- Suzuki-Miyaura coupling under air in water promoted by polymer supported palladium nanoparticles
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Suzuki couplings of aryl bromides were efficiently performed by a polymer supported palladium catalyst under air in water at 100°C without additives. In the case of activated aryl chlorides the reactions proceeded smoothly in the presence of a suitable phase transfer agent. The catalyst was active and recyclable for at least five times. Atomic absorption analyses revealed that the metal content in the polymeric support did not significantly decrease with the cycles while inductively coupled plasma analyses revealed that the palladium amount both in the mother liquors and in the organic products after reactions was lower than 500 ppb. The activity of the mother liquors has been investigated in detail. A transmission electron microscopy study of the supported catalyst before, during and after duty is also described.
- Dell'Anna, Maria Michela,Mali, Matilda,Mastrorilli, Piero,Rizzuti, Antonino,Ponzoni, Chiara,Leonelli, Cristina
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- Substituent effects on indirect carbon-carbon couplings, J(CC), in substituted thiophenes, pyrroles, and furans studied by experiment and theory
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An excellent linear correlation is found between a large set of experimental spin-spin carbon-carbon coupling constants, J(CC), in thiophene, pyrrole, and furan systems and the corresponding B3PW91/6-311++G(2d,p)//B3PW91/ 6-311++G(2d,p) calculated estimates. The correlation does not differ significantly from the simplest relationship possible, J(CC)exp. = J(CC)calcd., within a small and random spread of about 1 Hz. There are 285 experimental values considered, and 202 out of these are new and come from the present work. The character of the correlation indicates that rovibronic effects on aromatic J(CC)'s, and those of nuclear motions on aromatic J(CC)'s are practically negligible. All of this is in a perfect agreement with our recent extensive studies on aromatic J(CC)'s in pyridine and benzene ring systems. As has been shown by computations, not only large one-bond couplings but also almost all long-range ones occurring between the carbons of the heteroaromatic rings are, with a few exceptions, positive. Significant substituent effects experimentally observed in the one-bond as well as long-range couplings are very accurately reproduced by the computation. The experimental coupling magnitudes vary from ca. 1 to 98 Hz. The J(CC)'s computed for the model variously substituted trimethylsilyl and fluoro derivatives, which are not easily accessible experimentally, span a range of about 130 Hz, from ca. -2 in up to ca. +125 Hz. Copyright
- Kamienska-Trela, Krystyna,Dvornikova, Elena,Biedrzycka, Zenobia,Witanowski, Michal
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- Structure and Internal Rotation in 3-Phenylthiophene Using NMR Spectra of Liquid-Crystalline Solutions
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The NMR spectra of 3-phenylthiophene as solute in liquid-crystal solvents were analyzed and the direct couplings constants, Dij obtained were used to test different models of the potential energy function V(φ) for intramolecular rotation of the phenyl and thiophene units.The data are consistent with a V(φ) having a minimum at about 24 deg.The LCNMR technique is highly discriminant among different models of V(φ) provided that enough Dij couplings are available.Ab initio calculations are also reported.
- Chidichimo, Giuseppe,Liguori, Angelo,Longeri, Marcello,Veracini, Carlo Alberto
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- Fabrication of hollow palladium spheres and their successful application to the recyclable heterogeneous catalyst for suzuki coupling reactions
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Novel palladium hollow spheres were synthesized using silica spheres as a template, and they were successfully applied as recyclable heterogeneous catalysts for Suzuki cross coupling reactions. Copyright
- Kim, Sang-Wook,Kim, Minsuk,Lee, Wha Young,Hyeon, Taeghwan
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- A C3v-symmetric triphosphine ligand derived from trindane skeleton: synthesis, inclusion of C60, and catalytic activity of its Pd complex
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With the aim to design a multidentate C3v-symmetric trindane-based trisphosphine ligand 3 for Suzuki-Miyaura cross-coupling of 3-bromothiophene with phenylboronic acid, we observed the ability of this ligand to form an inclusion complex with buckyball C60. Along with its catalytic activity, the pyramidal inversion at phosphorous atoms of 3 and the formation of 3@C60 were investigated by 1H NMR, 31P{1H} NMR and DFT methods.
- Lim, Dong Seob,Sahoo, Suban K.,Cho, Chan Sik,Kim, Yang,Choi, Heung-Jin
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- Electrochemical Preparation of Highly Anode-active Poly(3-phenylthiophene)
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The electrochemical preparation of poly(3-phenylthiophene) is described; when doped with cations as well as anions, it exhibits interesting spectroscopic properties.
- Sato, Masa-aki,Tanaka, Susumu,Kaeriyama, Kyoji
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- Organocatalytic synthesis of (Het)biaryl scaffoldsviaphotoinduced intra/intermolecular C(sp2)-H arylation by 2-pyridone derivatives
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A uniqueN,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcasedviathe construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
- Das, Tapas Kumar,Kundu, Mrinalkanti,Mondal, Biswajit,Ghosh, Prasanjit,Das, Sajal
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p. 208 - 218
(2021/12/29)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0093-0101
(2021/02/24)
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- Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
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The photoelectric properties and catalytic activities of substituted triphenylphosphine and sulfur/selenium ligand supported aromatic triangular tri-palladium complexes1-4, abbreviated as [Pd3]+, were investigated. The cyclic voltammogram of [Pd3]+in CH3CN-nBu4NPF6showed a single quasi-reversible wave which was consistent with their robust property and provided preliminary proof for their electron transfer processes in catalysis. With excitation at 267 nm, [Pd3]+exhibited strong ratiometric fluorescence at 550 and 780 nm at a temperature gradient from 77 K to 287 K. These peculiar triangular tri-palladium complexes showed excellent catalytic activities and exclusive reactivity with aryl iodides over the other halogenated aromatics in the Suzuki-Miyaura coupling reaction. The electronic and steric hindrance effects of substituents on the aryl iodides and aryl boronic acids including heteroaromatics like pyridine, pyrazine and thiophenes were explored and most substrates achieved up to 99% of yields. (2-[1,1′-Biphenyl]-2-ylbenzothiazole) which was analogous to the selective cyclooxygenase-2 (COX-2) inhibitors was also synthesized with our tri-palladium catalyst and gave good isolated yield (94%). The study of the catalytic process revealed that the mechanism of the reaction may involve the replacement of the sulphur ligand on [Pd3]+by iodine from aryl iodides, which was beneficial for the matching of C-I bond energy.
