to convert various olefins into the corresponding carbonyls. Later, this catalyst has been applied in the gram scale synthesis of pharmaceutical drugs using direct solar energy. Detailed mechanistic studies revealed the actual role of oxygen, the catalyst, and the light source.
- Das, Shoubhik,Hatami, Nareh,Jooss, Christian,Lange, Niklas Simon,Ronge, Emanuel,Schilling, Waldemar,Zhang, Yu
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supporting information
p. 4516 - 4522
(2020/08/10)
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- Carbonylative Suzuki coupling reactions catalyzed by ONO pincer–type Pd(II) complexes using chloroform as a carbon monoxide surrogate
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Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL1(PPh3)] (1), [(PdL2(PPh3)] (2), and [(PdL3(PPh3)] (3), were synthesized by the reaction of the respective ligand, N-(2-hydroxybenzylidene)benzohydrazide (HL1), N-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (HL2), or N-(5-bromo-2-hydroxybenzylidene) benzohydrazide (HL3), with Pd(OAc)2 and PPh3 in methanol and isolated as air-stable reddish-orange crystalline solids in high yields (78%–83%). All three complexes were fully characterized by elemental analysis, Fourier-transform infrared spectroscopy, UV–Visible, 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, and 31P{1H} NMR spectroscopic studies. The molecular structure of all three complexes was established unambiguously by single-crystal X-ray diffraction studies which revealed a distorted square planar geometry of all three complexes. The ONO pincer–type ligands occupied three coordination sites at the palladium, while the fourth site is occupied by the monodentate triphenylphosphine ligand. The catalytic potential of all three complexes was explored in the carbonylative Suzuki coupling of aryl bromides and iodides with arylboronic acids to yield biaryl ketones, using CHCl3 as the source of carbonyl. The reported protocol is convenient and safe as it obviates the use of carbon monoxide (CO) balloons or pressured CO reactors which are otherwise needed for the carbonylation reactions. The methodology has been successfully applied to the synthesis of two antineoplastic drugs, namely, phenstatin and naphthylphenstatin, in good yields (81% and 85%, respectively). Under the optimized reaction conditions, complex 2 exhibited the best catalytic activity in the carbonylative Suzuki couplings. The reported catalysts have wide reaction scope with good functional group tolerance. All catalysts could be retrieved from the reaction after completion and recycled up to three times with insignificant loss in the catalytic activity.
- Layek, Samaresh,Agrahari, Bhumika,Ganguly, Rakesh,Das, Parthasarathi,Pathak, Devendra D.
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- A palladium-catalyzed C-H functionalization route to ketones: Via the oxidative coupling of arenes with carbon monoxide
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We describe the development of a new palladium-catalyzed method to generate ketones via the oxidative coupling of two arenes and CO. This transformation is catalyzed by simple palladium salts, and is postulated to proceed via the conversion of arenes into high energy aroyl triflate electrophiles. Exploiting the latter can also allow the synthesis of unsymmetrical ketones from two different arenes.
- Arndtsen, Bruce A.,Kinney, R. Garrison,Levesque, Taleah M.
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p. 3104 - 3109
(2020/03/27)
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- Method for preparing epsilon-caprolactone by using in-situ peroxide
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The invention discloses a method for preparing epsilon-caprolactone by using in-situ peroxide. The method efficiently utilizes an in-situ peroxide obtained in a process of oxidizing alcohol by oxygento oxidize cyclohexanone into epsilon-caprolactone, i.e., under the catalysis of a catalyst, an alcohol is oxidized into the corresponding ketone while substances such as peroxy hydroxyl or hydrogen peroxide and the like generated in the process are fully utilized, so that the Baeyer Villiger oxidation reaction from cyclohexanone to epsilon-caprolactone is realized. Compared with a previous epsilon-caprolactone synthesis method, the method of the invention has the advantages that the product yield is remarkably increased, the use efficiency of alcohol is further improved, raw materials and reagents are cheap and easy to obtain, operation is easy, reaction conditions are mild, and the method is clean and environmentally friendly.
