- Tunable electrochemical switches based on ultrathin organic films
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We have performed electroreduction of bisthienyl aminobenzene and thienyl aminobenzene diazonium salts on glassy carbon and polycrystalline gold and generated ultrathin organic films. This method allows covalent bonding between the corresponding aromatic
- Fave, Claire,Leroux, Yann,Trippe, Gaelle,Randriamahazaka, Hyacinte,Noel, Vincent,Lacroix, Jean-Christophe
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Read Online
- Triphenylamine derivatives and the lithium-ion capture of [3.3]cyclophane used in organic dye-sensitized solar cells
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Four novel organic dyes (H-1, H-2, H-3, H-4) containing phenyl-thiophenyl-thiophenyl as a bridge unit were synthesized and effectively used for the fabrication of dye-sensitized solar cells (DSSCs). In both compounds, a triarylamine moiety and cyanoacryli
- Chiu, Yu-Hsiang,Shibahara, Masahiko,Huang, Rui-Yu,Watanabe, Motonori,Wang, Zhong-Sheng,Hsiao, Yu-Jen,Chang, Bo-Fong,Chiang, Ting-Hsuan,Chang, Yuan Jay
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Read Online
- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- Identification of Piperidine-3-carboxamide Derivatives Inducing Senescence-like Phenotype with Antimelanoma Activities
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This study evaluated the potential use of senescence-inducing small molecules in the treatment of melanoma. We screened commercially available small-molecule libraries with high-throughput screening and high-content screening image-based technology. Our findings showed an initial hit with the embedded N-arylpiperidine-3-carboxamide scaffold-induced senescence-like phenotypic changes in human melanoma A375 cells without serious cytotoxicity against normal cells. A focused library containing diversely modified analogues were constructed and examined to evaluate the structure-activity relationship of N-arylpiperidine-3-carboxamide derivatives starting from hit 1. This work identified a novel compound with remarkable antiproliferative activity in vitro and demonstrated the key structural moieties within.
- Oh, Sangmi,Kwon, Do Yoon,Choi, Inhee,Kim, Young Mi,Lee, Ji Young,Ryu, Jiyoung,Jeong, Hangyeol,Kim, Myung Jin,Song, Rita
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p. 563 - 571
(2021/05/06)
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- UiO-66 microcrystals catalyzed direct arylation of enol acetates and heteroarenes with aryl diazonium salts in water
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UiO-66 is a classic Metal–organic framework (MOF) that constructed by zirconium cations and terephthalate with high chemical and thermal stability. Using pristine UiO-66 nanocrystals as the catalysts, the carbon–carbon bond formation based on denitrogenat
- Sun, Zhong-Hua,Chen, Wang,Qian, Bing-Bing,Wang, Liang,Yu, Binxun,Chen, Qun,He, Ming-Yang,Zhang, Zhi-Hui
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- Modular and Selective Arylation of Aryl Germanes (C?GeEt3) over C?Bpin, C?SiR3 and Halogens Enabled by Light-Activated Gold Catalysis
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Selective C (Formula presented.) –C (Formula presented.) couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe3, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings.
- Dahiya, Amit,Fricke, Christoph,Funes-Ardoiz, Ignacio,Gevondian, Avetik G.,Schoenebeck, Franziska,Sherborne, Grant J.
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supporting information
p. 15543 - 15548
(2020/06/22)
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- Black phosphorus as a metal-free, visible-light-active heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes
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Black phosphorus (BP) is for the first time employed as a metal-free, heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes with aryl diazonium salts. The arylated heteroarenes are obtained in moderate to good yields under visible-light illumination, and the protocol is shown to be applicable for the scale-up synthesis.
- Kalay, Erbay,Kü?ükke?eci, Hüseyin,Kilic, Haydar,Metin, ?nder
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supporting information
p. 5901 - 5904
(2020/06/04)
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- Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
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A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
- Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
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supporting information
p. 2510 - 2515
(2020/04/15)
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- Immobilized Pd on a NHC functionalized metal–organic framework MIL-101(Cr): an efficient heterogeneous catalyst in Suzuki?Miyaura coupling reaction in water
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A novel Pd?NHC functionalized metal–organic framework (MOF) based on MIL-101(Cr) was synthesized and used as an efficient heterogeneous catalyst in the C-C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki?Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd?NHC?MIL-101(Cr) was characterized using some different techniques, including Fourier transform-infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, inductively coupled plasma and elemental analysis. The microscopic techniques showed the discrete octahedron structure of MIL-101(Cr), which is also stable after chemical modification process to prepare the catalyst system. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the structure of the catalyst, while no reducing agent was used. It seems that the NHC groups and imidazolium moieties in the structure of the MOF can reduce Pd (II) to Pd (0) species. This modified MOF substrate can also prevent aggregation of Pd nanoparticles, resulting in high stability of them in organic transformation. The Pd?NHC?MIL-101(Cr) catalyst system could be simply extracted from the reaction mixture, providing an efficient synthetic method for the synthesis of biaryls derivatives using the aforementioned coupling reaction. The Pd?NHC?MIL-101(Cr) catalyst could be recycled in this organic reaction with almost consistent catalytic efficiency.