- Li, Jia,Li, Xujun,Liu, Xiang,Maestri, Giovanni,Malacria, Max,Wang, Xiaoshuang,Wang, Yanlan,Wu, Lingang
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supporting information
p. 11834 - 11842
(2021/09/06)
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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- Cap-dependent endonuclease inhibitors
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The present invention provides a compound of formula (I) for inhibiting influenza virus replication. A pharmaceutically acceptable salt, metabolite, or prodrug thereof. The compounds can be used for preparing medicaments for treating influenza. The invention further discloses a method and for preparing the same, and a composition comprising the compound and a pharmaceutically acceptable carrier.
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Paragraph 0330; 0343-0346
(2021/11/10)
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- 2-AMINO-N-(AMINO-OXO-ARYL-LAMBDA6-SULFANYLIDENE)ACETAMIDE COMPOUNDS AND THEIR THERAPEUTIC USE
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The present invention pertains generally to the field of therapeutic compounds. More specifically the present invention pertains to certain 2-amino-N-(amino-oxo-aryl-λ6- sulfanylidene)acetamide compounds (referred to herein as ANASIA compounds) that, inter alia, inhibit (e.g., selectively inhibit) bacterial aminoacyl-tRNA synthetase (aaRS) (e.g., bacterial leucyl-tRNA synthetase, LeuRS). The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, to inhibit (e.g., selectively inhibit) bacterial aminoacyl-tRNA synthetase; to treat disorders that are ameliorated by the inhibition (e.g., selective inhibition) of bacterial aminoacyl-tRNA synthetase; to treat bacterial infections; etc.
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Page/Page column 235
(2021/06/26)
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- 2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
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We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
- Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 1560 - 1564
(2021/05/29)
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- Anchored PdCl2 on fish scale: an efficient and recyclable catalyst for Suzuki coupling reaction in aqueous media
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PdCl2 anchored on fish scale (FS) complex were intended to a heterogeneous catalyst for ligand-free Suzuki coupling reaction in aqueous media. The catalyst FS-PdCl2 was characterized by FT-IR, powder XRD, XPS and SEM. FS-PdCl2 complex has been successfully implemented for Suzuki coupling reactions of various halogenated aromatics with arylboronic acid to provide the corresponding biaryl compounds under environmentally friendly conditions (40 °C, water solvent). Moreover, the efficient catalyst shows excellent stability and recyclability, and its catalytic activity without any decrease after 8 times consecutive reused.
- Yang, Quanlu,Yang, Fawang,Zhang, Ying,Hou, Juanjuan,Li, Jiankun,Cheng, Jinkui,Wu, Shang,Zhan, Huiying,Zhang, Xinghui,Shi, Haixiong
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supporting information
(2020/12/25)
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- Sterically controlled C-H alkenylation of pyrroles and thiophenes
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Pd-catalyzed C-H alkenylations targeting the least hindered position of N-alkyl pyrroles and 3-substituted thiophenes, as opposed to electronically controlled approaches, are developed. The steric demand and stable bidentate binding mode of the pyrazolonaphthyridine ligand are key to the success of these sterically controlled alkenylations using oxygen as an oxidant.
- Jeon, Ju Eun,Jeong, Siyeon,Joo, Jung Min,Kang, Eunsu,Kim, Hyun Tae
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supporting information
p. 11791 - 11794
(2021/11/30)
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- Lipids as versatile solvents for chemical synthesis
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Development of safe, renewable, cheap and versatile solvents is a longstanding challenge in chemistry. We show here that vegetable oils and related systems can become prominent solvents for organic synthesis. Suzuki-Miyaura, Hiyama, Stille, Sonogashira and Heck cross-couplings proceed with quantitative yields in a range of vegetable oils, fish oil, butter and waxes used as solvents. Appropriate methodologies for high-throughput screening and sustainable isolation techniques applicable for vegetable oils and related lipids are presented.
- Bayer, Annette,Gevorgyan, Ashot,Hopmann, Kathrin H.
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supporting information
p. 7219 - 7227
(2021/09/28)
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- Redox-Divergent Construction of (Dihydro)thiophenes with DMSO
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Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.
- Chen, Qing-An,He, Gu-Cheng,Hu, Yan-Cheng,Ji, Ding-Wei,Liu, Heng,Zhang, Xiang-Xin,Zhao, Chao-Yang
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supporting information
p. 24284 - 24291
(2021/10/08)
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- Pd-NHCs Enabled Suzuki-Miyaura Cross-Coupling of Arylhydrazines via C–N Bond Cleavage
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We describe a highly efficient protocol for cross-coupling of phenylhydrazines with arylboronic acids by Pd-NHCs under aerobic reaction condition. A series of well-defined Pd-NHCs complexes were evaluated and the relationship between the structure and the catalytic properties was investigated. It was disclosed that the Pd-PEPPSI-IPr proved to be the robust precatalyst, providing access to a range of (hetero)biaryls in good to excellent yields.