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Paragraph 0047-0049
(2020/12/30)
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- ε-Caprolactone manufacture via efficient coupling Baeyer-Villiger oxidation with aerobic oxidation of alcohols
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To avoid the use of peracids oxidant or highly concentrated hydrogen peroxide which is potentially hazardous and explosive, herein, a new route to ε-caprolactone was developed in which molecule oxygen was employed as the terminal oxidant. The commercial available N-hydroxyphthalimide and ammonium cerium nitrate were used as the key catalysts for the increased yield of ε-caprolactone. For instance, the selectivity of ε-caprolactone was obtained 92 % with 85 % conversion of cyclohexanone which was comparable to the strategies using highly concentrated hydrogen peroxide. The sacrificed alcohols were transformed into corresponding ketones which were also valuable chemicals. Furthermore, the efficiency of the alcohols was achieved to unprecedented 52 %. The Baeyer-Villiger oxidation of various other cycloalkanones was also examined. The substituent group effect on the efficiency of sacrificed alcohols was investigated in which weak electron-donating substituent induced nearly quantitative yield of ε-caprolactone. The reaction mechanism was studied with the help of electron paramagnetic resonance which indicated the existence of a radical pathway.
- Du, Renfeng,Li, Haoran,Wang, Yongtao,Yao, Jia,Yuan, Haoran,Zhao, Chenxuan
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- Photoinduced iodine-mediated tandem dehydrogenative Povarov cyclisation/C-H oxygenation reactions
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We report metal-free, photoinduced aerobic tandem dehydrogenative Povarov cyclisation/Csp3-H oxygenation reactions between N-aryl glycine esters and α-substituted styrenes, which efficiently lead to 4,4-disubstituted dihydroquinoline-3-ones under mild conditions. The reactions are mediated by iodine along with visible light irradiation, which allows for the in situ generation of the essential Br?nsted acid HI, to catalyse the key imine [4+2]-cycloaddition.
- Brasholz, Malte,Schendera, Eva,Villinger, Alexander
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supporting information
p. 6912 - 6915
(2020/10/02)
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- Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
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The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
- Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
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supporting information
p. 6187 - 6193
(2019/11/20)
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- A facile approach to constructing Pd@PCN-Se nano-composite catalysts for selective alcohol oxidation reactions
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By using selenium as the structure-directing agent, Se-incorporated polymeric carbon nitride (PCN-Se) was prepared for the first time and could be used as a superexcellent support for Pd nanoparticles (NPs). A trace amount of Se dopant (0.01 wt%) was found to play an unexpectedly vital role in increasing the materials' surface area and total mesoporous volume by 4.5 and 2 times respectively, so the Pd@PCN-Se catalyst might contain even more active sites than its simple PCN and Pd@PCN counterparts, and a strong interaction between Se(0) and Pd(ii) was also built-in, affording a dramatically improved catalytic activity as well as good recycling stability in selective catalytic alcohol oxidation reactions.
- Cao, Kuanhong,Deng, Xin,Chen, Tian,Zhang, Qitao,Yu, Lei
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supporting information
p. 10918 - 10923
(2019/05/17)
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- Cercosporin-bioinspired selective photooxidation reactions under mild conditions
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The development of an efficient system for selective oxidation of organic compounds to generate more valuable compounds with molecular oxygen is a significant challenge in industrial chemistry. Bioinspired by the ability of naturally occurring perylenequinonoid pigments (PQPs) to generate reactive oxygen species (ROS) upon photoirradiation, here we report that cercosporin, one of the perylenequinonoid pigments, can function as a cost-effective and environmentally friendly photocatalyst for a wide range of selective oxidations, including benzylic C-H bonds to carbonyls, amines to aldehydes, and sulfides to sulfoxides. All of the representative reactions proceeded smoothly with high efficiency under mild conditions. Owing to the use of inexpensive metal-free visible light-driven photocatalyst produced from microbial fermentation with cheap glucose as the starting material and the ease of handling, we expect that this developed method will be particularly attractive for many more applications in synthetic transformation.
- Li, Jia,Bao, Wenhao,Tang, Zhaocheng,Guo, Baodang,Zhang, Shiwei,Liu, Haili,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 6073 - 6081
(2019/11/20)
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- Sequential Organozinc Formation and Negishi Cross-Coupling of Amides Catalysed by Cobalt Salt
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Herein, a cobalt-catalysed Negishi-type cross-coupling of amide derivatives is described. Apart from being the first example of cobalt-catalysed Negishi-type coupling of amides, the process described employs a unique, simple, and cheap catalytic system to perform both the organozinc formation and the Negishi-type coupling. Indeed, the same cobalt(II) bromide salt used to form the arylzinc species from aryl bromides is then re-used to perform the cross coupling of this resulting arylzinc with N-benzoyl glutarimides at room temperature. The main advantages of the reaction presented are its robustness and ease of use. Indeed, the reactions of organozinc formation and Negishi-type coupling are performed without precautions toward water or oxygen. (Figure presented.).
