- A bimetallic complex containing a cyclopentadienyl-annulated imidazol-2-ylidene
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A bimetallic carbene complex architecture that incorporates a cyclopentadienyl-annulated imidazol-2-ylidene moiety is characterized. The ligand architecture enables direct electronic interaction between the π- and σ-bonded metals. A preliminary example of aqueous Suzuki coupling employing a metallocene-fused imidazol-2-ylidene-derived catalyst is described. Copyright
- Arduengo III, Anthony J.,Tapu, Daniela,Marshall, William J.
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- Novelty in Complexity: Relationship between Small Peptides, Pd Nanoparticles, and Catalyst Characteristics
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Bioinspired research: The Knecht group has recently developed specific peptide-capped Pd nanoparticle catalysts. The catalyst design, inspired by nature, and the complex approach with the use of varied characterization techniques is of great interest and offers new perspectives, as well as great opportunities, for the development of new catalyst materials for future sustainable developments
- Molnár, árpád
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- Peptide template effects for the synthesis and catalytic application of Pd nanoparticle networks
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Translation of nanomaterials from spherical to other shapes has demonstrated property and activity enhancement for applications ranging from optics to catalysis. Unfortunately, synthetic techniques for the controlled production of shaped nanomaterials, which can employ harsh conditions, remains challenging. In contrast, the fabrication of nanostructures using peptides has achieved the generation of functionally active materials using bio-conditions; however, these methods are typically limited to spherical materials. By merging these techniques, the biomimetic/ambient production of functional, shaped nanostructures may be achieved. Here we present the fabrication of non-spherical Pd nanostructures prepared using a peptide template. By controlling the Pd: peptide ratio, the production of at least three different Pd morphologies is possible: nanoparticles, short linear nanoribbons, and nanoparticle networks. Furthermore, all of the materials are active for Stille C-coupling catalysis using aqueous and room temperature conditions at low Pd concentrations. The results suggest that both the zerovalent Pd materials and the ligand surface structure modulate the reactivity, which may be exploitable for optimal functionality. The Royal Society of Chemistry 2010.
- Jakhmola, Anshuman,Bhandari, Rohit,Pacardo, Dennis B.,Knecht, Marc R.
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- Pronounced effect of pore dimension of silica support on Pd-catalyzed Suzuki coupling reaction under ambient conditions
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The pore size of the mesoporous silica support is found to have an enormous effect on the reactivity of the Pd-catalysts in the Suzuki coupling reaction. Heterogeneous palladium catalysts, MCM-Pd and SBA-Pd, have been synthesized using two different types of silica supports that differ from each other in their pore dimension. The silica surfaces are grafted with aminopropyl silane groups and functionalized with tris(4-formylphenyl)amine engaging one of the formyl groups while the other two formyl groups are reacted with two 2-aminothiophenol moieties. This results in two Schiff base sites with adjacent -SH groups leading to active metal binding sites in the samples and increases the hydrophobicity of the framework. The materials have been characterized by powder X-ray diffraction, nitrogen sorption studies, transmission electron microscopy, thermal analysis, and different spectroscopic techniques. The samples are used as catalysts for Suzuki cross-coupling reactions of aryl halides with phenylboronic acid under ambient conditions. The products of the reactions are identified and estimated by 1H NMR and gas chromatography. SBA-Pd performs much better compared to MCM-Pd and a yield of up to 98% is achieved in CH3OH within 24 h of the reactions. This is attributed to the higher pore dimension of SBA-Pd that allows better interaction of the substrate molecules with the active centers on the surface of the pores.
- Das, Trisha,Uyama, Hiroshi,Nandi, Mahasweta
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- Simple synthesis of sub-nanometer Pd clusters: High catalytic activity of Pd/PEG-PNIPAM in Suzuki reaction
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Ultra-small metal nanoclusters have high surface energy and abundant active sites, and therefore their catalytic activities are usually significantly higher than those of larger nanoparticles. A temperature-responsive copolymer, namely poly(ethylene glycol)-co-poly(N-isopropylacrylamide) (PEG-PNIPAM) was synthesized as the first step, and then ultra-small Pd clusters stabilized within PEG-PNIPAM copolymer micelles were formed by direct reduction. Pd nanoclusters of size less than 2 nm showed outstanding catalytic activity in the Suzuki coupling reaction. The reaction between iodobenzene and phenylboronic acid was completed in as little as 10 s (turnover frequency = 4.3 × 104 h?1). A yield of 64% was achieved in 5 min in the reaction between chlorobenzene and phenylboronic acid. The catalyst showed significant deactivation during three consecutive runs. However, this composite catalyst consisting of Pd/PEG-PNIPAM can be easily recycled based on the reversible phase transition of temperature-responsive PEG-PNIPAM. This catalyst therefore has good potential for practical applications.
- Chen, Zhe,Liang, Yu,Jia, Da-Shuang,Cui, Zhi-Min,Song, Wei-Guo
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- Photosensitizing properties of 2,4-dichlorobenzoic acid and chlorinated biphenyl carboxylic acids, potentially key components of chromophoric dissolved organic matter
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2,4-Dichlorobenzoic acid and a suite of models of chlorinated biphenyl carboxylic acids were found to be efficient sensitizers of the reactive oxygen species singlet oxygen (1O2). The Royal Society of Chemistry 2005.
- Boreen, Anne L.,McNeill, Kristopher
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- Exploiting localized surface binding effects to enhance the catalytic reactivity of peptide-capped nanoparticles
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Peptide-based methods represent new approaches to selectively produce nanostructures with potentially important functionality. Unfortunately, biocombinatorial methods can only select peptides with target affinity and not for the properties of the final material. In this work, we present evidence to demonstrate that materials-directing peptides can be controllably modified to substantially enhance particle functionality without significantly altering nanostructural morphology. To this end, modification of selected residues to vary the site-specific binding strength and biological recognition can be employed to increase the catalytic efficiency of peptide-capped Pd nanoparticles. These results represent a step toward the de novo design of materials-directing peptides that control nanoparticle structure/function relationships.
- Coppage, Ryan,Slocik, Joseph M.,Ramezani-Dakhel, Hadi,Bedford, Nicholas M.,Heinz, Hendrik,Naik, Rajesh R.,Knecht, Marc R.