- Zeng, Xiao-Xiao,Li, Dong-Hui,Zhou, Zhen,Xu, Chang,Liu, Feng-Shou
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supporting information
(2021/03/01)
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- Small organic molecules with tailored structures: Initiators in the transition-metal-free C-H arylation of unactivated arenes
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Simple, small organic molecules containing nitrogen and oxygen atoms in their structures have been disclosed to catalyze transition-metal-free C-H arylation of unactivated arenes with aryl iodides in the presence of tBuOK. In this article, an optimized catalytically active molecule, (2-(methylamino)phenyl)methanol, was designed. A broad range of aryl iodides could be converted into the corresponding arylated products at 100 °C over 24 h with good to excellent yields. Mechanistic experiments verified that radicals participated in this catalytic transformation and that the cleavage of the aromatic C-H bond was not the rate determining step. A K+ capture experiment by 18-crown-6 emphasized the significance of the cation species of the strong base. Fourier transform infrared spectroscopy proved that the catalytic system was activated by the hydrogen bonds between small organic molecules and tBuOK. Also, a clear mechanism was proposed. This transition-metal-free method affords a promising system for efficient and inexpensive synthesis of biaryls via a user-friendly approach, as confirmed by scale-up experiments.
- Chen, Suqing,Chen, Wenjun,Chen, Yu,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong
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p. 14500 - 14509
(2020/04/27)
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- Organocatalyst in Direct C(sp2)-H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed Inter-/Intra-molecular C-H Bond Activation
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This article describes the identification of 1-(2-hydroxyethyl)-piperazine as a new, cost-effective, highly efficient organocatalyst, which promotes both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C-H arylation of unactivated benzenes with aryl halides (Ar-X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol percent organocatalyst, the intra-molecular C-H arylation catalytic system composed of 40 mol percent each of the catalyst and the additive (4-dimethylaminopyridine (DMAP)). The novel catalyst was also able to perform both inter- A nd intra-molecular direct arylations simultaneously in a single pot. The mechanistic studies confirmed the involvement of aryl radical anions and proceeded via a single-electron-transfer (SET) mechanism. The large substrate scope, high functional group tolerance, competition experiments, gram-scale synthesis, and kinetic studies further highlight the importance and versatile nature of the methodology as well as the compatibility of the new catalyst. To the best of our knowledge, this is the first report on any organocatalyst that reported detailed investigations of both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in a single representation.
- Yadav, Lalit,Tiwari, Mohit K.,Shyamlal, Bharti Rajesh Kumar,Chaudhary, Sandeep
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p. 8121 - 8141
(2020/07/16)
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- INFLUENZA VIRUS REPLICATION INHIBITOR AND USE THEREOF
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Disclosed are a compound as shown in formula (I) as an influenza virus replication inhibitor and a preparation method therefor, a pharmaceutical composition comprising the compound and the use of the compound and pharmaceutical composition thereof in the treatment of influenza.
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Paragraph 0233; 0242; 0291-0292
(2020/08/09)
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- Synthesis of water soluble Pd-Piperidoimidazolin-2-ylidene complexes and their catalytic activities in neat water
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Through the strategy of water soluble N-heterocyclic carbene (NHC) ligand, Pd-catalyzed reactions were developed in aqueous media. Therefore, four new piperidoimidazolinium salts (1a-d) consisting of sulfonate (a), esther (b, c) and carboxylic acid (d) functionalities and their water-soluble Pd-NHC complexes (2a-d) were synthesized. The new compounds were characterized by elemental analysis, FTIR, TGA, UV–vis and NMR spectroscopy. The catalytic activities of water soluble Pd-NHC complexes (2a-d) were investigated using the Suzuki-Miyaura (S-M) reaction and the reduction of nitroarenes. We found that the water-soluble polar or ionic groups on piperidoimidazolin-2-ylidine had an effect on the catalytic activity. The water-soluble catalyst can be recycled efficiently and reused six times with only a very slight loss of catalytic activity.
- ?ak?r, Sinem,Türkmen, Hayati
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- A new approach to large scale production of dimethyl sulfone: A promising and strong recyclable solvent for ligand-free Cu-catalyzed C-C cross-coupling reactions
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Dimethyl sulfone (DMSN) was easily prepared through efficient oxidation of dimethyl sulfoxide (DMSO) and used as a strong and green solvent for organic reactions. A mixture of HNO3/NaOCl was used as an oxidizing agent for efficient oxidation of DMSO to DMSN. The effect of DMSN was evaluated for copper-catalyzed coupling reactions. It is worth noting that DMSN could play the role of a ligand for copper ions. A general survey was accomplished for various types of C-C cross-coupling reactions catalyzed by CuI in DMSN in the absence of any ligand. Moderate to good yields were achieved for Sonogashira, Heck, and Suzuki cross-coupling reactions. Finally, DMSN was recovered and reused for several consecutive runs without any loss of its activity.
- Cheng, Shen,Wei, Wei,Zhang, Xingyu,Yu, Hewei,Huang, Mingming,Kazemnejadi, Milad
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p. 2069 - 2076
(2020/04/07)
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- Decarbonylative Suzuki-Miyaura Cross-Coupling of Aroyl Chlorides
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Herein, we report a catalyst system for Pd-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of aroyl chlorides with boronic acids to furnish biaryls. This strategy is suitable for a broad range of common aroyl chlorides and boronic acids. The synthetic utility is highlighted in the direct late-stage functionalization of pharmaceuticals and natural products capitalizing on the presence of carboxylic acid moiety. Extensive mechanistic and DFT studies provide key insight into the reaction mechanism and high decarbonylative cross-coupling selectivity.