- Khalafi-Nezhad, Ali,Niknam, Esmaeil,Panahi, Farhad
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- Suzuki-Miyaura Cross-Couplings under Acidic Conditions
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Suzuki-Miyaura reactions with Pd(PPh 3) 4 have been carried out using lithium N -phenylsydnone-4-carboxylate as additive, which gave best yields at pH 5.7 in a mixture of acetic acid, water, and sodium carbonate. Reaction parameters such as the Pd source, the solvent, reaction time and temperature, acid, base and carboxylate have been varied and some representative examples of the Suzuki-Miyaura reaction have been examined.
- Freese, Tyll,Kahnert, Sean-Ray,Lücke, Ana-Luiza,Mummel, Sebastian,Pruschinski, Lucas,Schmidt, Andreas
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p. 882 - 892
(2020/03/13)
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- COMPOUNDS AND METHODS TO ATTENUATE TUMOR PROGRESSION AND METASTASIS
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This invention relates to certain compounds or pharmaceutically acceptable salts thereof, and for the use of the compounds to treat cancer. In another aspect, the disclosure relates to a pharmaceutical composition comprising a compound of Formula (1), For
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Paragraph 0264-0265
(2020/05/28)
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- A facile synthesis of mesoporous graphitic carbon nitride supported palladium nanoparticles as highly effective and reusable catalysts for Stille coupling reactions under mild conditions
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The development of a Stille coupling protocol that is operable under moderate conditions without using a base is highly required for the synthetic organic chemistry community, which requires an efficient nanocatalyst. In this respect, addressed herein is a facile one-pot synthesis of mesoporous graphitic carbon nitride (mpg-CN) supported Pd NPs, denoted as mpg-CN/Pd hereafter, and investigation of their catalytic activity in Stille cross-coupling reactions for the first time. It has been demonstrated that mpg-CN nanosheets can serve as not only a support material but also a stabilizer for the generation of 4.5 nm Pd NPs. The ecofriendly generated heterogeneous nanocatalyst was characterized by TEM, XRD, XPS, BET surface area and ICP-MS analysis. The mpg-CN/Pd nanocatalysts showed high activity in the Stille coupling reaction of a variety of electron-deficient and electron-rich aryl iodides/bromides and two different organostannanes with a wide substrate scope to afford the corresponding biaryls without using any bases and additional ligands under relatively mild conditions. The catalyst can be easily recovered from the reaction medium by centrifugation. It can be reused at least 5 times without any loss of activity.
- Cetin, Sultan,Kalay, Erbay,Kolemen, Safacan,Metin, ?nder
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p. 6714 - 6723
(2020/05/16)
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- Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
- Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
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p. 289 - 299
(2019/01/10)
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- Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
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Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
- Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 4364 - 4369
(2019/05/10)
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- Redox reactions of small organic molecules using ball milling and piezoelectric materials
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Over the past decade, photoredox catalysis has harnessed light energy to accelerate bond-forming reactions. We postulated that a complementary method for the redox-activation of small organic molecules in response to applied mechanical energy could be dev
- Kubota, Koji,Pang, Yadong,Miura, Akira,Ito, Hajime
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p. 1500 - 1504
(2020/01/08)
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- C–H Arylation of N-Heteroarenes under Metal-Free Conditions and its Application towards the Synthesis of Pentabromo- and Pentachloropseudilins
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Herein, we are reporting metal-free conditions for radical initiation and direct C–H arylation of N-heteroarenes. Starting from aniline, the corresponding arenediazonium salt generated in situ is reduced to an aryl radical in the presence of chloropromazine hydrochloride, a new reagent for this application. The optimized procedures are mild, operationally simple, and are working successfully with more diverse substrates in comparison to reported methods. The optimized method is also employed for the synthesis of marine natural products Pentabromo- and Pentachloropseudilins (PBP/PCP). In the present study, we also validated the potential of the Pentachloropseudilin (PCP), thus synthesized, for inhibition of Myosin1 function in mammalian cells and confirmed that PCP phenocopies Myosin1c depletion in cells.