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- G-/C-rich oligonucleotides stabilized pd nanocatalysts for the Suzuki coupling reaction under mild conditions
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Pd nanoparticles with narrow size distributions between 1.3 and 3.3 nm are prepared using G-/C-rich oligonucleotide as the template. These DNA-Pd nanoparticles efficiently catalyze the Suzuki coupling reaction and exhibit highly catalytic activities under mild conditions, which are greatly dependent upon the particle size of Pd nanoparticles besides the DNA sequence. For the coupling reaction of iodobenzene and phenylboronic acid at 60 C in the presence of KOH, it can be achieved high TOF value of 2646 mol biphenyl (mol Pd × h)-1 over AG22-Pd and 3640 mol biphenyl (mol Pd × h) -1 over CT22-Pd. Under the optimal experimental conditions, the yield of 100 % in biphenyl is obtained with only 0.0055 mol% AG22-Pd at 60 C for 1 h in the solvent of EtOH/H2O (1:2) using Na2CO3 or K2CO3 as the base. It is illustrated that G-/C-rich oligonucleotides are promising templates to modulate easily the morphology of Pd nanoparticles in aqueous solution with high catalytic activity.
- Li, Wei,Fu, Yingming,Fu, Yan,Wang, Xian,Zhang, Jinli
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- A new family of oxime palladacycles mixed with unsymmetrical phosphorus ylides; synthesis, structural, cytotoxicity and catalytic activity studies
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In the present investigation, the reactivity of an oxime-derived palladacycle [Pd{C,N–C6H4{C(Me) = NOH}-2}(μ-Cl)]2 toward various unsymmetrical phosphorus ylides has been studied. When the ylide was added to a solution of
- Samiee, Sepideh,Shiralinia, Ahmadreza,Hoveizi, Elham,Gable, Robert W.
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- Rapid and amenable Suzuki coupling reaction in water using microwave and conventional heating
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It is possible to prepare biaryls in good yield very rapidy (5-10 min) on small (1 mmol) and larger (10-20 mmol) scales from aryl halides and phenylboronic acid using water as a solvent and palladium acetate as catalyst. The reaction can be performed equally well using microwave and conventional heating, showing that using these conditions probably no nonthermal microwave effects are associated with the impressive speed of the reaction.
- Leadbeater, Nicholas E.,Marco, Maria
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- Elucidation of peptide effects that control the activity of nanoparticles
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A lot of pep: Simple changes to the sequence of peptide nanostructures were found to maintain stability and enhance the activity of peptide-based palladium nanocatalysts. A hlstidine to alanine substitution in the peptide chain afforded an increase in turnover frequency from 2234 to 5224, which suggests that the peptide modulates the functionality of bioinspired nanomaterials. (Figure presented)
- Coppage, Ryan,Slocik, Joseph M.,Sethi, Manish,Pacardo, Dennis B.,Naik, Rajesh R.,Knecht, Marc R.
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- Langmuir-Blodgett films of cyclopalladated ferrocenylimine: preparation, characterization, and application in Suzuki coupling reaction
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Langmuir monolayer and Langmuir-Blodgett (LB) films of cyclopalladated ferrocenylimine 1 were prepared and characterized. The surface pressure (π)-area (A) isotherm of complex 1 indicated the formation of highly condensed monolayer on the subphase. Ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopy showed that complex 1 monolayer was transferred successfully onto solid supports. Atomic force microscopy (AFM) image suggested that LB films transferred on the solid substrate were well-ordered, homogeneous. Cyclic voltammograms of LB films deposited on glassy carbon electrodes showed quasi-reversible oxidation/reduction waves of ferrocene moiety. From the average thickness of monolayer, the hydrocarbon chain could be fairly directed perpendicular to the substrates. Finally, LB films of complex 1 presented a largely improved catalytic efficiency for Suzuki reaction with respect to its cast films and homogeneous reactions under the same conditions. The results might have an implication on the catalytic mechanism of this reaction.
- Mu, Bing,Li, Tiesheng,Li, Chenghuan,Liu, Pingping,Shang, Wei,Wu, Yangjie
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- Stepwise benzylic oxygenation via uranyl-photocatalysis
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Stepwise oxygenation at the benzylic position (1°, 2°, 3°) of aromatic molecules was comprehensively established under ambient conditions via uranyl photocatalysis to produce carboxylic acids, ketones, and alcohols, respectively. The accuracy of the stepwise oxygenation was ensured by the tunability of catalytic activity in uranyl photocatalysis, which was adjusted by solvents and additives demonstrated through Stern–Volmer analysis. Hydrogen atom transfer between the benzylic position and the uranyl catalyst facilitated oxygenation, further confirmed by kinetic studies. Considerably improved efficiency of flow operation demonstrated the potential for industrial synthetic application.
- Hu, Deqing,Jiang, Xuefeng
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supporting information
p. 124 - 129
(2022/01/19)
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- Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
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A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
- Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
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supporting information
p. 2020 - 2024
(2022/03/31)
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- Palladium nanoparticles capped by thermoresponsive N-heterocyclic carbene: Two different approaches for a comparative study
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In this article, we reported the synthesis of thermoresponsive palladium nanoparticles, stabilized by polymer-tagged N-heterocyclic carbenes (NHCs), using two different approaches. In one case, the nanoparticles were synthesized from the NHC–palladium complex, while in other cases, palladium nanoparticles and NHC were synthesized simultaneously for the in situ cappings of the nanomaterial. While the thermoresponsive nature of the nanomaterials was observed in both cases, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analyses showed distinct characteristics in the thermal behavior of those materials. High-resolution transmission electron microscopic (HRTEM) and scanning electron microscopic studies separately revealed temperature-dependent aggregation in both cases although separate patterns were observed when the nanomaterials were synthesized using different approaches. Finally, both the nanomaterials were successfully used as a recyclable catalyst for Suzuki reactions in an aqueous medium, with slightly different catalytic activity, plausibly due to variations in the size of the nanoparticles.
- Gayathri, Varnakumar,Pentela, Nagaraju,Samanta, Debasis
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- Magnetic covalently immobilized nickel complex: A new and efficient method for the Suzuki cross-coupling reaction
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In this study, an efficient procedure was reported to prepare Fe3O4@SiO2 magnetic nanoparticles (MNPs) with immobilized nickel NPs. In order to increase the activity of this catalyst, creatine as a ligand with high content of nitrogen atoms was linked onto the magnetic core–shell structure. Then, Ni(II) ions were coordinated on the surface of the silica-coated MNPs and reduced to Ni(0) NPs to obtain the final catalyst. The catalytic activity of the prepared catalyst was studied for the synthesis of biaryl derivatives via the Suzuki–Miyaura cross-coupling reaction in high yields. The catalyst could also be recovered and reused with no loss of activity over five successful runs.
- Keyhaniyan, Mahdi,Khojastehnezhad, Amir,Eshghi, Hossein,Shiri, Ali
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- Pd salen complex@CPGO as a convenient, effective heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions
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A Pd(II) Schiff base complex supported on graphene oxide nanosheets (Pd(II) salen@CPGO) has been synthesized and characterized by FT-IR, ICP-AES, XRD, SEM/EDX and TEM. The synthesized nanocatalyst has been found to be an efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki coupling reactions. Pd(II) salen@CPGO could be separated and recovered easily from the reaction mixture and recycled several times without a discernible decrease in its catalytic activity. The construction of a solid sheet-supported Pd catalyst would be expected to be a promising system to perform heterogeneous catalytic reactions.