- Zhou, Tongliang,Xie, Pei-Pei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 6434 - 6440
(2020/09/02)
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- The Synthesis and Catalytic Activity of New Mixed NHC-Phosphite Nickel(0) Complexes
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Herein we describe the synthesis and isolation of the first low-valent NHC-phosphite nickel complexes of general formula Ni(NHC)[P(OAr)3]2. These three-coordinate Ni(0) compounds were fully characterized, including by X-ray crystallography that highlighted their trigonal planar geometry. The representative complex Ni(IMes)[P(OPh)3]2 was used to show that a phosphite ligand is readily substituted in the presence of an aldehyde or nitrile. These stoichiometric studies then led to an investigation of their catalytic properties in the Suzuki-Miyaura cross-coupling reactions between aryl tosylates and aryl boronic acids, a first for such a NHC-Ni catalyst. Finally, mechanistic investigations led to the isolation of a well-defined oxidative addition product.
- Dorta, Reto,Duczynski, Jeremy,Moggach, Stephen A.,Sobolev, Alexandre N.,Stewart, Scott G.
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supporting information
(2020/01/21)
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- Method for preparing biaryl from aryl sulfonyl hydrazide
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The invention discloses a method for preparing biaryl from aryl sulfonyl hydrazide, which comprises the following steps: under the action of palladium catalyst, ligand and base, allowing aryl sulfonylhydrazide and brominated aromatic hydrocarbon undergo coupling reaction, and after the reaction is finished, obtaining the biaryl compound through post-treatment. The reaction conditions are mild andthe functional groups are well tolerated, so the method has a wide range of substrate applicability.
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Paragraph 0039-0043
(2019/10/17)
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- Visible-Light-Induced [4+2] Annulation of Thiophenes and Alkynes to Construct Benzene Rings
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The [4+2] annulation represents an elegant and versatile synthetic protocol for the construction of benzene rings. Herein, a strategy for visible-light induced [4+2] annulation of thiophenes and alkynes, to afford benzene rings, is presented. Under simple and mild reaction conditions, the ready availability and structural diversity of thiophenes and alkynes permit the facile synthesis of several substituted aromatic rings. Valuable drugs and amino acids are also well tolerated. Moreover, DFT calculations explain the high regioselectivity of the reaction.
- Song, Chunlan,Dong, Xin,Wang, Zhongjie,Liu, Kun,Chiang, Chien-Wei,Lei, Aiwen
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supporting information
p. 12206 - 12210
(2019/07/31)
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- Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
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Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
- Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 5736 - 5742
(2019/06/18)
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- Synthesis of heterobiaryls via Suzuki-Miyaura coupling reaction of potassium aryltrifluoroborates with heteroaryl halides in aqueous systems
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A variety of heterobiaryl compounds have been synthesized by the Suzuki-Miyaura coupling reactions of heteroaryl halides with potassium aryltrifluoroborates. Pd (OAc)2 was found to be highly efficient for the Suzuki-Miyaura coupling reactions of various heteroaryl halides with potassium aryltrifluoroborates in aqueous systems, delivering the corresponding heterobiaryl compounds in good to excellent yields.
- Liu, Leifang,Zhao, Kai,Li, Wenbo,Liu, Mingli,Chen, Yuting,Dong, Yan
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- Ni: Vs. Pd in Suzuki-Miyaura sp2-sp2 cross-coupling: A head-to-head study in a comparable precatalyst/ligand system
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The Suzuki-Miyaura reaction is a cornerstone method for sp2-sp2 cross-coupling in industry. There has been a concerted effort to enable the use of Ni catalysis as an alternative to Pd in order to mitigate cost and improve sustainability. Despite significant advances, ligand development for Ni-catalyzed Suzuki-Miyaura cross-coupling remains underdeveloped when compared to Pd and, as a consequence, ligands for Ni-catalyzed processes are typically taken from the Pd arena. In this study we evaluate the effect of using a similar Ni and Pd precatalyst based on a common bidentate ligand (dppf) in a head-to-head format for the most common type of biaryl couplings, establishing the practical implications of direct replacement of Pd with Ni, and identifying the potential origins of these observations in a mechanistic context.
- West, Matthew J.,Watson, Allan J. B.
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supporting information
p. 5055 - 5059
(2019/06/03)
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- Ligand-free Suzuki-Miyaura coupling reaction of an aryl chloride using a continuous irradiation type microwave and a palladium nanoparticle catalyst: Effect of a co-existing solid
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We have explored the effect of a co-existing metal in the ligand-free Suzuki-Miyaura coupling reaction of an aryl chloride, which is promoted by a "continuous irradiation type microwave" and a "palladium nanoparticle catalyst", and found that the co-existing metal affects this reaction due to its absorption ability of microwave energy in the reaction system. We also observed that spiking occurred more frequently in the presence of a co-existing metal.
- Yamada, Makito,Shio, Yasunori,Akiyama, Toshiki,Honma, Tetsuo,Ohki, Yuuta,Takahashi, Naoyuki,Murai, Kenichi,Arisawa, Mitsuhiro
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p. 4541 - 4549
(2019/08/21)
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- Thiazole-based non-symmetric NNC-palladium pincer complexes as catalytic precursors for the Suzuki-Miyaura C-C coupling
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We report an efficient synthesis of new non-symmetric pincer palladacycles 2a-i, containing a [NNC]-tridentate ligand formed by a hydrazone and a thiazolyl moiety as sources of N-donor atoms. These catalytic precursors were tested in the Suzuki-Miyaura cross coupling reaction using a variety of aryl boronic acids with aryl bromides or chlorides using water as solvent. Complex 2a displays the best catalytic performance under aerobic conditions, affording the coupling products in good to high yields. In all cases, the cross-coupling reaction was conducted under IR irradiation, allowing a decrease in the reaction time.
