- Magnesium and calcium complexes containing biphenyl-based tridentate iminophenolate ligands for ring-opening polymerization of rac -lactide
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A series of racemic 2-[(2′-methoxybiphenyl-2-ylimino)methyl]-4-R 2-6-R1-phenols (L1H-L8H) were reacted with {Mg[N(SiMe3)2]2}2 and Ca[N(SiMe3)2]2·2THF (THF = tetrahydrofuran), respectively, to provide nine heteroleptic magnesium complexes L1-8MgN(SiMe3)2 [R1 = iPr, R2 = H (1a); R1 = tBu, R 2 = Me (2a and 2a·THF); R1 = R2 = tBu (3a); R1 = R2 = CMe2Ph (4a); R1 = CPh3, R2 = tBu (5a); R 1 = 1-piperidinylmethyl, R2 = tBu (6a); R 1 = Cl, R2 = tBu (7a); R1 = Br, R2 = tBu (8a)], two homoleptic calcium complexes (L 2,5)2Ca (2b and 5b), and one heteroleptic calcium complex [(L4)CaN(SiMe3)2·THF] (4b), which have been fully characterized. In the solid state, magnesium complexes 2a and 6a are isostructural, and each possesses a monomeric structure, while magnesium complexes 7a and 8a are dimeric, where the two metal centers are bridged by two phenolate oxygen atoms of the ligands. The coordination geometry around the magnesium center in these complexes can be best described as a distorted tetrahedral geometry. Although bearing the same iminophenoloate ligand, the molecular structures of complexes 2a and 2a·THF are different from each other. In complex 2a·THF, the coordination of one molecule of THF to the magnesium atom leads to dissociation of the methoxy group of the ligand from the metal center. The homoleptic calcium complex 2b has a six-coordinate metal core ligated by all six donor atoms of two iminophenolate ligands. The heteroleptic magnesium complexes 1a-8a and calcium complex 4b proved to be efficient initiators for the ring-opening polymerization of rac-lactide at ambient temperature in THF or at 70 C in toluene, and the polymerizations were better controlled in the presence of 2-propanol. The introduction of a bulky ortho substituent on the phenoxy unit of the ligand resulted in an increase of the catalytic activity of the corresponding metal complex. Microstructure analysis of the resultant poly(rac-lactide) samples via homonuclear-decoupled 1H NMR spectroscopy revealed Pr values ranging from 0.60 to 0.81, which closely depended on the employed catalyst and polymerization conditions.
- Yi, Wei,Ma, Haiyan
-
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Read Online
- Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
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A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
- Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
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supporting information
p. 7150 - 7155
(2021/09/18)
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- Synthesis of 3-aryl-1-phosphinoimidazo[1,5-a]pyridine ligands for use in Suzuki-Miyaura cross-coupling reactions
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3-Aryl-1-phosphinoimidazo[1,5-a]pyridine ligands were synthesized from 2-aminomethylpyridine as the initial substrateviatwo complementary routes. The first synthetic pathway underwent the coupling of 2-aminomethylpyridine with substituted benzoyl chlorides, followed by cyclization, iodination and palladium-catalyzed cross-coupling phosphination reactions sequence to give our phosphorus ligands. In the second route, 2-aminomethylpyridine was cyclized with aryl aldehydes, followed by the iodination and palladium-catalyzed cross-coupling phosphination reactions to yield our phosphorus ligands. The 3-aryl-1-phosphinoimidazo[1,5-a]pyridine ligands were evaluated in palladium-catalyzed sterically-hindered biaryl and heterobiaryl Suzuki-Miyaura cross-coupling reactions.