- Ghabdian, Mahdieh,Nasseri, Mohammad Ali,Allahresani, Ali,Motavallizadehkakhky, Alireza
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p. 1713 - 1728
(2018/05/25)
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- NiFe2O4@SiO2@ZrO2/SO42-/Cu/Co nanoparticles: A novel, efficient, magnetically recyclable and bimetallic catalyst for Pd-free Suzuki, Heck and C-N cross-coupling reactions in aqueous media
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The novel heterogeneous bimetallic nanoparticles of Cu-Co were synthesized based on magnetic nanoparticles, and the magnetic nanocatalyst was characterized by XRD, FE-SEM, EDX mapping, BET, TEM, HRTEM, FTIR, TGA, and VSM. This catalyst was successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C-N cross-coupling reactions with various aryl halides (iodides, bromides, and chlorides as challengeable substrates), with olefins, phenylboronic acid, and amines, respectively. We considered the rise of synergetic effects from the different Lewis acid and Br?nsted acid sites present in the catalyst. The catalyst was synthesized with cheap, available materials and a simple synthesis method. The catalyst can be separated easily using an external magnet. It was recycled for more than ten runs without a sensible loss of its catalytic activity, and no significant leaching of the Cu and Co quantity was observed. The significant benefits of the method are high-level generality, simple operation, and there are no heavy metals and toxic solvents. This is a quick, easy, efficacious and environmentally friendly protocol, and no by-products are formed in the reaction. These features make it an appropriate practical alternative protocol. In comparison with recent works, the other advantage of this catalyst is the synthesis of a wide variety of C-C and C-N bond derivatives (more than 40 derivatives). The other significant advantage is the low temperature of the reaction and the use of the least possible amount of the catalyst (0.003 g). The efficiency was good to excellent and the catalyst selectivity has been high. We aspire that our study inspires more interest to design novel catalysts based on using low-cost metal ions (such as cobalt and copper) in the cross-coupling reactions. This journal is
- Alavi G., Seyyedeh Ameneh,Nasseri, Mohammad Ali,Kazemnejadi, Milad,Allahresani, Ali,Hussainzadeh, Mahdi
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p. 7741 - 7757
(2021/05/13)
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- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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- Isotruxene-based porous polymers as efficient and recyclable photocatalysts for visible-light induced metal-free oxidative organic transformations
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Two new isotruxene-based porous polymers were prepared and demonstrated to be highly efficient, metal-free heterogeneous photocatalysts for oxidative transformations using air as the mild oxidant under visible-light irradiation. Both catalysts show excellent recyclability. In addition, the reactions can be performed in water, further indicating the greenness of this method. This journal is
- Zhang, Haowen,Zhang, Xiao,Zheng, Ying,Zhou, Cen
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p. 8878 - 8885
(2021/11/27)
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- One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
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Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
- Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
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supporting information
p. 18150 - 18155
(2021/12/09)
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- Photo-induced deep aerobic oxidation of alkyl aromatics
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Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
- Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
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p. 1487 - 1492
(2021/07/10)
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- Bimetallic Cooperative Catalysis for Decarbonylative Heteroarylation of Carboxylic Acids via C-O/C-H Coupling
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Cooperative bimetallic catalysis is a fundamental approach in modern synthetic chemistry. We report bimetallic cooperative catalysis for the direct decarbonylative heteroarylation of ubiquitous carboxylic acids via acyl C-O/C-H coupling. This novel catalytic system exploits the cooperative action of a copper catalyst and a palladium catalyst in decarbonylation, which enables highly chemoselective synthesis of important heterobiaryl motifs through the coupling of carboxylic acids with heteroarenes in the absence of prefunctionalization or directing groups. This cooperative decarbonylative method uses common carboxylic acids and shows a remarkably broad substrate scope (>70 examples), including late-stage modification of pharmaceuticals and streamlined synthesis of bioactive agents. Extensive mechanistic and computational studies were conducted to gain insight into the mechanism of the reaction. The key step involves intersection of the two catalytic cycles via transmetallation of the copper–aryl species with the palladium(II) intermediate generated by oxidative addition/decarbonylation.
- Liu, Chengwei,Ji, Chong-Lei,Zhou, Tongliang,Hong, Xin,Szostak, Michal
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supporting information
p. 10690 - 10699
(2021/04/09)
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- Method for synthesizing acetophenone or benzoic acid compound by oxidizing toluene compound
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The invention provides a method for synthesizing an acetophenone or benzoic acid compound through oxidation of a toluene compound, and belongs to the field of organic synthesis. The method for synthesizing the acetophenone or benzoic acid compound through oxidation of the toluene compound comprises the following step of: under the action of a reaction catalyst and an initiator, illuminating the toluene compound in an oxygen-containing atmosphere in a solvent to obtain the acetophenone compound or the benzoic acid compound, wherein the reaction catalyst is lanthanide series rare earth metal salt, and the initiator is a C1-C6 alcohol compound. The method has the advantages of abundant and easily available substrate sources, mild reaction conditions, good compatibility of substrate functional groups, simple operation, high reaction safety, low cost and the like.
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Paragraph 0035-0040
(2021/05/12)
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- Photoinduced FeCl3-Catalyzed Alkyl Aromatics Oxidation toward Degradation of Polystyrene at Room Temperature?
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While polystyrene is widely used in daily life as a synthetic plastic, the subsequently selective degradation is still very challenging and highly required. Herein, we disclose a highly practical and selective reaction for the catalytically efficient oxidation of alkyl aromatics (including 1°, 2°, and 3° alkyl aromatics) to carboxylic acids. While dioxygen was used as the sole terminal oxidant, this protocol was catalyzed by the inexpensive and readily available ferric compound (FeCl3) with irradiation of visible light (blue LEDs) under only 1 atmosphere of O2 at room temperature. This system could further facilitate the selective degradation of polystyrene to benzoic acid, providing an important and practical tool to generate high-value chemical from abundant polystyrene wastes.