- Camacho-Espinoza, Martín,Reyes-Deloso, Alberto,Toscano, R. Alfredo,Penieres-Carrillo, J. Guillermo,López-Cortés, José G.,Ortega-Alfaro, M. Carmen,Ortega-Jiménez, Fernando
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p. 12967 - 12978
(2019/08/30)
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- An efficient and simple imidazole-hydrazone ligand for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions in water under infrared irradiation
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A highly efficient catalytic system based on Pd(OAc)2 and an imidazole-hydrazone ligand has been developed for Suzuki–Miyaura cross-coupling reaction in water under aerobic conditions using IR-irradiation. The system can tolerate a wide range of functionalized arylboronic acids and aryl halides. Furthermore, this protocol is also applicable for hetero-aryl bromides.
- Camacho-Espinoza, Martín,Penieres-Carrillo, José Guillermo,Rios-Guerra, Hulme,Lagunas-Rivera, Selene,Ortega-Jiménez, Fernando
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p. 386 - 391
(2019/01/03)
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- A Graphene Oxide Nanosheet Supported NHC-Palladium Complex as a Highly Efficient and Recyclable Suzuki Coupling Catalyst
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A practical heterogeneous catalyst was prepared by anchoring a triazine-tethered N-heterocyclic carbene (NHC)-palladium complex on the surface of graphene oxide (GO) nanosheets. The immobilized complex was characterized by X-ray photoelectron spectroscopy, field-emission transmission electron microscopy, energy-dispersive X-ray spectroscopy, and surface area analysis. It proved to be a highly active and durable heterogeneous catalyst for Suzuki coupling reactions. At room temperature, the use of this catalyst enabled the preparation of various biaryls and heterobiaryls in short reaction times. The catalytic system could be recycled at least 10 times with almost consistent activity. The results reveal that the stable palladium complex is strongly anchored on the surface of GO nanosheets. Interestingly, an open planar network of the GO nanosheet support plays a role during the catalytic process in enhancing the catalytic activity.
- Qian, Yingjie,So, Jaeil,Jung, Sang-Yung,Hwang, Sosan,Jin, Myung-Jong,Shim, Sang Eun
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p. 2287 - 2292
(2019/05/28)
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- Palladium-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of amides by carbon-nitrogen bond activation
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Palladium-catalyzed Suzuki-Miyaura cross-coupling or aryl halides is widely employed in the synthesis of many important molecules in synthetic chemistry, including pharmaceuticals, polymers and functional materials. Herein, we disclose the first palladium-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of amides for the synthesis of biaryls through the selective activation of the N-C(O) bond of amides. This new method relies on the precise sequence engineering of the catalytic cycle, wherein decarbonylation occurs prior to the transmetallation step. The reaction is compatible with a wide range of boronic acids and amides, providing valuable biaryls in high yields (>60 examples). DFT studies support a mechanism involving oxidative addition, decarbonylation and transmetallation and provide insight into high N-C(O) bond activation selectivity. Most crucially, the reaction establishes the use of palladium catalysis in the biaryl Suzuki-Miyaura cross-coupling of the amide bond and should enable the design of a wide variety of cross-coupling methods in which palladium rivals the traditional biaryl synthesis from aryl halides and pseudohalides.
- Zhou, Tongliang,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 9865 - 9871
(2019/11/11)
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- Cross-Coupling of Aryl Trifluoromethyl Sulfones with Arylboronates by Cooperative Palladium/Rhodium Catalysis
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The Suzuki-Miyaura arylation of aryl trifluoromethyl sulfones via C-SO2 bond cleavage has been developed by means of cooperative palladium/rhodium catalysis. A series of aryl trifluoromethyl sulfones and arylboronic acid neopentylglycol esters are converted to the corresponding biaryls. Mechanistic investigations suggest that (1) the rhodium catalyst mediates the transfer of the aryl ring from arylboronate to palladium, resulting in the acceleration of the transmetalation step, and (2) the C-C bond-forming reductive elimination step is the turnover-limiting step.
- Fukuda, Jun-Ichi,Nogi, Keisuke,Yorimitsu, Hideki
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supporting information
p. 8987 - 8991
(2019/11/11)
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- Desulfinative palladium-catalyzed cross-coupling of arylsulfonyl hydrazides with aryl bromides under air
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A highly efficient and mild palladium-catalyzed cross-coupling of arylsulfonyl hydrazides and aryl bromides for the selective synthesis of unsymmetrical biaryls has been developed. This methodology has the advantages of easily accessible starting materials, functional group tolerance and a wide range of substrates, which provide rapid access to biaryls derivatives. In this protocol, abundant and stable aryl bromides serve as the aryl sources by coupling reaction of the aryl group generated from arylsulfonyl hydrazides via in situ release of nitrogen and sulfur dioxide. No external oxidants or acids are needed for this kind of transformation.
- Liu, Qingling,Yang, Bo
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- Murahashi Cross-Coupling at ?78 °C: A One-Pot Procedure for Sequential C?C/C?C, C?C/C?N, and C?C/C?S Cross-Coupling of Bromo-Chloro-Arenes
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The coupling of organolithium reagents, including strongly hindered examples, at cryogenic temperatures (as low as ?78 °C) has been achieved with high-reactivity Pd-NHC catalysts. A temperature-dependent chemoselectivity trigger has been developed for the selective coupling of aryl bromides in the presence of chlorides. Building on this, a one-pot, sequential coupling strategy is presented for the rapid construction of advanced building blocks. Importantly, one-shot addition of alkyllithium compounds to Pd cross-coupling reactions has been achieved, eliminating the need for slow addition by syringe pump.