- Dorval, Céline,Dubois, Elodie,Bourne-Branchu, Yann,Gosmini, Corinne,Danoun, Grégory
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p. 1777 - 1780
(2019/02/26)
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- Heterogeneous Suzuki-Miyaura coupling of heteroaryl ester: Via chemoselective C(acyl)-O bond activation
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A site-selective supported palladium nanoparticle catalyzed Suzuki-Miyaura cross-coupling reaction with heteroaryl esters and arylboronic acids as coupling partners was developed. This methodology provides a heterogeneous catalytic route for aryl ketone formation via C(acyl)-O bond activation of esters by successful suppression of the undesired decarbonylation phenomenon. The catalyst can be reused and shows high activity after eight cycles. The XPS analysis of the catalyst before and after the reaction suggested that the reaction might be performed via a Pd0/PdII catalytic cycle that began with Pd0.
- Ma, Hongpeng,Bai, Chaolumen,Bao, Yong-Sheng
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p. 17266 - 17272
(2019/06/24)
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- Method for preparing symmetric diarylketone through catalytic oxidative carbonylation
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The invention discloses a method for preparing symmetric diarylketone of a formula (I) as shown in the description. The method comprises the following steps: mixing arylboronic acid (II) (Ar-B(OH)2 (II)), a palladium catalyst, a promoter and an organic solvent in a reactor, introducing air and CO having a volume ratio of (7-19):1, reacting under the conditions of a pressure of 1-6 atm and a temperature of 30-80 DEG C for 8-16 hours, and performing after-treatment on the reaction solution, thereby obtaining the product symmetric diarylketone. According to the method disclosed by the invention,the air directly serves as an oxidizing agent to replace the O2 to be applied to oxidative carbonylation of the arylboronic acid, and the ratio of the air to CO is beyond an explosion limit. Therefore, the catalytic system is safe and economic. The palladium catalyst is small in dosage and simple in separation and can be recycled for several times. The method disclosed by the invention is mild inreaction condition, excellent in substrate suitability and high in yield.
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Paragraph 0023; 0024; 0025; 0026; 0028
(2019/03/08)
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- A Deoximation Method for Deprotection of Ketones and Aldhydes Using a Graphene-Oxide-Based Co-catalysts System
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The deoximation of a wide range of ketoximes and aldoximes to their corresponding carbonyl compounds with high yields has been achieved using graphene oxide (GO) and sodium nitrite (NaNO2) as highly efficient catalysts and air as the green oxidant under mild conditions. The mechanism of deprotection and recycling use of catalyst were revealed in deep experiment. The carboxylic acid groups on the GO were essential for high catalytic activity. (Figure presented.).
- Tong, Qiaolin,Liu, Yang,Gao, Xuezhi,Fan, Zhanfang,Liu, Tianfu,Li, Bo,Su, Dangsheng,Wang, Qinghe,Cheng, Maosheng
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supporting information
p. 3137 - 3145
(2019/05/01)
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- Iron-Enabled Utilization of Air as the Terminal Oxidant Leading to Aerobic Oxidative Deoximation by Organoselenium Catalysis
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In contrast to conventional organoselenium-catalyzed oxidation reactions that require peroxide oxidants such as hydrogen peroxide, in this work we found that, addition of a low loading of iron (II) could enable the successful utilization of air as the terminal oxidant in organoselenium-catalyzed oxidative deoximation reaction of ketoximes. This led to a new mild and relatively green aerobic oxidative deoximation method. Control reactions and X-ray photoelectron spectroscopy (XPS) analysis suggest that iron is crucial in the catalytic cycle, working to prohibit the deactivation of selenium catalyst through an iron-catalyzed aerobic oxidation of low valent selenium species by air to the active high valent selenium species. Since air can be utilized as the terminal oxidant, this work may contribute to the advance of organoselenium catalysis. (Figure presented.).