- Zhang, Guoxiang,Zhang, Zongnan,Zeng, Rong
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supporting information
p. 3225 - 3230
(2021/09/28)
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- An Anionic, Chelating C(sp3)/NHC ligand from the Combination of an N-heterobicyclic Carbene and Barbituric Heterocycle
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The coordination chemistry of the anionic NHC1-based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) platform substituted at the C5 position by an anionic barbituric heterocycle was studied with d6(Ru(II), Mn(I)) and d8(Pd(II), Rh(I), Ir(I), Au(III)) transition-metal centers. While the anionic barbituric heterocycle is planar in the zwitterionic NHC precursor 1·H, NMR spectroscopic analyses supplemented by X-ray diffraction studies evidenced the chelating behavior of ligand 1-through the carbenic and the malonic carbon atoms in all of the complexes, resulting from a deformation of the lateral barbituric heterocycle. The complexes were obtained by reaction of the free carbene with the appropriate metal precursor, except for the Au(III) complex 10, which was obtained by oxidation of the antecedent gold(I) complex [AuCl(1)]?with PhICl2as an external oxidant. During the course of the process, the kinetic gold(I) intermediate 9 resulting from the oxidation of the malonic carbon of the barbituric moiety was isolated upon crystallization from the reaction mixture. The νCOstretching frequencies recorded for complex [Rh(1)(CO)2] (5) demonstrated the strong donating character of the malonate-C(sp3)/NHC ligand 1-. The ruthenium complex [Ru(1)Cl(p-cymene)] (11) was implemented as a precatalyst in the dehydrogenative synthesis of carboxylic acid derivatives from primary alcohols and exhibited high activities at low catalyst loadings (25-250 ppm) and a large tolerance toward functional groups.
- Benaissa, Idir,Gajda, Katarzyna,Vendier, Laure,Lugan, No?l,Kajetanowicz, Anna,Grela, Karol,Michelet, Véronique,César, Vincent,Bastin, Stéphanie
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p. 3223 - 3234
(2021/09/30)
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- Heterogeneous vanadium-catalyzed oxidative cleavage of olefins for sustainable synthesis of carboxylic acids
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The development of green and sustainable processes to synthesize active pharmaceutical ingredients and key starting materials is a priority for the pharmaceutical industry. A green and sustainable protocol for the oxidative cleavage of olefins to produce pharmaceutically and biologically valuable carboxylic acids is achieved. The developed protocol involves 70% aq. TBHP as an oxidant over a heterogeneous vanadium catalyst system. Notably, the synthesis of industrially important azelaic acid from various renewable vegetable oils is accomplished. The catalyst could be recycled for up to 5 cycles without significant loss in yield and the protocol was successfully demonstrated at the gram-scale.
- Upadhyay, Rahul,Rana, Rohit,Sood, Aakriti,Singh, Vikash,Kumar, Rahul,Srivastava, Vimal Chandra,Maurya, Sushil K.
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supporting information
p. 5430 - 5433
(2021/06/09)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- Synthesis of tetranuclear complex of Pd(II) with thiosemicarbazone ligands derived from 2-quinolone and its catalytic evaluation in Suzuki–Miyaura-type coupling reactions and alkoxylation of chloroquinolines
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A tetranuclear palladium(II) complex [(Pd(H-6MOQtsc-Ph))4] was obtained from the reaction between 6-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4(N)-phenylthiosemicarbazone [H2-6MOQtsc-Ph] and K2[PdCl4]. The ligand and the Pd(II) complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV–visible and 1H NMR spectroscopy. X-ray diffraction studies confirmed the tetrameric nature of the complex with the coordination of ligand through quinolone carbonyl, azomethine nitrogen and thiolate sulfur atoms, and the fourth site is occupied by 2-quinolone nitrogen atom of the adjacent ligand. The synthesized complex was tested as catalyst in Suzuki–Miyaura coupling reaction between various chloroquinoline derivatives with phenylboronic acid. The reactions afforded unexpected C-alkoxylated (C-O coupling) products instead of more expected C-arylated (C-C coupling) products in the respective alcoholic mediums. However, the reactions with traditional aryl halides probed with very good yield of the corresponding C-C coupling products.
- Nandhini, Sundar,Dharani, Sivadasan,Elamathi, Chennakrishnan,Dallemer, Frederic,Prabhakaran, Rathinasabapathi
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- Tellurium-Ligated Pd(II) Complex of Bulky Organotellurium Ligand?as a Catalyst of Suzuki coupling: First Report on In Situ Generation of Bimetallic Alloy?‘Telluropalladinite’ (Pd9Te4)?Nanoparticles and Role in Highly Efficient Catalysis
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A novel,?easily synthesizable, air and moisture insensitive organotellurium ligand L1 and its Pd(II) complex (i.e., 1) Pd(L1)Cl2] (L1: pyren-1-yl-CH=N–(CH2)2TePh] have been synthesized. Both L1 and 1 have been characterized using 1H, 13C and 125Te NMR spectroscopy. Mass spectrometric and single crystal X-ray diffraction techniques have also been used to corroborate the structure of the Pd(II)-complex in which ligand is coordinated with palladium in bidentate (Te, N) mode. The Pd(II) complex has been explored as a catalyst for Suzuki–Miyaura coupling reaction. During the course of catalysis, it dispenses the nanoparticles of palladium rich alloy ‘telluropalladinite’ (Pd9Te4). Among catalytically active Te/Se/S-ligated complexes studied during preceding 20?years, it shows an extremely high efficiency (TON values: upto 107 for coupling reactions of ArBr). It has also been found competent enough to catalyze the reactions of least reactive ArCl within 3?h. Graphic Abstract: [Figure not available: see fulltext.]
- Arora, Aayushi,Kumar, Arun,Kumar, Sushil,Oswal, Preeti,Rao, Gyandshwar K.,Singh, Ajai K.
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- Regioselective nitration of a biphenyl derivative to derive a fluorescent chloride sensor
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Methyl 2′-aminobiphenyl-4-carboxylate, an optical chloride sensor has been synthesized via Suzuki-Miyaura cross-coupling followed by regioselective nitration. In general biphenyl systems are prone to undergo poly nitration whenever they are subjected to nitration via different nitrating agents. But in this present work, a highly selective nitration in the 2′ position of methyl biphenyl-4-carboxylate was achieved using 70% HNO3 and acetic anhydride to derive 3. Upon reduction, 3 produces 4 which shows bright blue emission in different organic solvents. In presence of chloride ion the blue emission of the sensor changes to enhanced bright green emission. The chloride sensing has also been explored using other spectroscopic techniques such as 1H NMR, UV–vis spectroscopy, and theoretical study.
- Das, Tanmay,Mohar, Mrittika,Bag, Arijit
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supporting information
(2021/01/25)
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- Pd(OAc)2-biuret: A highly efficient, low cost and phosphine-free catalyst system for biaryl synthesis under aerobic conditions at room temperature
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A highly efficient, less expensive and phosphine-free protocol for the Suzuki-Miyaura cross-coupling reactions of aryl halides and aryl boronic acids in iPrOH-H2O solvent under aerobic conditions has been developed. The results demonstrate that the biuret played a crucial role and making this protocol highly efficient. The Pd(OAc)2-biuret system exhibited superb catalytic activity towards the Suzuki-Miyaura cross-coupling reaction of a wide range of aryl halides with aryl boronic acids at room temperature, giving high yields even under very low catalytic loading. This system offers an attractive alternative to the existing protocols since the reaction proceeds in green solvent at room temperature with working simplicity, shorter reaction time, cost-effectiveness and provides the desired products in high yields. The effect of solvent, base as well as catalyst loading on the cross-coupling reaction of aryl halide with arylboronic acid is also described.