- Kumar, Mukesh,Sharma, Shweta,Sil, Parijat,Kushwaha, Manoj,Mayor, Satyajit,Vishwakarma, Ram A.,Singh, Parvinder Pal
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supporting information
p. 3591 - 3598
(2019/06/20)
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- Novel substituted benzoyl compound and its pharmaceutically acceptable salt and preparation method and application (by machine translation)
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The invention relates to the general formula I shown novel substituted benzoyl compound and its pharmaceutically acceptable salt and preparation method and application. The invention also provides pharmaceutical compositions containing them, in vitro and in vivo anti-tumor effect results and acute toxicity study, the obtained anti-tumor drug model substituted benzoyl compound, has more excellent anti-tumor activity and safety, can be in the treatment of leukemia, lung cancer, colon cancer, ovarian cancer and renal carcinoma tumor in the application, so that the therapeutic window, so in the medical field as antitumor agents in the very application value. (by machine translation)
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Paragraph 0180-0181; 0183-0184
(2019/11/13)
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- Small-Molecule Covalent Modification of Conserved Cysteine Leads to Allosteric Inhibition of the TEAD?Yap Protein-Protein Interaction
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The Hippo pathway coordinates extracellular signals onto the control of tissue homeostasis and organ size. Hippo signaling primarily regulates the ability of Yap1 to bind and co-activate TEA domain (TEAD) transcription factors. Yap1 tightly binds to TEAD4
- Bum-Erdene, Khuchtumur,Zhou, Donghui,Gonzalez-Gutierrez, Giovanni,Ghozayel, Mona K.,Si, Yubing,Xu, David,Shannon, Harlan E.,Bailey, Barbara J.,Corson, Timothy W.,Pollok, Karen E.,Wells, Clark D.,Meroueh, Samy O.
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p. 378 - 13,389
(2019/03/19)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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supporting information
p. 17651 - 17655
(2018/11/10)
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- C-H arylation reactions through aniline activation catalysed by a PANI-g-C3N4-TiO2 composite under visible light in aqueous medium
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A PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for radical C-H arylation reactions. The arylation process involved coupling of in situ generated aryl diazonium salts from aniline with heteroarenes, enol acetates or benzoquinones under visible light in aqueous medium or pure water. A broad range of substrates survived the reaction conditions to provide the desired products in moderate to good yields. Scale-up (10 mmol) synthesis was also achieved. This semiconductor photocatalyst showed good photocatalytic performance and stability. Recycle studies showed that this composite could be readily recovered and a slight decrease in the catalytic activity was observed after ten consecutive runs.
- Wang, Liang,Shen, Jun,Yang, Sen,Liu, Wenjie,Chen, Qun,He, Mingyang
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supporting information
p. 1290 - 1296
(2018/03/26)
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- Merging visible-light photoredox and micellar catalysis: Arylation reactions with anilines nitrosated in situ
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An aqueous photocatalytic system was designed by merging visible-light photoredox catalysis with micellar catalysis. Eosin B, an organic dye, was utilized as the photocatalyst, and Triton X-100 was employed as the surfactant; both are inexpensive and commercially available. This clean and energy-saving catalytic system enables photocatalytic reactions of the diazonium ion generated in situ to proceed smoothly in water without any co-solvents or additives at room temperature.
- Bu, Mei-Jie,Lu, Guo-Ping,Jiang, Jianzhong,Cai, Chun
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p. 3728 - 3732
(2018/08/12)
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- A new face of phenalenyl-based radicals in the transition metal-free C-H arylation of heteroarenes at room temperature: Trapping the radical initiator: Via C-C σ-bond formation
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The radical-mediated transition metal-free approach for the direct C-H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively stable odd alternant hydrocarbon-based phenalenyl (PLY) radical. In this study, the first transition metal-free catalyzed direct C-H arylation of a variety of heteroarenes such as azoles, furan, thiophene and pyridine at room temperature has been reported using a phenalenyl-based radical without employing any photoactivation step. This protocol has been successfully applied to the gram scale synthesis of core moieties of bioactive molecules. The phenalenyl-based radical initiator has been characterized crystallographically by trapping it via the formation of a C-C σ-bond between the phenalenyl radical and solvent-based radical species.
- Ahmed, Jasimuddin,Sreejyothi,Vijaykumar, Gonela,Jose, Anex,Raj, Manthan,Mandal, Swadhin K.