- Sinha, Narayan,Heijnen, Dorus,Feringa, Ben L.,Organ, Michael G.
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supporting information
p. 9180 - 9184
(2019/07/04)
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- Metal-Free Aerobic Oxidative Selective C-C Bond Cleavage in Heteroaryl-Containing Primary and Secondary Alcohols
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A transition-metal-free aerobic oxidative selective C-C bond-cleavage reaction in primary and secondary heteroaryl alcohols is reported. This reaction was highly efficient and tolerated various heteroaryl alcohols, generating a carboxylic acid derivative and a neutral heteroaromatic compound. Experimental studies combined with density functional theory calculations revealed the mechanism underlying the selective C-C bond cleavage. This strategy also provides an alternative simple approach to carboxylation reaction.
- Xia, Anjie,Qi, Xueyu,Mao, Xin,Wu, Xiaoai,Yang, Xin,Zhang, Rong,Xiang, Zhiyu,Lian, Zhong,Chen, Yingchun,Yang, Shengyong
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supporting information
(2019/05/07)
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- Accessing Heterobiaryls through Transition-Metal-Free C-H Functionalization
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Herein we report a transition-metal-free synthetic protocol for heterobiaryls, one of the most important pharmacophores in the modern drug industry, employing a new multidonor phenalenyl (PLY)-based ligand. The current procedure offers a wide substrate scope (24 examples) with a low catalyst loading resulting in an excellent product yield (up to 95%). The reaction mechanism involves a single electron transfer (SET) from a phenalenyl-based radical to generate a reactive heteroaryl radical. To establish the mechanism, we have isolated the catalytically active SET initiator, characterizing by a magnetic study.
- Banik, Ananya,Paira, Rupankar,Shaw, Bikash Kumar,Vijaykumar, Gonela,Mandal, Swadhin K.
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p. 3236 - 3244
(2018/03/23)
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- Urea-based organocatalyst catalyzed direct C–H bond arylations of unactivated arenes
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A simple 1,3-diethylurea was demonstrated to catalyze transition-metal-free arylations of unactivated aromatic C–H bonds with aryl iodides in the presence of t-BuOK. A broad range of aryl iodides with different arenes could couple in moderate to excellent yields. The mechanistic experiment results indicated that the radical is involved in this transformation.
- Zhao, Huaiqing,Xu, Xiangwen,Wu, Wei,Zhang, Wei,Zhang, Yunxian
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- Synthesis method of biaryl compounds
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The invention discloses a synthesis method of biaryl compounds. The method comprises the following step: enabling iodoaromatic compounds to react with aromatic hydrocarbon compounds in the presence ofa urea derivative catalyst and additives so as to obtain the biaryl compounds. According to the synthesis method of the biaryl compounds, all the steps are carried out in one reactor, and a separation step is not needed during synthesis, so that the reaction belongs to a one-pot reaction, the reaction yield is increased, and the reaction product is easy to purify. The synthesis method provided bythe invention uses a series of urea derivatives as the catalyst, and a single electron transfer process occurs between the catalyst and reactants so as to form free radicals, so that a C-C bond is further catalyzed to be formed, and biaryl is produced. Compared with the traditional transition metal catalysis method, the catalyst is cheap and easy to obtain, has good selectivity, high yield and strong applicability, and is easy to treat after the reaction is finished, so that the cost is lowered and the synthesis rate is increased.
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Paragraph 0097-0101
(2020/12/30)
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- Method for preparing bi-arene from aryl diazo salts and aryl sulfonylhydrazide
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The invention discloses a method for preparing bi-arene from aryl diazo salts and aryl sulfonylhydrazide. The method comprises the following steps of performing denitrification coupling reaction on aryl diazo salts and aryl sulfonylhydrazide in an organic solvent under the effects of palladium catalysts, ligands and additives; after the reaction is completed, performing post-treatment to obtain the bi-arene. The method provided by the invention has the advantages that the substrate price is low; the property is stable; the operation is convenient; meanwhile, the reaction yield is high; the substrate general applicability is high.
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Paragraph 0044; 0045; 0046
(2018/10/19)
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- Ligand-Free Bioinspired Suzuki–Miyaura Coupling Reactions using Aryltrifluoroborates as Effective Partners in Deep Eutectic Solvents
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Pd-catalyzed Suzuki–Miyaura cross-coupling between (hetero)aryl halides (Cl, Br, I) and versatile, moisture-stable mono- and bifunctional potassium aryltrifluoroborates proceeded efficiently and chemoselectively in air and under generally mild conditions; a catalyst loading as low as 1 mol % combined with Na2CO3 as a base in choline chloride/glycerol (1:2) deep eutectic solvent (DES) was used as a sustainable and environmentally responsible medium. The catalyst, base, and DES were easily and successfully recycled up to six times with an E-factor as low as 8.74. Valuable biaryls and terphenyl derivatives were furnished in yields of up to 98 %; over 50 reactions were compared and discussed. The methodology was applied for the synthesis of the nonsteroidal anti-inflammatory drugs Felbinac and Diflunisal.
- Dilauro, Giuseppe,García, Sergio Mata,Tagarelli, Donato,Vitale, Paola,Perna, Filippo M.,Capriati, Vito
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p. 3495 - 3501
(2018/09/21)
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- Suzuki–Miyaura coupling reaction in water in the presence of robust palladium immobilized on modified magnetic Fe3O4 nanoparticles as a recoverable catalyst
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Aryl halides and especially inactive aryl chlorides were coupled to benzenoid aromatic rings in a Suzuki–Miyaura coupling reaction in the absence of organic solvents and toxic phosphine ligands. The reaction was catalysed by a recoverable magnetic nanocatalyst, Pd@Fe3O4, in aqueous media. This method is green, and the catalyst is easily removed from the reaction media using an external magnetic field and can be re-used at least 10 times without any considerable loss in its activity. The catalyst was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, inductively coupled plasma spectroscopy, Fourier transform infrared spectroscopy, CHN analysis, X-ray diffraction and vibrating sample magnetometry.