- Saikia, Bishwajit
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- Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
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Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
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p. 2842 - 2850
(2021/02/01)
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- Crosslinked polymer encapsulated palladium nanoparticles for catalytic reduction and Suzuki reactions in aqueous medium
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Acrylamide and N-isopropylacrylamide were copolymerized in the presence of a N,N-methylenebisacrylamide crosslinker to obtain poly(N-isopropylacrylamide-co-acrylamide) [P(NA)] polymer colloidal particles. Pd nano crystals with diameter of 4–8 nm were loaded into the [P(NA)] microgels by reduction of [PdCl4]-2 within dispersion of polymer microgels. The Pd NPs-loaded hybrid microgels were analysed by TEM, STEM, EDX and XRD. The catalytic ability of the Pd-[P(NA)] system was investigated towards reductive transformation of nitroarenes into corresponding aryl amines and Suzuki coupling transformation in a green solvent, H2O. The progress of catalytic reaction was examined by thin layer chromatography (TLC). Different reactants were effectively converted into their corresponding products with great to fabulous yields (extending from 75 to 97%) under gentle reaction conditions. The Pd-[P(NA)] catalyst is stable for long time and can be utilized numerous times without any notable loss in its catalytic action.
- Begum, Robina,Farooqi, Zahoor H.,Xiao, Jianliang,Ahmed, Ejaz,Sharif, Ahsan,Irfan, Ahmad
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- Synthesis and characterization of mononuclear oxime-based palladacycles incorporating phosphorus ylides: application as a catalyst in Suzuki cross coupling reactions and their biological activities
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The synthesis of mononuclear oxime-based palladacycles of the type [Pd{C,N-C6H4{C(Me)=NOH}-2}(Ph2PCH2CH2PPh2C(H)C(O)C6H4X)]ClO4(X = Cl (1), Br (2), NO2
- Shiralinia, Ahmadreza,Samiee, Sepideh,Hoveizi, Elham
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p. 2542 - 2557
(2021/10/25)
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- Hexagonal Boron Nitride Supported N-Heterocyclic Carbene-Palladium(II): A New, Efficient and Recyclable Heterogeneous Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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Abstract: In this study, a new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed and synthesized. The structure of the h-BN@NHC-Pd heterogeneous catalyst was characterized by various techniques such as Fourier transform infrared spectra (FT-IR), ultraviolet–visible spectroscopy (UV–Visible), inductively coupled plasma-optical emission spectroscopy (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). Then catalytic activity of h-BN@NHC-Pd heterogeneous catalyst was studied in the Suzuki–Miyaura cross-coupling reactions between aryl halides and arylboronic acids in aqueous medium at room temperature. The effects of varying solvents, bases, temperature, time and catalytic ratios on the performance of the Suzuki–Miyaura cross-coupling reaction were investigated. Moreover, h-BN@NHC-Pd heterogeneous catalyst could be easily recovered through simple filtration or centrifugation method and could be reused five times without significant loss of its catalytic efficiency. Furthermore, stability of the h-BN@NHC-Pd heterogeneous catalyst after recycling was confirmed through FESEM and FT-IR techniques. The h-BN@NHC-Pd heterogeneous catalyst shows remarkable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easily separable and high stability without leaching. Graphic Abstract: A new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed, synthesized, characterized and catalytic activity was studied in the Suzuki–Miyaura cross-coupling reactions. [Figure not available: see fulltext.]
- Antony, Arnet Maria,Kandathil, Vishal,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
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p. 1293 - 1308
(2020/10/06)
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- Design, synthesis, and biological studies of novel 3-benzamidobenzoic acid derivatives as farnesoid X receptor partial agonist
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Farnesoid X receptor (FXR), a bile acid-activated nuclear receptor, regulates the metabolism of bile acid and lipids as well as maintains the stability of internal environment. FXR was considered as a therapeutic target of liver disorders, such as drug-induced liver injury, fatty liver and cholestasis. The previous reported FXR partial agonist 6 was a suitable lead compound in terms of its high potent and low molecular size, while the docking study of compound 6 suggested a large unoccupied hydrophobic pocket, which might be provided more possibility of structure-activity relationship (SAR) study. In this study, we have performed comprehensive SAR and molecular modeling studies based on lead compound 6. All of these efforts resulted in the identification of a novel series of FXR partial agonists. In this series, compound 41 revealed the best activity and strong interaction with binding pocket of FXR. Moreover, compound 41 protected mice against acetaminophen-induced hepatotoxicity by the regulation of FXR-related gene expression and improving antioxidant capacity. In summary, these results suggest that compound 41 is a promising FXR partial agonist suitable for further investigation.
- Hu, Lijun,Ren, Qiang,Deng, Liming,Zhou, Zongtao,Cai, Zongyu,Wang, Bin,Li, Zheng
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supporting information
(2020/12/25)
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Oxidative α-C-C Bond Cleavage of 2° and 3° Alcohols to Aromatic Acids with O2at Room Temperature via Iron Photocatalysis
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The selective α-C-C bond cleavage of unfunctionalized secondary (2°) and tertiary alcohols (3°) is essential for valorization of macromolecules and biopolymers. We developed a blue-light-driven iron catalysis for aerobic oxidation of 2° and 3° alcohols to acids via α-C-C bond cleavages at room temperature. The first example of oxygenation of the simple tertiary alcohols was reported. The iron catalyst and blue light play critical roles to enable the formation of highly reactive O radicals from alcohols and the consequent two α-C-C bond cleavages.