- Chen, Chao,Zhang, Xu,Cao, Hongen,Wang, Fang,Yu, Lei,Xu, Qing
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p. 603 - 610
(2018/12/14)
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- Ligand-free Palladium-Catalyzed Carbonylative Suzuki Coupling of Aryl Iodides in Aqueous CH3CN with Sub-stoichiometric Amount of Mo(CO)6 as CO Source
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A new method for the synthesis of diaryl and heterodiaryl ketones has been established based on the palladium-catalyzed carbonylative Suzuki coupling approach with sub-stoichiometric Mo(CO)6 as CO source. Using 0.5 mol% of Pd(TFA)2 as catalyst, 0.5 equivalent of Mo(CO)6 as solid carbonyl reagent and 3 equivalent of K3PO4 as base, a wide range of functionalized (hetero)aryl iodides and (hetero)aryl boronic acids could smoothly proceed the carbonylative cross-coupling reaction in aqueous CH3CN at 50 °C, affording the corresponding ketones in good to excellent yields. The newly developed method was easy to operate under mild conditions with high efficiency. (Figure presented.).
- Sun, Nan,Sun, Qingxia,Zhao, Wei,Jin, Liqun,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan
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p. 2117 - 2123
(2019/03/28)
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- Sodium Methyl Carbonate as an Effective C1 Synthon. Synthesis of Carboxylic Acids, Benzophenones, and Unsymmetrical Ketones
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Reported is the synthesis of carboxylic acids, symmetrical ketones, and unsymmetrical ketones with selectivity achieved by exploiting the differential reactivity of sodium methyl carbonate with Grignard and organolithium reagents.
- Hurst, Timothy E.,Deichert, Julie A.,Kapeniak, Lucas,Lee, Roland,Harris, Jesse,Jessop, Philip G.,Snieckus, Victor
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supporting information
p. 3882 - 3885
(2019/06/07)
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- Carbonylative Suzuki coupling and alkoxycarbonylation of aryl halides using palladium supported on phosphorus-doped porous organic polymer as an active and robust catalyst
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Developing highly active catalysts with the combined advantages of molecular and solid catalysis is considered as the “Holy Grail” in the area of catalysis research. Herein, a phosphorus-doped porous polymer-immobilized palladium was successfully developed as an efficient, robust, and recyclable catalyst for the carbonylative Suzuki coupling and alkoxycarbonylation reactions of aryl halides. Rather than just as an immobilizing molecular catalyst, palladium supported on phosphorus-doped porous organic polymer exhibits even better catalytic performances than that of its analogue homogeneous catalysts in both carbonylation reactions. Moreover, the catalyst can be easily separated and reused for at least 5 times without significant loss in reactivity. Importantly, the catalyst was highly stable under carbonylation reaction conditions, and no palladium nanoparticle was observed even after the 5th reuse.
- Wan, Yali,Song, Fangxiang,Ye, Tao,Li, Guangxing,Liu, Dingfu,Lei, Yizhu
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- Kinetic studies on tetrabutylammonium bromochromate oxidation of some mono-and di-substituted benzhydrols
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The oxidation of 12 mono- and di-substituted benzhydrols (BH) by tetrabutylammonium bromochromate (TBABC) have been studied in aqueous acetic acid medium. Absence of any effect of added acrylonitrile on the reaction discounts the possibility of a one-electron oxidation, leading to the formation of free radicals. The tetrabutylammonium bromochromate oxidation of 12 mono- and di-substituted benzhydrols complies with the isokinetic relationship and Hammett relationship. The overall mechanism is proposed to involve a cyclic concerted symmetrical transition state leading to the product.