- Dinh, Long P.,Harris, Nekoda W.,Jacoby, Seth A.,Semsey, Rebecca Y.,Swann, William A.,Tran, Ryan Q.,Williamson, Savannah N.,Yet, Larry
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p. 28347 - 28351
(2021/09/15)
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- Scalable electrochemical synthesis of diaryliodonium salts
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Cyclic and acyclic diaryliodonium are synthesised by anodic oxidation of iodobiaryls and iodoarene/arene mixtures, respectively, in a simple undivided electrolysis cell in MeCN-HFIP-TfOH without any added electrolyte salts. This atom efficient process does not require chemical oxidants and generates no chemical waste. More than 30 cyclic and acyclic diaryliodonium salts with different substitution patterns were prepared in very good to excellent yields. The reaction was scaled-up to 10 mmol scale giving more than four grams of dibenzo[b,d]iodol-5-ium trifluoromethanesulfonate (>95%) in less than three hours. The solvent mixture of the large-scale experiment was recovered (>97%) and recycled several times without significant reduction in yield.
- Elsherbini, Mohamed,Moran, Wesley J.
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supporting information
p. 4706 - 4711
(2021/06/11)
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- Photocatalytic xanthate-based radical addition/cyclization reaction sequence toward 2-biphenyl isocyanides: Synthesis of 6-alkylated phenanthridines
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A photocatalytic xanthate-based radical addition/cyclization reaction cascade toward 2-biphenylisocyanides is described as a practical and modular approach to 6-alkylated phenanthridines. The use of xanthates as radical precursors allowed the synthesis of diversely 6-substituted phenanthridines. Electrophilic radicals derived from nitriles, aromatic and aliphatic ketones, malonates, and amide derivatives, as well as radicals derived from phthalimidomethyl and benzylic derivatives were successfully introduced. The reaction proceeds under mild conditions without a stoichiometric amount of oxidant. Thirty novel phenanthridine scaffolds were synthesized with yields ranging from 24 to 76%.
- López-Mendoza, Pedro,Miranda, Luis D.
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supporting information
p. 3487 - 3491
(2020/05/25)
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- HETEROCYCLIC COMPOUND AND ORGANIC LIGHT EMITTING DEVICE COMPRISING SAME
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The present specification relates to a heterocyclic compound represented by Chemical Formula 1, and an organic light emitting device comprising the same.
- -
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Paragraph 0224-0226
(2020/05/14)
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- Visible-Light-Driven Difluoromethylation of Isocyanides with S-(Difluoromethyl)diarylsulfonium Salt: Access to a Wide Variety of Difluoromethylated Phenanthridines and Isoquinolines
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A highly efficient approach of visible-light-driven radical difluoromethylation of isocyanides to access a wide variety of difluoromethylated phenanthridines and isoquinolines is herein described. Electrophilic S-(difluoromethyl)diarylsulfonium salt proved to be a good difluoromethyl radical precursor under photoredox catalysis. A broad range of isocyanides were tolerated to furnish the corresponding difluoromethylated phenanthridines, isoquinolines, furo[3,2-c]pyridine, and pyrido[3,4-b]indole in moderate to excellent yields under mild conditions. A plausible mechanism was also proposed.
- Chen, Jia-Yi,Li, Xin,Lin, Li-Ting,Liu, Guo-Kai,Qin, Wen-Bing,Wong, Henry N. C.,Xiong, Wei
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p. 10479 - 10487
(2020/09/23)
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- NBE-Controlled Palladium-Catalyzed Interannular Selective C-H Silylation: Access to Divergent Silicon-Containing 1,1′-Biaryl-2-Acetamides
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A novel palladium-catalyzed interannular selective C-H silylation of 1,1′-biaryl-2-acetamides is described. The combination of palladium catalyst with copper oxidant enables meta- or ortho-selective C-H silylation by employing hexamethyldisilane as a trimethylsilyl source, which relies on the control of NBE derivatives as a switch, thus providing straightforward access to divergent silicon-containing 1,1′-biaryl-2-acetamides.