- Zhang, Zongnan,Zhang, Guoxiang,Xiong, Ni,Xue, Ting,Zhang, Junjie,Bai, Lu,Guo, Qinyue,Zeng, Rong
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supporting information
p. 2915 - 2920
(2021/05/05)
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- Triptycene carbene allyl palladium compound and application thereof
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The invention relates to a triptycene carbene allyl palladium compound and application thereof. The structural formula of the triptycene carbene allyl palladium compound is a formula I or a fotmula II. Compared with a conventional metal palladium catalyst, the triptycene carbene allyl palladium compound is easy and convenient to prepare, high in yield and suitable for various substrates, the use amount of a catalyst can be reduced to one ten thousandth, and the compound has a good catalytic effect on various metal palladium catalytic reactions. The compound has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0062-0069
(2021/06/02)
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- Triptycene carbene tridentate metal coordination compound and application thereof
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The invention relates to a triptycene carbene tridentate metal coordination compound, wherein the structural formula of the triptycene carbene tridentate metal coordination compound is shown in the specification. According to the invention, the compound is correct in detection; based on the problems that a metal catalyst used in an organic reaction at the present stage cannot be suitable for various substrates, the catalyst content is high, the cost is high, long-time storage is difficult, and the like, the triptycene carbene tridentate metal coordination compound provided by the invention is used as a catalyst, the preparation is simple and convenient, the yield is high, the triptycene carbene tridentate metal coordination compound is suitable for various substrates, the usage amount of the catalyst can be reduced to one ten thousandth, and the triptycene carbene tridentate metal coordination compound has a better catalytic effect on various metal catalytic reactions, and has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0068-076
(2021/06/22)
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- Cobalt-catalyzed cross-coupling reactions of aryl- And alkylaluminum derivatives with (hetero)aryl and alkyl bromides
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A simple cobalt complex, such as Co(phen)Cl2, turned out to be a highly efficient and cheap precatalyst for a host of cross-coupling reactions involving aromatic and aliphatic organoaluminum reagents with aryl, heteroaryl and alkyl bromides. New C(sp2)-C(sp2) and C(sp2)-C(sp3) bonds were formed in good to excellent yields and with high chemoselectivity, under mild reaction conditions.
- Dilauro, Giuseppe,Messa, Francesco,Bona, Fabio,Perrone, Serena,Salomone, Antonio
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supporting information
p. 10564 - 10567
(2021/10/19)
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- B-Ring-extended flavonol-based photoCORM: activated by cysteine-ratiometric fluorescence sensing and accurate control of linear CO release
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The first B-ring-extended (to biphenyl) flavonol-based Cys-ratiometric fluorescent probeB-bph-fla-acr(2-([1,1′-biphenyl]-4-yl)-4-oxo-4H-chromen-3-yl acrylate) is developed.B-bph-fla-acrcan ratiometrically sense and non-ratiometrically image endogenous and exogenous cysteine (Cys) in living HeLa cells and zebrafish rapidly (45 s), selectively (vs.homocysteine and glutathione), sensitively (detection limit: 18.5 nM), and with a large Stokes shift (186 nm). Quantitatively released (from the reaction ofB-bph-fla-acrwith Cys) fluorophoreB-bph-fla-OH(2-([1,1′-biphenyl]-4-yl)-3-hydroxy-4H-chromen-4-one) is designed as a photoCORM (photo-triggered CO releasing molecule). Under O2and visible light irradiation, the amount of CO released byB-bph-fla-OHcan be accurately controlled linearly by adjusting the light irradiation intensity, irradiation time, or photoCORM dose. This process is accompanied by fluorescence quenching; therefore, the location of the photoCORM and the CO release process can be monitored in real time.B-bph-fla-acrand all reaction products exhibit good membrane permeability and low toxicity for living HeLa cells. In living HeLa cells and zebrafish,B-bph-fla-acrcan image endogenous and exogenous Cys, and the releasedB-bph-fla-OHcan photo-release CO under O2at room temperature. This study is the first to combine a B-ring-extended flavonol-based fluorescent probe (for the effective ratiometric sensing and non-ratiometric imaging of endogenous and exogenous Cysin vitroandin vivo) with a photoCORM (Cys-activated, visible light-triggered linear CO release under O2). Our study provides important insights into the biological roles of Cys and CO, as well as a reliable method for safely supplying accurately controlled amounts of CO to living systems, thereby facilitating the development of convenient clinical diagnostic molecular tools and therapeutic prodrugs.
- Sun, Ying-Ji,Yu, Chao
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supporting information
p. 8263 - 8271
(2021/10/20)
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- Cobalt-Catalyzed Deprotection of Allyl Carboxylic Esters Induced by Hydrogen Atom Transfer
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A brief, efficient method has been developed for the removal of the allyl protecting group from allyl carboxylic esters using a Co(II)/TBHP/(Me2SiH)2O catalytic system. This facile strategy displays excellent chemoselectivity, functional group tolerance, and high yields. This transformation probably occurs through the hydrogen atom transfer process, and a Co(III)-six-membered cyclic intermediate is recommended.
- Li, Nan,Gui, Yizhen,Chu, Mengqi,You, Mengdi,Qiu, Xiaohan,Liu, Hejia,Wang, Shiang,Deng, Meng,Ji, Baoming
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supporting information
p. 8460 - 8464
(2021/11/13)
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- A self-assembling NHC-PD-loaded calixarene as a potent catalyst for the Suzuki-Miyaura cross-coupling reaction in water
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Nanoformulated calix[8]arenes functionalized with N-heterocyclic carbene (NHC)palladium complexes were found to be efficient nano-reactors for Suzuki-Miyaura cross-coupling reactions of water soluble iodo- and bromoaryl compounds with cyclic triol arylborates at low temperature in water without any organic co-solvent. Combined with an improved one-step synthesis of triol arylborates from boronic acid, this remarkably efficient new tool provided a variety of 40-arylated phenylalanines and tyrosines in good yields at low catalyst loading with a wide functional group tolerance.
- Abdellah, Ibrahim,Couvreur, Patrick,Desma?le, Didier,Huc, Vincent,Martini, Cyril,Mougin, Julie,Pecnard, Shannon,Peramo, Arnaud
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- Palladium-decorated o-phenylenediamine-functionalized Fe3O4/SiO2 magnetic nanoparticles: A promising solid-state catalytic system used for Suzuki–Miyaura coupling reactions
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Palladium-supported o-phenylenediamine-functionalized Fe3O4 magnetic nanoparticles are presented. A convenient synthetic route for the nanocatalyst and also its application in Suzuki–Miyaura coupling of various aryl halides with phenylboronic acids are described. A high reaction yield (98%) was been obtained in a short reaction time (10 min) through use of this highly efficient nanocatalyst. From a mechanistic aspect, firstly, effective electronic interactions between heteroatoms such as oxygen and Pd(II) provide a suitable condition for covalent bonding by the ingredients in the Suzuki–Miyaura coupling reaction. Secondly, Pd(II) is converted to Pd(0) by use of sodium borohydride in the presence of triphenylphosphine in basic conditions, and then it plays a main role in the catalytic process. However, the most distinguished properties of this catalytic system are the ease of catalyst separation and great reusability. The palladium-supported o-phenylenediamine-functionalized Fe3O4 nanoparticles can be easily recovered by use of an external magnet and can reused at least ten times with no significant decline in catalytic activity. This novel system was structurally characterized by various analytical methods, and the results obtained are well interpreted in the context.