- Hemalatha,Asghar, Basim H.,Mansoor, S Sheik
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p. 821 - 826
(2018/03/13)
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- Synthesis, structure and catalytic alcohol oxidation by ruthenium(III) supported by Schiff base and triphenylphosphine ligands
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Treatment of [RuCl2(PPh3)3] with two equiv. bi-dentate Schiff base N,O-LH-Cl (N,O-LH-Cl = 2[(3-chloro-phenylimino)-methyl]-phenol) or N,O-LH-NO2 (N,O-LH-NO2 = 2[(4-nitro-phenylimino)-methyl]-phenol) in the presence of triethylamine afforded cis-[RuCl(PPh3)(κ2-N,O-L-Cl)2] (1) and trans-[RuCl(PPh3)(κ2-N,O-L-NO2)2]·Et2O (2), respectively. Reactions of [RuCl2(PPh3)3] and equal equiv. tetra-dentate Schiff bases gave corresponding ruthenium(III) complexes [RuCl(PPh3)(salen)] (3) (H2salen = N,N′-disalicylidene-1,2-ethanediamine), [RuCl(PPh3)(salipn)]·2CH2Cl2 (4) (H2salipn = N,N′-disalicylidene-1,2-(1-methyl)ethanediamine), [RuCl(PPh3)(salpn)]·CH2Cl2 (5) (H2salpn = N,N′-disalicylidene-1,2-propanediamine), [RuCl(PPh3)(salphen)]·CH2Cl2 (6) (H2salphen = N,N′-disalicylidene-1,2-phenyldiamine), [RuCl(PPh3)(saltoln)]·CH2Cl2 (7) (H2saltoln = N,N′-disalicylidene-1,2-tolyldiamine) and [RuCl(PPh3)(salcyn)] (8) (H2salcyn = N,N′-disalicylidene-(R,R)-1,2-cyclohexanediamine). The molecular structures of complexes 1–5 and 7 have been determined by single-crystal X-ray crystallography. The catalytic oxidation properties of ruthenium(III) complexes 1–8 were tested towards alcohols in the presence of N-methylmorpholine-N-oxide.
- Tang, Li-Hua,Wu, Fule,Lin, Hui,Jia, Ai-Quan,Zhang, Qian-Feng
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p. 212 - 218
(2018/04/02)
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- Oxidation of Alcohols to Carbonyl Compounds Catalyzed by Oxo-Bridged Dinuclear Cerium Complexes with Pentadentate Schiff-Base Ligands under a Dioxygen Atmosphere
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Ionic mononuclear and neutral dinuclear complexes of cerium(III) 3-L1-3-L9 bearing a series of dianionic pentadentate Schiff-base ligands were synthesized, characterized, and used as catalysts for N-oxyl radical-free aerobic alcohol oxidation. Reactions of Ce(NO3)3·6H2O with o-tert-butyl-substituted sterically hindered ligands NH(CH2CH2-Rfnet=CHC6H2-3-(tBu)-5-R2-2-OH)2 (for L1H2, R2 = tBu; for L2H2, R2 = OMe; and for L3H2, R2 = H) in the presence of triethylamine afforded the corresponding anionic cerium complexes [HNEt3][Ce(L1-3)(NO3)2] (3-L1-3-L3), whereas complexation with sterically less hindered ligands, such as NH(CH2CH2N=CHC6H2-3-R1-5-R2-2-OH)2 (for L4H2, R1 = OMe and R2 = H; for L5H2, R1 = H and R2 = tBu; for L6H2, R1 = H and R2 = OMe; for L7H2, R1 = H and R2 = H; for L8H2, R1 = H and R2 = NO2; and for L9H2, R1 = tBu and R2 = NO2), afforded neutral dinuclear complexes [Ce(L4-9)(NO3)]2 (3-L4-3-L9). Among these newly prepared complexes, complex 3-L1 was selected as the best catalyst for oxidizing primary and secondary alcohols under a dioxygen atmosphere without any N-oxyl radicals such as TEMPO to produce the corresponding carbonyl compounds, where the oxo-bridged dinuclear complex worked as a catalyst while maintaining its dinuclear skeleton during the catalytic cycle. In addition, an intramolecular redox process between the two cerium centers through the bridging oxygen atom played a key role in forming the ligand phenoxide radical-mediated TEMPO-free alcohol oxidation reaction.
- Shirase, Satoru,Shinohara, Koichi,Tsurugi, Hayato,Mashima, Kazushi
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p. 6939 - 6947
(2018/06/25)
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- Synthesis of some ketones via nano-nickel oxide catalyzed acylation of arylzinc reagents; strategy involving the use of mixed (methyl)(aryl)zincs
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Nano-NiO catalyzed acylation of mixed (methyl)(aryl)zincs with aromatic acyl halides in THF at room temperature provides a new facile route for aryl–aroyl coupling. Among NiCl2 .L2 and NiCl2 .L (L = monodentate and bidentate phosphine ligand) catalysts, the lower catalyst loading of NiCl2 (dppf) may seem attractive; however, nano-NiO, being the lowest cost catalyst, is more favorable for aroylation of (methyl)(aryl)zincs. This procedure also provides a supplement to Cu and Pd catalyzed acylation of diorganozincs.