- Li, Wenguang,Chen, Wenqi,Zhou, Bang,Xu, Yankun,Deng, Guobo,Liang, Yun,Yang, Yuan
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supporting information
p. 2718 - 2722
(2019/04/16)
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- Copper-Catalyzed Diphenylation of P(O)-OH Bonds with Cyclic Diaryliodonium Salts
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A copper-catalyzed diphenylation of P(O)?OH bonds with cyclic diaryliodonium salts is described. Valuable 2′-iodo substituted biaryl phosphinic/phosphoric acid esters were obtained in good to excellent yields, which could be further transformed to diversified building blocks for the synthesis of bioactive compounds, pharmaceuticals and functional materials.
- Wang, Gang,Xiong, Biquan,Zhou, Congshan,Liu, Yu,Xu, Weifeng,Yang, Chang-An,Tang, Ke-Wen,Wong, Wai-Yeung
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p. 4365 - 4374
(2019/11/29)
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- Polyfunctional Imidazolium Aryloxide Betaine/Lewis Acid Catalysts as Tools for the Asymmetric Synthesis of Disfavored Diastereomers
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Enzymes are Nature's polyfunctional catalysts tailor-made for specific biochemical synthetic transformations, which often proceed with almost perfect stereocontrol. From a synthetic point of view, artificial catalysts usually offer the advantage of much broader substrate scopes, but stereocontrol is often inferior to that possible with natural enzymes. A particularly difficult synthetic task in asymmetric catalysis is to overwrite a pronounced preference for the formation of an inherently favored diastereomer; this requires a high level of stereocontrol. In this Article, the development of a novel artificial polyfunctional catalyst type is described, in which an imidazolium-aryloxide betaine moiety cooperates with a Lewis acidic metal center (here Cu(II)) within a chiral catalyst framework. This strategy permits for the first time a general, highly enantioselective access to the otherwise rare diastereomer in the direct 1,4-addition of various 1,3-dicarbonyl substrates to β-substituted nitroolefins. The unique stereocontrol by the polyfunctional catalyst system is also demonstrated with the highly stereoselective formation of a third contiguous stereocenter making use of a diastereoselective nitronate protonation employing α,β-disubstituted nitroolefin substrates. Asymmetric 1,4-additions of β-ketoesters to α,β-disubstituted nitroolefins have never been reported before in literature. Combined mechanistic investigations including detailed spectroscopic and density functional theory (DFT) studies suggest that the aryloxide acts as a base to form a Cu(II)-bound enolate, whereas the nitroolefin is activated by H-bonds to the imidazolium unit and the phenolic OH generated during the proton transfer. Detailed kinetic analyses (RPKA, VTNA) suggest that (a) the catalyst is stable during the catalytic reaction, (b) not inhibited by product and (c) the rate-limiting step is most likely the C-C bond formation in agreement with the DFT calculations of the catalytic cycle. The robust catalyst is readily synthesized and recyclable and could also be applied to a cascade cyclization.
- Willig, Felix,Lang, Johannes,Hans, Andreas C.,Ringenberg, Mark R.,Pfeffer, Daniel,Frey, Wolfgang,Peters, René
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supporting information
p. 12029 - 12043
(2019/08/16)
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- Correction to: Polyfunctional Imidazolium Aryloxide Betaine/Lewis Acid Catalysts as Tools for the Asymmetric Synthesis of Disfavored Diastereomers (Journal of the American Chemical Society (2019) 141 (12029-12043) DOI: 10.1021/jacs.9b04902)
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Page 12035 and Supporting Information pp S91-S94. It has come to our attention that the wrong initial concentration of 1a was erroneously used in two experiments of the "same excess" protocol.1 The experiments were thus repeated (0.055 rather than 0.06 mol/L of 1a was erroneously used before), and an excellent overlay of the "time-adjusted same excess" reaction profiles and the standard reaction profile, as previously presented, was found. This indicates that no significant catalyst deactivation takes place and that the active catalyst concentration remains constant during the catalytic reaction. The conclusions are thus not affected by the unintentional error. The corrected Figure 1 is shown below, and a corrected including Figures S1-S28 and Tables S1-S8 (corrected).(Figure Persented).Supporting Information file is available, in which pp S91?S94 have been replaced, in which the correct kinetic experiments are described, including raw data. We apologize for any inconvenience.