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p. 7798 - 7806
(2017/10/30)
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- Porphyrin-Catalyzed Photochemical C–H Arylation of Heteroarenes
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Organic dyes are a promising class of photoredox catalysts and offer a meaningful alternative to broadly applied Ru and Ir complexes. We found that porphyrins with tuned physicochemical properties, by tailoring various substituents at the periphery of the
- Rybicka-Jasińska, Katarzyna,K?nig, Burkhard,Gryko, Dorota
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supporting information
p. 2104 - 2107
(2017/04/24)
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- A g-C3N4/rGO nanocomposite as a highly efficient metal-free photocatalyst for direct C-H arylation under visible light irradiation
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Visible light mediated photoredox arylations can proceed under very mild conditions and have therefore become attractive. Nowadays, various metal nanomaterials and metal complexes have been developed as photocatalysts for direct arylation of heteroaromatics. These photocatalysts, however, still suffer from corrosion, high cost, aggregation or poor stability. We report the design and fabrication of a g-C3N4/rGO nanocomposite and demonstrate its excellent activity, high apparent quantum efficiency, and recyclability to catalyze the metal free direct arylation of heteroaromatics under visible light at room temperature. Moreover, the g-C3N4/rGO catalyst can be reused more than five times without significant loss of activity, confirming this catalyst's excellent stability. The present strategy to fabricate a metal-free g-C3N4/rGO nanocomposite for direct C-H arylation open a new avenue towards replacing metal-based catalysts in fine organic synthesis.
- Cai, Xiaohui,Liu, Hanwen,Zhi, Lihua,Wen, Huang,Yu, Ailing,Li, Lianhua,Chen, Fengjuan,Wang, Baodui
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p. 46132 - 46138
(2017/10/10)
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- End-Capping Groups for Small-Molecule Organic Semiconducting Materials: Synthetic Investigation and Photovoltaic Applications through Direct C–H (Hetero)arylation
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A Pd-catalyzed C–H (hetero)arylation methodology has been optimized for the efficient synthesis of various useful end-capping groups that are widely applied in small-molecule optoelectronic materials. We report herein the synthesis of a broad scope of target molecules ranging from donor-type through acceptor-type to hybrid-type end-capping groups. To demonstrate their application in dye-sensitized solar cells, we have designed two new D–A–π–A′-type organic sensitizers (CYL-3 and CYL-4), which were synthesized in a step-economic manner by sequential C–H arylations using the facilely obtained end-capping groups. The devices based on CYL-3 and CYL-4 give Vocvalues of 0.67–0.71 V, Jscvalues of 10.07–11.63 mA cm–2, and FF values of 70.6–72.9 %, which correspond to overall power conversion efficiencies of 4.76–6.02 %. This work is expected to become a practical synthetic alternative allowing materials scientists to access small-molecule organic materials in fewer synthetic transformations.
- Lu, Te-Jui,Lin, Po-Han,Lee, Kun-Mu,Liu, Ching-Yuan
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p. 111 - 123
(2017/01/14)
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- Iodine-Catalyzed Synthesis of Chalcogenophenes by the Reaction of 1,3-Dienyl Bromides and Potassium Selenocyanate/Potassium Sulfide (KSeCN/K2S)
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The methods available for the synthesis of chalcogenophenes, in general, are associated with drawbacks of harsh conditions, use of costly metals, broad applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal-free iodine-catalyzed reaction of aryl-susbstituted 1,3-dienyl bromides with potassium selenocyanate/potassium sulfide (KSeCN/K2S) leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. Several diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2-(4-chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one-pot essentially it proceeds in two steps involving a selenocyanate/thiolate intermediate leading to the selenophene/thiophene. The simple operation, use of inexpensive reagents and a metal-free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes. (Figure presented.).
- Maity, Pintu,Ranu, Brindaban C.
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p. 4369 - 4378
(2017/12/26)
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- Polyaniline-Induced Arylation with Arenediazonium Salts Derived from Anilines
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A catalytic amount of a reduced form of polyaniline (a redox-active π-conjugated polymer) was found to induce C?H direct arylation of (hetero)arenes with arenediazonium salts prepared from anilines with methanesulfonic acid (MeSO3H) and tert-butyl nitrite (tBuONO). The difficult part of this method is the coexistence of an oxidant and a reductant in this sequential diazotization and arylation system; diazotization requires weak oxidants such as alkyl nitrites, whereas the arylation is induced by a reductant. This was achieved by the careful control of the amount of tBuONO (1.0 equivalent) for the diazotization step, and sequential arylation using 5 mol % of the polyaniline. The reaction took place under mild conditions without any metals or strong bases at room temperature, and the amino group is a formal leaving group. The scope of the substrates demonstrates the versatility in the combination of anilines with a variety of functional groups and several (hetero)arenes. Two-directional arylation for the synthesis of an unsymmetrical 1,4-diarylated (furyl and pyrrolyl groups) benzene was achieved, using mono-Boc-protected 1,4-phenylenediamine as a substrate. This shows potential for the synthesis of more complicated oligoarene compounds.