- Dadras, Arefeh,Naimi-Jamal, M. Reza,Moghaddam, Firouz Matloubi,Ayati, Seyed Ebrahim
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- Sterically hindered N-aryl/benzyl substituted piperidoimidazolin-2-ylidene palladium complexes and their catalytic activities
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A series of N-aryl (2a,b) or benzyl (2c,d) substituted piperidoimidazolinium salts and their palladium complexes (3a-d) were prepared and characterized by 1H, 13C NMR, IR spectroscopy and elemental analysis. The crystal structures of 3a and 3c have been determined by X-ray crystallography. Thermogravimetric analysis (TGA) was applied to complexes (3a–d). The palladium complexes have been employed as catalyst for Suzuki-Miyaura cross coupling. The N-aryl substituted complex 3b was a highly efficient precatalyst and successfully employed in Suzuki-Miyaura cross coupling reactions of (hetero)aryl chlorides with arylboronic acids in air. In addition, the oxidative addition step of the reaction mechanism involving chlorobenzene and the catalysts 3a, 3b, 3c and 3d were computationally investigated by the DFT-ω-B97X-D method and complete agreement were obtained with the catalytic results. To measure σ-donating and π-acceptor properties of the new ligands, the rhodium carbonyl complexes were also prepared.
- Gacal, Elif,Denizalt?, Serpil,K?nal, Arma?an,G?k?e, Ayta? Gürhan,Türkmen, Hayati
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p. 6829 - 6838
(2018/10/20)
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- Thioether–NHC-Ligated PdII Complex for Crafting a Filtration-Free Magnetically Retrievable Catalyst for Suzuki–Miyaura Coupling in Water
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A new benzimidazolium salt, 1-[benzylaminocarbonylmethyl]-3-(2-phenylsulfanylethyl)-1H-benzimidazolium chloride (L), which is a precursor of a novel thioether-functionalized NHC, has been synthesized by subjecting 1H-benzimidazole to a sequence of reactions with 1,2-dichloroethane, sodium thiophenolate, and N-benzyl-2-chloroacetamide, successively. The moisture/air-insensitive complex [Pd(L–HCl)Cl2] (1) was prepared by the reaction of L with PdCl2. The molecular structure of 1, established by X-ray crystallography, revealed a square-planar geometry around Pd. Complex 1 was screened for Suzuki–Miyaura coupling reactions of various aryl/heteroaryl bromides (yields of up to 94 % in 2 h) in water at room temperature. Furthermore, complex 1 was immobilized onto the surface of aminopropyl-functionalized silica-coated magnetite nanoparticles [NPs, Fe3O4@SiO2-(CH2)3-NH2] by a stepwise modification strategy to develop the heterogeneous magnetically retrievable catalyst Fe3O4@SiO2-1′, in which the amide functionality present in the side-arm of the NHC within the NHC–PdII complex serves as linker. This magnetic nanosupport, bearing palladium complexes incorporating a novel thioether-based NHC ligand that functions in aqueous aerobic medium and can be easily separated, renders Fe3O4@SiO2-1′ a most desirable catalyst for the Suzuki–Miyaura coupling reaction. It was also observed that the catalyst was effective for up to seven cycles and was easily separated from the reaction medium by the use of an external magnet, further increasing its appeal.
- Nayan Sharma, Kamal,Satrawala, Naveen,Kumar Joshi, Raj
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p. 1743 - 1751
(2018/05/14)
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- N-heterocyclic carbene-Pd(II) complex based on theophylline supported on Fe3O4@SiO2 nanoparticles: Highly active, durable and magnetically separable catalyst for green Suzuki-Miyaura and Sonogashira-Hagihara coupling reactions
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In this paper, a novel heterogeneous palladium catalyst was synthesized by anchoring N-heterocyclic carbene-Pd(II) complex based on theophylline on magnetic Fe3O4@SiO2 nanoparticles. The synthesized magnetic composite was characterized by fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), vibration sample magnetometry (VSM), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), N2 adsorption-desorption isotherm analysis (BET), UV–vis spectroscopy and elemental analysis. Also, loading content of palladium on the catalyst was measured by inductive coupled plasma (ICP) analysis. The synthesized catalyst was used successfully for the Suzuki cross-coupling reactions of various aryl halides (I, Br, Cl) with phenylboronic acids. This reaction was best performed in water as a green solvent in the presence of just 0.37–0.5 mol% of the catalyst at 60 °C. Also, we have reported this recyclable catalytic system as a stable phosphine-free Pd catalyst for the Sonogashira cross-coupling of aryl halides (I, Br, Cl) with terminal aromatic and aliphatic alkynes under solvent-free conditions. All coupling reactions proceeded with good to excellent yields. The catalyst showed good stability and was recovered and reused for eight reaction cycles without a significant loss in its catalytic activity. Also, the leaching of the catalyst has been examined by a hot filtration test and ICP-AES analysis.