- Maleki, Ali,Taheri-Ledari, Reza,Ghalavand, Reza,Firouzi-Haji, Razieh
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- A Co-Cu bimetallic magnetic nanocatalyst with synergistic and bifunctional performance for the base-free Suzuki, Sonogashira, and C-N cross-coupling reactions in water
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A novel magnetically recyclable bimetallic catalyst was prepared by anchoring imidazolium moiety and PEG chains on Fe3O4 NPs and named as Fe3O4?PEG/Cu-Co. It was found to be a powerful catalyst for the Sonogashira, Suzuki, and C-N cross-coupling reactions in water as a green solvent without the need for any external base. Fe3O4?PEG/Cu-Co was well characterized with FT-IR, FE-SEM, TEM, VSM, EDX, ICP, UV-visible, CV, and XPS analyses. Optimum ranges of parameters such as time, temperature, and amount of catalyst were investigated by Design-Expert 10.0.7 software for C-C Suzuki, Sonogashira, and C-N cross-coupling reactions to find the optimum conditions. The catalyst was compatible with a variety of aryl halides and N-arenes and gave favorable coupling products with good to high yields for all of them. Hot filtration and Hg poisoning tests involving the nanocatalyst revealed the stability, low metal leaching, and heterogeneous nature of the catalyst. Reaction mechanisms were proposed by study of the UV-visible spectra in situ as well as hydroquinone tests during the progress of reactions. In situ XPS analysis was also used to study the reaction mechanism. To prove the synergistic performance of Co and Cu in the catalyst, its various homologues were synthesized and applied to a model reaction separately, and then their catalytic activities were investigated. Finally, the catalyst could be recovered from the reaction mixture simply, and reused for several cycles with a minimum loss in catalytic activity and performance.
- Allahresani, Ali,Kazemnejadi, Milad,Nasseri, Mohammad Ali,Rezazadeh, Zinat
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p. 10645 - 10660
(2020/09/18)
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- Palladium Supported on Silk Fibroin for Suzuki–Miyaura Cross-Coupling Reactions
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Silk fibroin supported Pd (Pd/SF) has been prepared and used as catalyst in Suzuki–Miyaura cross-coupling reactions in water/ethanol (4:1 v/v) mixture. The reactions proceed rapidly with aryl iodides and boronic acids with different electronic properties using low metal loading (0.38 mol-%). Pd/SF exhibits better recyclability compared to other biopolymer-supported Pd catalysts, up to nineteen cycles without loss of activity.
- Albano, Gianluigi,Farinola, Gianluca M.,Lo Presti, Marco,Milella, Antonella,Omenetto, Fiorenzo G.,Rizzo, Giorgio
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supporting information
p. 6992 - 6996
(2020/11/30)
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- Selective Solvent-Free and Additive-Free Oxidation of Primary Benzylic C–H Bonds with O2 Catalyzed by the Combination of Metalloporphyrin with N-Hydroxyphthalimide
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Abstract: A protocol for solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts to overcome the deficiencies encountered in current oxidation systems. The effects of reaction temperature, porphyrin structure, central metal, catalyst loading and O2 pressure were investigated systematically. For the optimized combination of T(2-OCH3)PPCo and NHPI, all the primary benzylic C–H bonds could be functionalized efficiently and selectively at 120 °C and 1.0?MPa O2 with aromatic acids as the primary products. The selectivity towards aromatic acids could reach up to 70–95% in the conversion of more than 30% for most of the substrates possessing primary benzylic C–H bonds in the metalloporphyrin loading of 0.012% (mol/mol). And the superior performance of T(2-OCH3)PPCo among the metalloporphyrins investigated was mainly attributed to its high efficiency in charge transfer and fewer positive charges around central metal Co (II) which favored the adduction of O2 to cobalt (II) forming the high-valence metal-oxo complex followed by the production of phthalimide N-oxyl radical (PINO) and the initiation of the catalytic oxidation cycle. This work would provide not only an efficient protocol in utilization of hydrocarbons containing primary benzylic C–H bonds, but also a significant reference in the construction of more efficient C–H bonds oxidation systems. Graphic Abstract: The solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts, and the highest selectivity towards aromatic acid reached up to 95.1% with the conversion of 88.5% in the optimized combination of T(2-OCH3)PPCo and NHPI.[Figure not available: see fulltext.].
- Shen, Hai-Min,Qi, Bei,Hu, Meng-Yun,Liu, Lei,Ye, Hong-Liang,She, Yuan-Bin
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p. 3096 - 3111
(2020/04/29)
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- Method for catalytic oxidation of toluene and derivatives thereof by metalloporphyrin
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The invention relates to a method for catalytic oxidation of toluene and derivatives thereof by metalloporphyrin. The method comprises the following steps: dispersing metalloporphyrin and N-hydroxyphthalimide (NHPI) into methylbenzene and derivatives thereof, sealing the reaction system, heating to 70-130 DEG C while stirring, introducing oxygen to 0.2-2.0 MPa, keeping the set temperature and oxygen pressure, carrying out reactions for 8 hours under stirring, and carrying out after-treatment on the reaction solution to obtain the product aromatic acid. The method has the advantages of no solvent, no additive, mild conditions, higher selectivity to aromatic acids and good tolerance to substrates. The method not only can effectively oxidize hydrocarbon containing primary benzyl C-H bonds, but also can provide important reference for constructing a more effective C-H bond oxidation system, and is a novel efficient and feasible selective catalytic oxidation method for methylbenzene and derivatives thereof.
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Paragraph 0073-0074
(2020/09/30)
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids
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A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability"of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
- Kim, Seongwoo,Lee, Ha-Eun,Suh, Jong-Min,Lim, Mi Hee,Kim, Min
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supporting information
p. 17573 - 17582
(2020/12/22)
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- Cobalt-catalyzed carboxylation of aryl and vinyl chlorides with CO2
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The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields.
- Wang, Yanwei,Jiang, Xiaomei,Wang, Baiquan
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supporting information
p. 14416 - 14419
(2020/12/01)
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- Cobalt-Catalyzed Reductive Carboxylation of Aryl Bromides with Carbon Dioxide
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Cobalt-catalyzed reductive carboxylation of aryl bromides with carbon dioxide has been developed. The reaction proceeded under one atm pressure of CO2 at 40 °C in the presence of cobalt iodide/2,2′-bipyridine catalysts and zinc dust as a reducing reagent. Various aryl bromides could be converted to the corresponding carboxylic acids in good to high yields. Preliminary mechanistic experiments ruled out intervention of intermediate organozinc species for carboxylation with CO2, thus suggesting a direct CO2 insertion into the corresponding ArCoBr species. (Figure presented.).