- Willig, Felix,Lang, Johannes,Hans, Andreas C.,Ringenberg, Mark R.,Pfeffer, Daniel,Frey, Wolfgang,Peters, René
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supporting information
p. 17022 - 17022
(2019/11/14)
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- Broad activity of diphenyleneiodonium analogues against Mycobacterium tuberculosis, malaria parasites and bacterial pathogens
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In this study, a structure-activity relationship (SAR) compound series based on the NDH-2 inhibitor diphenyleneiodonium (DPI) was synthesised. Compounds were evaluated primarily for in vitro efficacy against Gram-positive and Gram-negative bacteria, commonly responsible for nosocomial and community acquired infections. In addition, we also assessed the activity of these compounds against Mycobacterium tuberculosis (Tuberculosis) and Plasmodium spp. (Malaria). This led to the discovery of highly potent compounds active against bacterial pathogens and malaria parasites in the low nanomolar range, several of which were significantly less toxic to mammalian cells.
- Nguyen, Nghi,Wilson, Danny W.,Nagalingam, Gayathri,Triccas, James A.,Schneider, Elena K.,Li, Jian,Velkov, Tony,Baell, Jonathan
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p. 507 - 518
(2017/12/26)
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- TRANSITION METAL COMPOUND, CATALYST FOR OLEFIN MULTIMERIZATION AND METHOD FOR PRODUCING OLEFIN MULTIMER
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PROBLEM TO BE SOLVED: To provide a novel transition metal compound, a catalyst for olefin multimerization containing the compound and having excellent activity and selectivity, and a method for producing an olefin multimer that is performed in the presence of the catalyst for olefin multimerization. SOLUTION: The present invention provides a transition metal compound of general formula (1), a catalyst for olefin polymerization containing the same, and a method for producing an olefin polymer with the catalyst (R1-R6 are a hydrogen atom or the like, M is a transition metal atom in the periodic table group 6, n is a valence of M, X is a halogen atom or the like, Y is an oxygen atom or the like, Z is a hydrocarbon group or the like, Q is an oxygen atom having a substituent, or the like). SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
- -
-
Paragraph 0202; 0204
(2018/11/22)
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- TRANSITION METAL COMPOUND, CATALYST FOR OLEFIN MULTIMERIZATION AND METHOD FOR PRODUCING OLEFIN MULTIMER
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PROBLEM TO BE SOLVED: To provide a novel transition metal compound, a catalyst for olefin multimerization containing the compound and having excellent activity and selectivity, and a method for producing an olefin multimer that is performed in the presence of the catalyst for olefin multimerization. SOLUTION: The present invention provides a transition metal compound of general formula (1), a catalyst for olefin polymerization containing the same, and a method for producing an olefin polymer with the catalyst (R1-R6 are a hydrogen atom or the like, M is a transition metal atom in the periodic table group 6, n is a valence of M, X is a halogen atom or the like, Y is an oxygen atom or the like, Z is a hydrocarbon group or the like). SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
- -
-
Paragraph 0206; 0208
(2018/11/22)
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- Visible-light-promoted intramolecular C-H amination in aqueous solution: Synthesis of carbazoles
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An effective and operationally simple protocol is reported for the synthesis of versatile carbazoles. With water as a co-solvent, visible-light rather than various metals is used to facilitate the conversion of readily available 2-azidobiphenyls under mild conditions. Various functionalized bioactive natural alkaloids, such as glycoborine, clausine C, clausine L, clausine H and clauszoline K, were synthesized efficiently with nitrogen as a sole byproduct. The reaction could be performed in water, acidic or alkaline buffer solutions, showing its potential for applications in biochemistry.