- Pekel, ?zgen ?MüR,Erdik, Ender,Kalkan, Melike
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p. 759 - 767
(2018/06/07)
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- Highly efficient synthesis of aryl ketones by PEPPSI-palladium catalyzed acylative Suzuki coupling of amides with diarylborinic acids
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An improved acylative cross-coupling of various N-methyl-N-tosyl amides with diarylborinic acids for synthesis of aryl ketones is developed. In most cases, aryl ketones could be obtained in excellent yields by using 1 mol% 2,6-diisopropylphenylimidazolylidene and 3-chloropyridine co-supported palladium chloride as catalyst in the presence of 3 equiv. K2CO3 as base in refluxing THF. The readily prepared and cost-effective substrates, N-methyl-N-tosylamides and diarylborinic acids, and the commercially available catalyst system promise a practical and efficient access to aryl ketones.
- Wang, Chen,Huang, Lingyun,Wang, Fengze,Zou, Gang
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p. 2299 - 2301
(2018/05/16)
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- Method for removing oxime through catalysis of tellurium
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The invention provides a method for removing oxime through catalysis of tellurium and relates to the technical field of oxime removal. According to the method provided by the invention, commercializeddiphenyl ditelluride ether is used as a catalyst; oxygen gas is used as an oxidant under a solvent-free condition and oxime is heated so that oxime can be removed to obtain a carbonyl compound; the catalyst also can be repeatedly utilized. The method is clean and environmentally friendly, low in cost and safe to operate, so that the method is an effective oxime removing method. According to the method provided by the invention, raw materials are selected from various aryl or alkyl substituted oxime. According to the method provided by the invention, reaction does not need a solvent so that the reaction cost can be reduced and a process is clean and environmentally friendly. The oxidant provided by the invention is the oxygen gas and can be used for sufficiently oxidizing a substrate, andthe yield is the highest.
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Paragraph 0014; 0023; 0024
(2018/07/15)
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- Palladium-Catalyzed Carbonylative Homocoupling of Aryl Iodides for the Synthesis of Symmetrical Diaryl Ketones with Formic Acid
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A convenient method for the palladium-catalyzed carbonylative homocoupling of aryl iodides was developed. With formic acid as the CO source, various symmetrical diaryl ketones were synthesized in moderate to good yield in the presence of a palladium catalyst.
- Wu, Fu-Peng,Peng, Jin-Bao,Qi, Xinxin,Wu, Xiao-Feng
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p. 173 - 177
(2017/11/27)
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- Pd-NHC catalysed Carbonylative Suzuki coupling reaction and its application towards the synthesis of biologically active 3-aroylquinolin-4 (1H)-one and acridone scaffolds
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We have unfolded a convenient and mild protocol for the synthesis of diaryl ketones via Pd- NHC catalysed carbonylative Suzuki coupling reaction. Notably, this method offers advantages like no use of toxic CO gas, shorter reaction time, high yield, and broad substrate scope. Several sensitive functional groups (like-COMe, -COOMe, -F, -Cl, -Br, -NH2, -CN) are well tolerated in this reaction. In addition, we have also demonstrated a new efficient route for the synthesis of biologically active and pharmaceutically important 2-substituted 3-Aroylquinolin-4(1H)-ones and acridone scaffolds.
- Ghosh, Prasanjit,Ganguly, Bhaskar,Das, Sajal
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- Nickel-Catalyzed Molybdenum-Promoted Carbonylative Synthesis of Benzophenones
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A nickel-catalyzed molybdenum-promoted carbonylative coupling reaction for the synthesis of benzophenones from aryl iodides has been developed. Various substituted diaryl ketones were synthesized in moderate to excellent yields under CO-gas-free conditions. A synergetic effect of both nickel and molybdenum has been observed, which is also responsible for the success of this transformation.
- Peng, Jin-Bao,Wu, Fu-Peng,Li, Da,Qi, Xinxin,Ying, Jun,Wu, Xiao-Feng
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p. 6788 - 6792
(2018/06/04)
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- Chloramine-T-mediated oxidation of benzylic alcohols using indium(III) triflate
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The efficient oxidation of benzylic alcohols to carbonyl compounds was performed using chloramine-T and a catalytic amount of indium(III) triflate. The primary benzylic alcohols were converted to the corresponding aldehydes in a good yield, and the secondary benzylic alcohols were oxidized to ketones in a high yield. The optimized reaction conditions required 0.3eq of indium(III) triflate and the use of acetonitrile as a solvent.