- Esmaeilpour, Mohsen,Sardarian, Ali Reza,Firouzabadi, Habib
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- Biological Evaluation and X-ray Co-crystal Structures of Cyclohexylpyrrolidine Ligands for Trypanothione Reductase, an Enzyme from the Redox Metabolism of Trypanosoma
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The tropical diseases human African trypanosomiasis, Chagas disease, and the various forms of leishmaniasis are caused by parasites of the family of trypanosomatids. These protozoa possess a unique redox metabolism based on trypanothione and trypanothione reductase (TR), making TR a promising drug target. We report the optimization of properties and potency of cyclohexylpyrrolidine inhibitors of TR by structure-based design. The best inhibitors were freely soluble and showed competitive inhibition constants (Ki) against Trypanosoma (T.) brucei TR and T. cruzi TR and in vitro activities (half-maximal inhibitory concentration, IC50) against these parasites in the low micromolar range, with high selectivity against human glutathione reductase. X-ray co-crystal structures confirmed the binding of the ligands to the hydrophobic wall of the “mepacrine binding site” with the new, solubility-providing vectors oriented toward the surface of the large active site.
- De Gasparo, Raoul,Brodbeck-Persch, Elke,Bryson, Steve,Hentzen, Nina B.,Kaiser, Marcel,Pai, Emil F.,Krauth-Siegel, R. Luise,Diederich, Fran?ois
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supporting information
p. 957 - 967
(2018/04/10)
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- Immobilization of palladium nanoparticles as a recyclable heterogeneous catalyst for the Suzuki–Miyaura coupling reaction
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This work describes the synthesis of Pd nanoparticles that are stabilized on CaAl-layered double hydroxide functionalized with Tris (tris(hydroxymethyl)aminomethane). The synthesized catalyst is characterized by several different analyses and has been successfully applied to the Suzuki–Miyaura reaction.
- Ghorbani-Vaghei, Ramin,Sarmast, Narges,Rahmatpour, Farid
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p. 644 - 651
(2018/04/19)
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- One-pot synthesis process for producing boron compounds
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The invention discloses a one-pot synthesis process for boron-amine compounds. The process comprises the steps of slowly dripping an anhydrous solvent, bromo-compounds RBr and XBY2 which are mixed into the anhydrous solvent containing metal lithium, maintaining the temperature at -20 to 20 DEG C in a dripping process, maintaining the temperature of -20 to 40 DEG C and reacting for 3-8h after the reaction initiation and the completion of adding the rest mixed solution, and separating to obtain the RBY2. An intermediate can be added with acid to be hydrolyzed to obtain organic boric acid, and reacted with diol to generate boric acid ester, or is directly conducted for coupled reaction with an aryl halogenate. The process is simple in process, few in by-product and high in reaction yield, and the ultralow temperature reaction and the dependency on the solvent by the stability of lithiated compounds can be prevented, therefore the process is applicable to industrial amplification and is beneficial for improving the core competitiveness of products.
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Paragraph 0039-0041
(2018/10/19)
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- Desulfinative and denitrogenative palladium-catalyzed cross-coupling of arylsulfonyl hydrazides with aryl diazonium salts
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Palladium-catalyzed cross-coupling of arylsulfonyl hydrazides with aryl diazonium salts to provide biaryl products under relatively mild conditions is established. This reaction proceeded smoothly with tetrabutylammonium iodide and gave the corresponding
- Shang, Yonghui
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- Air-Stable [(R3P)PdCl2]2 Complexes of Neopentylphosphines as Cross-Coupling Precatalysts: Catalytic Application and Mechanism of Catalyst Activation and Deactivation
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Air-stable [(R3P)PdCl2]2 complexes with di-tert-butylneopentylphosphine (DTBNpP, 1a) or trineopentylphosphine (TNpP, 1b) ligands have been applied to Suzuki cross-coupling reactions, and the mechanism of their conversion to the active LPd0 catalyst species has been studied. Precatalysts 1a,b provide effective catalysts for Suzuki cross-coupling of aryl bromides at room temperature, even when the reactions are performed in air. The precatalyst systems provided much higher activity catalysts in toluene/water in comparison to acetonitrile/water. Precatalyst loadings could be decreased by a factor of 50 in toluene in comparison to acetonitrile, while achieving equal or better yields. In acetonitrile/water, ligand metalation to form a [(κ2-P,C-DTBNpP)PdX]2 palladacycle was found to compete with formation of the active Pd(0) species. The palladacycle shows low catalytic activity; thus, its formation represents a catalyst deactivation pathway. In toluene, clean formation of the active Pd(0) species occurs without competitive palladacycle formation. The improved selectivity to form the active Pd(0) species in toluene appears to account for the higher activity of the precatalysts in toluene/water.
- Barnett, Kerry L.,Howard, James R.,Treager, Colin J.,Shipley, Adam T.,Stullich, Renee M.,Qu, Fengrui,Gerlach, Deidra L.,Shaughnessy, Kevin H.
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supporting information
p. 1410 - 1424
(2018/05/23)
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- Denitrogenative Pd/Cu-catalyzed Suzuki-type Cross-coupling of Aryltrifluoroborates with Arylhydrazine Hydrochlorides in Water under Room Temperature
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A water-soluble palladium-catalyzed Suzuki-type cross-coupling of aryltrifluoroborates with arylhydrazide hydrochlorides was efficiently developed under mild and environmentally benign conditions, in water without any ligand. The newly developed Pd/Cu co-catalyzed denitrogenative reaction gave a range of structurally diverse substituted biaryls with good to excellent yields, in which the byproduct was nitrogen.
- Wang, Guofang,Meng, Mengting,Deng, Liping,Cheng, Kai,Qi, Chenze
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- tert-butoxide-promoted coupling of aryl iodides with arenes using Di-tert-butyl hyponitrite as an initiator
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The coupling reaction of aryl iodides with arenes was found to proceed under mild conditions to give biaryls through a homolytic aromatic substitution mechanism, using potassium tert-butoxide and di-tert-butyl hyponitrite as a stoichiometric promoter and a radical initiator, respectively.
- Kiriyama, Kazuya,Shirakawa, Eiji
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supporting information
p. 1757 - 1759
(2017/11/23)
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