- Hata, Dai,Moriuchi, Toshiyuki,Hirao, Toshikazu,Amaya, Toru
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supporting information
p. 7703 - 7709
(2017/06/06)
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- Photo-oxidative Cross-Dehydrogenative Coupling-Type Reaction of Thiophenes with α-Position of Carbonyls Using a Catalytic Amount of Molecular Iodine
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A metal-free photo-oxidative intermolecular C-H/C-H coupling reaction of thiophenes is demonstrated with carbonyls using a catalytic amount of molecular iodine. In this system, molecular oxygen in the air acted as a terminal oxidant to regenerate molecular iodine. A mechanistic study was also performed.
- Sudo, Yusuke,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 1610 - 1613
(2017/04/13)
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- Direct C–H Arylation of Heteroarenes with Aryl Chlorides by Using an Abnormal N-Heterocyclic-Carbene–Palladium Catalyst
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Herein, we report a versatile catalytic system for the direct C–H arylation of heteroarenes with activated aryl chloride substrates. The catalyst works successfully for a variety of heteroarenes and aryl chloride coupling partners under very low catalyst-loading conditions. We have successfully performed the direct C–H arylations of 1-methylpyrrole, 1-methylindole, furan, thiophene, furfural, and N-benzyl-1,2,3-triazole with aryl chloride partners in good yields without the use of any additives. Furthermore, we used this catalytic process to develop a one-pot synthetic protocol for the muscle relaxant dantrolene on a gram scale. Additionally, the present catalytic system can be used to perform consecutive arylations in one pot.
- Ahmed, Jasimuddin,Sau, Samaresh Chandra,Sreejyothi,Hota, Pradip Kumar,Vardhanapu, Pavan K.,Vijaykumar, Gonela,Mandal, Swadhin K.
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supporting information
p. 1004 - 1011
(2017/02/15)
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- Visible-Light-Promoted Arylation Reactions Photocatalyzed by Bismuth(III) Oxide
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Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol-%), this cheap and nontoxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the process admits straightforward scale-up (10 mmol; 1 mol-% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 also catalyzed the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes.
- Buglioni, Laura,Riente, Paola,Palomares, Emilio,Pericàs, Miquel A.
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supporting information
p. 6986 - 6990
(2017/12/26)
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- Blue light mediated C-H arylation of heteroarenes using TiO2 as an immobilized photocatalyst in a continuous-flow microreactor
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Titanium dioxide was applied as an immobilized photocatalyst in a microstructured falling film reactor for the continuous-flow C-H arylation of heteroarenes with aryldiazonium salts as the starting material. Detailed investigations of the catalyst and a successful long-term run proved its excellent usability for this process. Very good yields up to 99% were achieved with broad substrate scope and were compared with batch synthesis. The transfer to the continuous-flow mode revealed an impressive boost in reactor performance solely resulting from the improved irradiation and contact of the catalyst, substrate and light.
- Fabry, David C.,Ho, Yee Ann,Zapf, Ralf,Tremel, Wolfgang,Panth?fer, Martin,Rueping, Magnus,Rehm, Thomas H.
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supporting information
p. 1911 - 1918
(2017/06/09)
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- Gram-scale synthesis of aligned C3N4-polypyrrole heterojunction aerogels with tunable band structures as efficient visible and near infrared light-driven metal-free photocatalysts
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The assembly of aligned porous materials from simple building blocks is of widespread interest for engineering materials with enhanced and synergistic properties. To date, however, how to develop 3D heterojunction aerogels with aligned porosity based on 2D semiconductor materials and 1D conducting polymers for solar energy conversion in the visible and near-infrared (NIR) light region remains a significant challenge. Here a new class of gram-scale 3D aligned heterojunction aerogels of polypyrrole (PPy)/C3N4 nanosheets (NSs) were designed and synthesized by directional freezing of polypyrrole (PPy)/polyvinyl alcohol (PVA) and C3N4 NS aqueous suspension. The synthesis of aligned C3N4-PPy heterojunction aerogels can be achieved on a large scale. The formed aerogel expresses stable and uniform dispersion of the two building blocks, long-range channel aligned structures along the whole monolithic sample, and additional special complementary optical properties between PPy and C3N4 NSs. Based on the above unique structure and optical properties, this novel metal-free heterojunction aerogel exhibits excellent photocatalytic activity and long-term stability for direct arylation of heteroaromatics under visible and near infrared (NIR) light irradiation at room temperature, far exceeding those of the single- and two-component systems. Our work therefore not only provides a new approach to obtain aligned heterojunction aerogels based on metal free semiconductors but also paves a way to develop gram-scale aerogels as a new type of highly efficient visible and NIR light induced heterogeneous photocatalyst.