- Nakahara, Kazuhide,Kitazawa, Chie,Mineno, Tomoko
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p. 801 - 804
(2017/08/09)
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- T-BuONa-Mediated Transition-Metal-Free Autoxidation of Diarylmethanes to Ketones
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Autoxidative sp3 C-H transformation of diarylmethanes has been demonstrated using O2-mediation by t-BuONa. This protocol enables an alternative route for the access to diaryl ketones from benzyl derivatives in good to excellent yields under mild reaction conditions, without transition metal catalysts or additional chemical oxidants.
- Li, Jiang-Sheng,Yang, Fan,Yang, Qian,Li, Zhi-Wei,Chen, Guo-Qin,Da, Yu-Dong,Huang, Peng-Mian,Chen, Chao,Zhang, Yuefei,Huang, Ling-Zhi
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supporting information
p. 994 - 998
(2017/05/10)
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- Base free Suzuki acylation reactions of sodium (aryl trihydroxyborate) salts: A novel synthesis of substituted aryl ketones
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The first simple and efficient base free Pd(PPh3)4 catalysed synthesis of substituted aryl ketones from acyl chlorides and easily accessible sodium aryl trihydroxyborate salts in aqueous toluene is reported. The reaction conditions appeared versatile and tolerable to a variety of functional groups including, CF3, OMe, SMe, Br, NO2, F, OH and NH2 furnishing 25 examples of substituted aryl ketones in isolated yields of up to 96% in 24 h. Beside the high purity, the ease and convenience of the isolation compared to boronic acids, sodium aryl trihydroxyborate salts could be used subsequently without the addition of excess amount of an activator and are more user-friendly in terms of the use of accurate reaction stoichiometry.
- Sithebe, Siphamandla,Molefe, Patience
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p. 305 - 311
(2017/07/13)
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- A gassing of methyl tertiary method (by machine translation)
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The invention provides a simple synthesis of plants the alkone. The method in the solvent and dehydrating agent under the condition, in order to ceric nitrate as the catalyst, the oxidation oxygen medicinal preparation α - methyl tertiary alcohol, generating carbonyl compound. Compared with the traditional method, this method has the advantages of simple economic, environmental protection, high yield, mild reaction conditions, does not use any ligand, low catalyst consumption, substrate and wide application range, the synthesis of such compounds is simple synthesis method. (by machine translation)
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Paragraph 0015; 0016; 0017; 0018; 0019; 0020; 0021-0047
(2017/08/24)
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- At normal pressure fragrant ketone copper catalytic synthesis method
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The invention discloses a method of synthesizing diaryl ketone under normal pressure by virtue of copper catalysis. The method is as follows: in a solvent alcohol or aqueous liquor of alcohol, under action of alkali and acid, adding a copper catalyst, alkyl iodide, alkyl boric acid and carbon monoxide to directly carry out crossed coupling reaction to prepare diaryl ketone compounds. According to the invention, the method of preparing diaryl ketone compounds by carbonylation Suzuki coupling reaction has the advantages as follows: the catalyst is wide in source, cheap and small in toxicity; the reaction is free of ligand in reaction and good in activity; the reaction is carried out under the normal pressure and selectivity is high; a substrate source is wide and stable; functional group compatibility is good and scope of application for the substrate is wide; a reaction medium is environment-friendly and recyclable. Under the condition of optimizing reaction conditions, the target product separating yield is 95%.
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Paragraph 0032; 0033; 0038
(2017/07/14)
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- A gassing by olefin method
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The invention provides a simple synthetic method for synthesizing a ketone from an olefin, and relates to the field of the synthetic technology of carbonyl compounds. The method includes the step that ceric ammonium nitrate serves as a catalyst, oxygen serves as an oxidizing agent, and the disubstituted terminal olefin is subjected to catalytic oxidation to prepare the carbonyl compound. Compared with a traditional method, the method is environmentally friendly and high in yield, reaction conditions are moderate, no ligand is used, the usage amount of the catalyst is small, a substrate is wide in application range, and the method is the simple synthetic method for synthesizing ketones.
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Paragraph 0016; 0037-0041
(2017/07/06)
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