- Yang, Lizheng,Zhang, Yipin,Zou, Xiaodong,Lu, Hongjian,Li, Guigen
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supporting information
p. 1362 - 1366
(2018/03/26)
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- Visible-light-mediated radical insertion/cyclization cascade reaction: Synthesis of phenanthridines and isoquinolines from isocyanides
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A visible-light promoted single electron oxidation of ether enabled by photoredox catalysis has been accomplished. This procedure initiates a novel radical insertion/cyclization cascade reaction to generate phenanthridines and isoquinolines from easily available isocyanides under mild reaction conditions.
- Feng, Shangbiao,Li, Tao,Du, Chenglong,Chen, Peng,Song, Dengpeng,Li, Jinlai,Xie, Xingang,She, Xuegong
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supporting information
p. 4585 - 4588
(2017/04/28)
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- Understanding difficulties of irregular number-membered ring transition states for intramolecular proton transfer in excited state
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This study presents a variety of organic dyes with similar molecular structures that could undergo intramolecular proton transfer in excited states via five-, six- and seven-number-membered ring transition states, respectively. In addition, the dyes without proton transfer segments are also synthesized to use as references. X-ray single crystal diffraction, NMR spectra as well as UV/visible spectra suggests the presence of internal hydrogen bond with different strength in the target dyes. The steady and transient fluorescence measurements demonstrate occurrence of excited state intramolecular proton transfer via a six number-membered ring transition state. In contrast, it cannot be processed through five- and seven-number-membered ring transition states of the studied dyes. The molecular geometry optimization of the studied dyes reveals fundamental factors for the difficulties of intramolecular proton transfer in excited states via five- and seven-number-membered ring transition states.
- Qin, Xiaozhuan,Ding, Ge,Wang, Zhenqiang,Gong, Yulong,Gao, Fang,Zhang, Shengtao,Luo, Ziping,Li, Hongru
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supporting information
p. 403 - 410
(2017/01/03)
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- TRANSITION METAL COMPOUND, CATALYST FOR OLEFIN POLYMERIZATION CONTAINING THE COMPOUND AND MANUFACTURING METHOD OF OLEFIN POLYMER CONDUCTED IN PRESENCE OF THE CATALYST
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PROBLEM TO BE SOLVED: To provide a novel transition metal catalyst for olefin polymerization and a manufacturing method of an olefin polymer, especially 1-hexene by trimerizing ethylene in presence of the catalyst. SOLUTION: There is provided a compound represented by the compound 3 as a catalyst. There is provided a transition metal catalyst for olefin polymerization further containing a compound such as triphenyl carbenium tetrakis(pentafluorophenyl)borate forming an ion pair by reacting an organic aluminum oxy compound and a catalyst metal compound and providing 1-hexene from ethylene at good yield. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0169
(2017/07/23)
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- Indium powder as the reducing agent in the synthesis of 2-amino-1,1′-biphenyls
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An improved and simplified In-based protocol for the reduction of 2-nitro-1,1′-biphenyls to the corresponding 2-amino-1,1′-biphenyls is disclosed. The method utilizes only a stoichiometric quantity of indium powder as the reducing reagent along with a stoichiometric quantity of ammonium chloride. The work-up is very simple, it requires only a simple filtration of the post-reaction mixture whereupon the reaction medium is removed under reduced pressure. The method was also proven to operate with a variety of functional groups to provide high to excellent yields of the target 2-amino-1,1′-biphenyls. A proposal for a reaction mechanism is also provided.
- Elumalai, Vijayaragavan,Bj?rsvik, Hans-René
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supporting information
p. 1224 - 1226
(2016/03/01)
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- Synthesis of the Carbazole Scaffold Directly from 2-Aminobiphenyl by Means of Tandem C–H Activation and C–N Bond Formation
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An efficient method for the synthesis of the carbazole scaffold was designed and investigated. The method was developed to produce substituted carbazoles by an intramolecular combination of a free amine group and an arene. The steps of the method involved tandem Pd-catalyzed C–H activation and intramolecular C–N bond formation. The method showed good functional group tolerance, and substituent(s) could be on either of the two rings or on both of the two rings of the 2-aminobiphenyl substrate. After ring closure, the reduced Pd catalyst was oxidized to PdIIby hydrogen peroxide. The novel method was also demonstrated to operate excellently with the corresponding 2-N-acetylaminobiphenyls.