- Hang, Wei,Yi, Yaping,Xi, Chanjuan
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supporting information
p. 2337 - 2341
(2020/04/30)
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- Catalytic Oxidative Cleavage Reactions of Arylalkenes by tert-Butyl Hydroperoxide - A Mechanistic Assessment
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Oxidative cleavage reactions of arylalkenes by tert-butyl hydroperoxide that occur by free radical processes provide access to carboxylic acid or ketone products. However, the pathway to these cleavage products is complex, initiated by regioselective oxygen radical addition to the carbon-carbon double bond. Subsequent reactions of the initially formed benzyl radical lead eventually to carbon-carbon cleavage. Thorough investigations of these reactions have identified numerous reaction intermediates that are on the pathways to final product formation, and they have identified a new synthetic methodology for the synthesis of peroxy radical addition-induced hydroperoxide formation.
- Su, Yong-Liang,De Angelis, Luca,Tram, Linh,Yu, Yang,Doyle, Michael P.
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p. 3728 - 3741
(2020/03/23)
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- High photocatalytic activity of a NiO nanodot-decorated Pd/SiC catalyst for the Suzuki-Miyaura cross-coupling of aryl bromides and chlorides in air under visible light
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The Suzuki-Miyaura cross-coupling reaction is an effective process for C-C bond formation in organic synthesis. Herein, we report a NiO nanodot-decorated Pd/SiC catalyst, synthesized by atomic layer deposition, which shows high photocatalytic activity for the Suzuki-Miyaura coupling of both aryl bromides and chlorides with phenylboronic acid at 30 °C in air. The Mott-Schottky contact in SiC/Pd enhances the rapid transfer of the photogenerated electrons from SiC to Pd nanoparticles. Moreover, the energy different between the highest occupied molecular orbital of the ultrafine NiO nanodots and the Fermi level of Pd forces a spontaneous electron transfer from NiO to Pd. As a result, the concentrated electrons in the Pd nanoparticles can facilitate the cleavage of C-Br or C-Cl bonds, which normally requires rather high temperatures in thermal processes. The holes left on the SiC support can assist the cleavage of the C-B bond.
- Braunschweig, Holger,Guo, Xiang-Yun,Guo, Xiao-Ning,Hao, Cai-Hong,Jiao, Zhi-Feng,Marder, Todd B.,Qiao, Yan,Qin, Yong,Radius, Udo,Tian, Ya-Ming,Wang, Ying-Xiong,Zhang, Bin
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p. 517 - 524
(2020/07/21)
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- Cp2TiCl2-Catalyzed Carboxylation of Aryl Chlorides with Carbon Dioxide in the Presence of n-BuMgCl
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Cp2TiCl2-catalyzed carboxylation of aryl chlorides with carbon dioxide to afford benzoic acids in good yields has been achieved in the presence of n-BuMgCl. The reaction proceeds by a sequential magnesium halide exchange reaction and carboxylation with CO2 in a wide variety of aryl chlorides under mild conditions.
- Hang, Wei,Yi, Yaping,Xi, Chanjuan
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supporting information
p. 1476 - 1479
(2020/01/21)
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- Method for synthesizing biphenyl compound by taking suaeda salsa extract liquor as solvent
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The invention discloses a method for synthesizing a biphenyl compound by using suaeda salsa extract as a solvent in the technical field of organic chemical synthesis, which comprises the following steps: roasting suaeda salsa in a muffle furnace to obtain ash, dissolving the ash in distilled water, refluxing, cooling the solution, and filtering to obtain a faint yellow solution which is the suaedasalsa extract liquor; sequentially adding 1mmol of aryl halide, 1.1mmol of arylboronic acid, 0.001mmol to 0.01mmol of a catalyst and 4ml of the suaeda salsa extract liquor into a round-bottom flask,stirring at 100 DEG C to react for 2 hours, cooling the reactant to room temperature, filtering, mixing the obtained filter residue with a palladium catalyst to obtain a mixture; and dissolving the mixture in ethyl acetate, filtering to remove the palladium catalyst, and drying the filtrate by distillation to obtain the biphenyl compound. According to the scheme, a phosphine ligand, alkali and anadditive do not need to be added, a Suzuki reaction system with biomass extract as a reaction medium is adopted, and a green, simple, convenient and efficient method is provided for synthesizing biphenyl compounds.
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Paragraph 0037-0038
(2020/06/30)
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- Palladium(II) complexes comprising naphthylamine and biphenylamine based Schiff base ligands: Synthesis, structure and catalytic activity in Suzuki coupling reactions
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New palladium(II) Schiff base complexes of the general formula [Pd(L1?6)2] [L1 = N-(Naphthyl)-salicylaldimine (1), L2 = N-(Naphthyl)-methoxysalicylaldimine (2), L3 = N-(Biphenyl)-salicylaldimine (3), L4 = N-(Biphenyl)-methoxysalicylaldimine (4), L5 = N-(Naphthyl)-2-hydroxy-1-naphthaldimine (5), L6 = N-(Biphenyl)-2-hydroxy-1-naphthaldimine (6)] 1–6 have been synthesized by the reaction of [Pd(OAc)2] with bidentate Schiff base ligands. The palladium(II) complexes were fully characterized by analytical, spectral (FT?IR, UV–Vis, 1H NMR & 13C NMR) methods. The molecular structure of the one of the complexes [Pd(L1)2] (6) was confirmed by single crystal X?ray diffraction methods. Further, the new palladium(II) complexes were tested as catalyst for Suzuki-Miyaura coupling reactions and exhibits very good catalytic activity.
- Balasubramani, Kasturi,Kaleeswaran, Dhananjayan,Nagalakshmi, Veerasamy,Premkumar, Muniyappan,Sathya, Munusamy,Venkatachalam, Galmari
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- Green synthesis method of aromatic acid
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The invention discloses a green synthesis method of aromatic acid. Nickel-catalyzed carbonyl insertion is carried out on aryl iodine in the presence of formate, acid anhydride, a phosphine ligand andan organic solvent by using a nickel catalyst to obtain the aromatic acid. Efficient catalytic conversion is realized by utilizing the cheap nickel catalyst, the reaction conditions are mild, and theoperation is simple.
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Paragraph 0048-0122; 0212-0216; 0271-0272
(2020/05/01)
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- Magnesiation of Aryl Fluorides Catalyzed by a Rhodium-Aluminum Complex
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We report the magnesiation of aryl fluorides catalyzed by an Al-Rh heterobimetallic complex. We show that the complex is highly reactive to cleave the C-F bonds across the polarized Al-Rh bond under mild conditions. The reaction allows the use of an easy-to-handle magnesium powder to generate a range of arylmagnesium reagents from aryl fluorides, which are conventionally inert to such metalation compared with other aryl halides.
- Fujii, Ikuya,Semba, Kazuhiko,Li, Qiao-Zhi,Sakaki, Shigeyoshi,Nakao, Yoshiaki
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supporting information
p. 11647 - 11652
(2020/08/06)
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