- Liu, Jian,Wang, Hao,Bai, Jinwei,Li, Tianrong,Yang, Yanmei,Peng, Yong,Wang, Baodui
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p. 24920 - 24928
(2017/12/15)
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- Interface coassembly of mesoporous MoS2 based-frameworks for enhanced near-infrared light driven photocatalysis
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The three-dimensional porous Fe3O4@Cu2-xS-MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.
- Zhi, Lihua,Zhang, Haoli,Yang, Zhengyin,Liu, Weisheng,Wang, Baodui
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supporting information
p. 6431 - 6434
(2016/05/24)
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- Radical C-H arylations of (hetero)arenes catalysed by gallic acid
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Gallic acid efficiently catalyses radical arylations in water-acetone at room temperature. This methodology proved to be versatile and scalable. Therefore, it constitutes a greener alternative to arylation. Moreover, considering that gallic acid is an abundant vegetable tannin, this work also unleashes an alternative method for the reutilisation of bio-wastes.
- Perretti, Marcelle D.,Monzón, Diego M.,Crisóstomo, Fernando P.,Martín, Víctor S.,Carrillo, Romen
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supporting information
p. 9036 - 9039
(2016/07/21)
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- Unexpected dual role of titanium dioxide in the visible light heterogeneous catalyzed C-H arylation of heteroarenes
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The direct arylation of heteroaromatics with an easily accessible and recyclable, heterogeneous TiO2 catalyst and visible light was developed. Electron-rich as well as electron-poor heteroarenes could be applied in this transformation, and the corresponding products were isolated in very good yields. Azoethers were detected as reactive intermediates, and the unexpected role of TiO2 in their formation as well as reaction was established.
- Zoller, Jochen,Fabry, David C.,Rueping, Magnus
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p. 3900 - 3904
(2015/06/16)
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- A family of low molecular-weight, organic catalysts for reductive C-C bond formation
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Hydrazines form a new family of low molecular-weight reducing agents for diazonium salts. Using only small amounts of hydrazine catalyst, the coupling of diazonium salts to a variety of reactive partners has been achieved, without the requirement for either metal adjuvants or irradiation with visible or ultraviolet light. The generality of the concept proposed herein as well as its advantages in the preparative scale is outlined and discussed.
- Shaaban, Saad,Jolit, Ana?s,Petkova, Desislava,Maulide, Nuno
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supporting information
p. 13902 - 13905
(2015/09/15)
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- Polyaniline-Induced C-H Arylation of Arenes with Arenediazonium Salts
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A reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg-Bachmann reaction) to give the cross-coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron-poor arenediazonium salt with an electron-rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one-electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross-coupling reaction to occur. This reaction proceeds under metal-free conditions and with no need for photonic activation.
- Amaya, Toru,Hata, Dai,Moriuchi, Toshiyuki,Hirao, Toshikazu
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p. 16427 - 16433
(2015/11/10)
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- In situ-generated nano-palladium-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates at room temperature
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A mild and simple protocol is described for the palladium-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates in aqueous ethanol at room temperature. Palladium nanoparticles are generated in situ in the reaction and demonstrate high activity towards a wide range of aryl bromides and potassium aryltrifluoroborates, providing biphenyls in good to excellent yields. Interestingly, only 1 equiv of K2CO3 is used in this catalytic system. Moreover, the key biaryl intermediate of 2-cyano-4′-methylbiphenyl within valsartan is prepared in a 95% yield after 2 h.
- Liu, Chun,Li, Xinmin,Gao, Zhanming,Wang, Xinnan,Jin, Zilin
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supporting information
p. 3954 - 3959
(2015/06/02)
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- Light-Induced C-H Arylation of (Hetero)arenes by in Situ Generated Diazo Anhydrides
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Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time.
- Cantillo, David,Mateos, Carlos,Rincon, Juan A.,De Frutos, Oscar,Kappe, C. Oliver
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supporting information
p. 12894 - 12898
(2015/09/07)
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- Immobilized Pd on magnetic nanoparticles bearing proline as a highly efficient and retrievable Suzuki-Miyaura catalyst in aqueous media
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A magnetically retrievable nanocatalyst was evaluated for a microwave assisted Suzuki-Miyaura reaction in aqueous media. Excellent yields and conversions were obtained with low Pd loadings (down to 0.01 mol% Pd). It was stable up to 6 months in water under aerobic conditions and efficiency remained unaltered even after 7 repeated cycles. This journal is
- Nehlig,Waggeh,Millot,Lalatonne,Motte,Gunin
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supporting information
p. 501 - 505
(2015/02/19)
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- Palladacycles derived from arylphosphinamides for mild Suzuki-Miyaura cross-couplings
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We present a type of palladacyclic complexes derived from arylphosphinamides which can be used as efficient and versatile precatalysts for mild Suzuki-Miyaura cross-coupling. With the presence of 1.0 mol% of palladacycles, a wide variety of aryl bromides and boronic acids could be coupled very efficiently at ambient temperature and under air atmosphere without the need of external supporting ligands. Moreover, the mild conditions also allow for smooth coupling of electron-deficient, i.e., the less stable aryl triflates. In addition to the highly catalytic activity, the palladacyclic complexes can be very easily prepared through a two-step procedure from the readily affordable diphenyl-phosphinic chloride and exhibit excellent stability toward air and moisture. Due to these prominent properties, the new palladacycles would find practical use in Suzuki-Miyaura couplings.
- Wu, Guo-Jie,Han, Fu-She,Zhao, Yu-Long
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p. 69776 - 69781
(2015/09/01)
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- Synthesis of heteroaryl compounds through cross-coupling reaction of aryl bromides or benzyl halides with thienyl and pyridyl aluminum reagents
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An efficient method for synthesis of useful biaryl building blocks containing 2-thienyl, 3-thienyl, 2-pyridyl, and 3-pyridyl moieties was provided through cross-coupling reactions of aryl bromides or benzyl halides with heteroaryl aluminum reagents in the presence of Pd(OAc)2 and (o-tolyl)3P. The coupling reaction also worked efficiently with heteroaryl bromides affording series of heterobiaryl compounds. The reaction of phenylbromide with in situ prepared 3-pyridyl aluminum was demonstrated to afford the product 8a in high yield. Additionally, the catalytic system was also suited well for the coupling reaction of benzyl halides with pyridyl aluminum reagents to afford series of pyridyl-arylmethane.
- Chen, Xu,Zhou, Lingmin,Li, Yimei,Xie, Tao,Zhou, Shuangliu
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p. 230 - 239
(2014/01/17)
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- Ascorbic acid as an initiator for the direct C-H arylation of (hetero)arenes with anilines nitrosated in situ
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Ascorbic acid (vitaminC) has been used as a radical initiator in a metal-free direct C-H arylation of (hetero)arenes. Starting from an aniline, the corresponding arenediazonium ion is generated in situ and immediately reduced by vitaminC to an aryl radical that undergoes a homolytic aromatic substitution with a (hetero)arene. Notably, neither heating nor irradiation is required. This procedure is mild, operationally simple, and constitutes a greener approach to arylation. Copyright
- Crisostomo, Fernando Pinacho,Martin, Tomas,Carrillo, Romen
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supporting information
p. 2181 - 2185
(2014/03/21)
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- N-picolinamides as ligands for Ullmann-type homocoupling reactions
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The use of N-phenylpicolinamide (NPPA) as a ligand in Ullmann-type homocoupling reactions of aryl iodides and bromides in common solvents, such as DMF and MeCN has been successfully demonstrated at room temperature. In addition, this work provided the first example of the homocoupling of an aryl chloride at 82 °C, which is a relatively low temperature when compared to regular Ullmann reaction temperatures. Also, NPPA was successfully employed in base-and heat free Suzuki reactions, including electron rich and poor aryl halides with heteroarylboronic acids in moderate yields.
- Damkaci, Fehmi,Altay, Esra,Waldron, Matthew,Knopp, Michael A.,Snow, David,Massaro, Nicholas
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supporting information
p. 690 - 693
(2014/01/23)
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- Iodo-Bodipys as visible-light-absorbing dual-functional photoredox catalysts for preparation of highly functionalized organic compounds by formation of C-C bonds via reductive and oxidative quenching catalytic mechanisms
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Iodo-Bodipys were used as organic catalysts for three different photoredox catalytic organic reactions, i.e. the aza-Henry reaction of tetrahydroisoquinoline, oxidation/[3 + 2] cycloaddition/oxidative aromatization tandem reaction between tetrahydroisoquinolines and maleimides, and C-H arylation of heteroarenes with diazonium salts. The organic photocatalysts act as either electron acceptors (reductive quenching) or electron donors (oxidative quenching) in the single electron transfer (SET) of the catalytic cycles. Different from the widely used Ru(bpy)3[PF6]2, Ir(ppy)3, or halo-xanthane photocatalysts (Eosin Y or Rose Bengal), the new organic photocatalysts show strong absorption of visible light and long-lived triplet excited states, which are beneficial for SET, a crucial step for photoredox catalytic organic reactions. Moreover, the molecular structures of the new photocatalysts can be easily modified, as a result the absorption wavelength of the photocatalysts was readily tuned from 529 nm to 630 nm. The three different types of organic reactions are accelerated with the new organic photocatalysts (typical reaction times 1-2 h) compared to that catalyzed by Ru(bpy)3[PF6]2 or Ir(ppy)3 (reaction time: 12-72 h). The C-H arylation of thiophene with phenyl diazonium salts was used to prepare new Bodipy derivatives that show large Stokes shift. Our results are useful for designing of new organic catalysts for photoredox catalytic organic reactions to prepare highly functionalize organic compounds.
- Huang, Ling,Zhao, Jianzhang
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p. 23377 - 23388
(2013/11/19)
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- Sensitized photografting of diazonium salts by visible light.
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Visible irradiation of a gold surface dipped into a solution of diversely substituted aryldiazonium salts in the presence of a photosensitizer (Ru(bipy)32+ or eosinY) leads to a modification of the surface by attached aryl groups. A grafted nanometer thick polyphenylene film is obtained. The reaction is extended to a polyvinylchloride (PVC) surface. The mechanism proposed for the formation of this film involves the formation of an aryl radical that reacts with the surface and then with the first grafted aryl group. The film is characterized by infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), water contact angles, and ellipsometry.
- Bouriga, Meriem,Chehimi, Mohamed M.,Combellas, Catherine,Decorse, Philippe,Kanoufi, Frederic,Deronzier, Alain,Pinson, Jean
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- Copper-catalyzed Hiyama coupling of (hetero)aryltriethoxysilanes with (hetero)aryl iodides
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A CuI-catalyzed Hiyama coupling was achieved, which proceeds in the absence of an ancillary ligand for aryl-heteroaryl and heteroaryl-heteroaryl couplings. A P,N-ligand is required to obtain the best product yields for aryl-aryl couplings. In addition to facilitating transmetalation, CsF is also found to function as a stabilizer of the [CuAr] species, potentially generated as an intermediate after transmetalation of aryltriethoxysilanes with Cu I-catalysts in the absence of ancillary ligands.
- Gurung, Santosh K.,Thapa, Surendra,Vangala, Adarsh S.,Giri, Ramesh
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supporting information
p. 5378 - 5381
(2013/11/06)
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- Metal-free, visible-light-mediated direct C-H arylation of heteroarenes with aryl diazonium salts
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Visible light along with 1 mol % eosin Y catalyzes the direct C-H bond arylation of heteroarenes with aryl diazonium salts by a photoredox process. We have investigated the scope of the reaction for several aryl diazonium salts and heteroarenes. The general and easy procedure provides a transition-metal-free alternative for the formation of aryl-heteroaryl bonds.
- Hari, Durga Prasad,Schroll, Peter,Koenig, Burkhard
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supporting information; experimental part
p. 2958 - 2961
(2012/04/04)
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- Design and synthesis of boronic acid inhibitors of endothelial lipase
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Endothelial lipase (EL) and lipoprotein lipase (LPL) are homologous lipases that act on plasma lipoproteins. EL is predominantly a phospholipase and appears to be a key regulator of plasma HDL-C. LPL is mainly a triglyceride lipase regulating (V)LDL levels. The existing biological data indicate that inhibitors selective for EL over LPL should have anti-atherogenic activity, mainly through increasing plasma HDL-C levels. We report here the synthesis of alkyl, aryl, or acyl-substituted phenylboronic acids that inhibit EL. Many of the inhibitors evaluated proved to be nearly equally potent against both EL and LPL, but several exhibited moderate to good selectivity for EL.
- O'Connell, Daniel P.,Leblanc, Daniel F.,Cromley, Debra,Billheimer, Jeffrey,Rader, Daniel J.,Bachovchin, William W.
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scheme or table
p. 1397 - 1401
(2012/03/26)
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- A highly active catalytic system for Suzuki-Miyaura cross-coupling reactions of aryl and heteroaryl chlorides in water
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An easily available Pd(OAc)2/(2-mesitylindenyl) dicyclohexylphosphine/Me(octyl)3N+Cl-/K 3PO4·3H2O catalytic system was developed and it shows high catalytic activity in the Suzuki-Miyaura cross-coupling reaction of a diverse array of aryl and heteroaryl chlorides in water. Notably, this catalytic system also works with ultra-low loading of the catalyst with high turnover numbers.
- Mao, Shu-Lan,Sun, Yue,Yu, Guang-Ao,Zhao, Cui,Han, Zhi-Jun,Yuan, Jia,Zhu, Xiaolei,Yang, Qihua,Liu, Sheng-Hua
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p. 9410 - 9417
(2013/01/15)
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