- Bj?rsvik, Hans-René,Elumalai, Vijayaragavan
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supporting information
p. 5474 - 5479
(2016/11/25)
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- Radical Fluoroalkylation of Isocyanides with Fluorinated Sulfones by Visible-Light Photoredox Catalysis
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The radical fluoroalkylation of isocyanides with fluorinated sulfones is enabled by visible-light photoredox catalysis. A wide range of readily available mono-, di-, and trifluoromethyl heteroaryl sulfones can thus be used as efficient radical fluoroalkylation reagents under mild conditions. This method not only describes a new synthetic application of fluorinated sulfones, but also provides a new route to fluoroalkyl radicals.
- Rong, Jian,Deng, Ling,Tan, Ping,Ni, Chuanfa,Gu, Yucheng,Hu, Jinbo
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supporting information
p. 2743 - 2747
(2016/02/26)
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- Heterogeneous Catalysis by Covalent Organic Frameworks (COF): Pd(OAc)2@COF-300 in Cross-Coupling Reactions
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COF-300, an imine-linked, crystalline, and microporous covalent organic framework, modified by coordination of Pd(OAc)2 to its walls, afforded a hybrid material, Pd(OAc)2@COF-300, which was used as an efficient heterogeneous catalyst for cross-coupling reactions. This material showed excellent catalytic activity for the phosphine-free Suzuki-Miyaura, Heck, and Sonogashira cross-coupling reactions with low palladium loadings (0.1mol % Pd). X-ray photoelectron spectroscopy analysis of the catalyst after the reaction showed that PdII is converted to Pd0, which is trapped within the COFs nanopores. This was confirmed by high-resolution transmission electron microscopy. Moreover, promising results were obtained using Pd(OAc)2@COF-300 under continuous-flow conditions for a Suzuki-Miyaura cross-coupling reaction.
- Gon?alves, Raoni S. B.,Deoliveira, Alline B. V.,Sindra, Haryadylla C.,Archanjo, Bráulio S.,Mendoza, Martín E.,Carneiro, Leonardo S. A.,Buarque, Camilla D.,Esteves, Pierre M.
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p. 743 - 750
(2016/03/05)
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- Synthesis of Fluorenes Starting from 2-Iodobiphenyls and CH2Br2 through Palladium-Catalyzed Dual C-C Bond Formation
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A facile and efficient approach is developed for the synthesis of fluorene and its derivatives starting from 2-iodobiphenyls and CH2Br2. A range of fluorene derivatives can be synthesized under relatively mild conditions. The reaction proceeds via a tandem palladium-catalyzed dual C-C bond formation sequence through the key dibenzopalladacyclopentadiene intermediates, which are obtained from 2-iodobiphenyls through palladium-catalyzed C-H activation.
- Shi, Guangfa,Chen, Dushen,Jiang, Hang,Zhang, Yu,Zhang, Yanghui
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supporting information
p. 2958 - 2961
(2016/07/06)
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- Synthesis of Triphenylenes Starting from 2-Iodobiphenyls and Iodobenzenes via Palladium-Catalyzed Dual C-H Activation and Double C-C Bond Formation
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A novel and facile approach for the synthesis of triphenylenes has been developed via palladium-catalyzed coupling of 2-iodobiphenyls and iodobenzenes. The reaction involves dual palladium-catalyzed C-H activations and double palladium-catalyzed C-C bond formations. A range of unsymmetrically functionalized triphenylenes can be synthesized with the reaction. The approach features readily available starting materials, high atom- and step-economy, and access to various unsymmetrically functionalized triphenylenes.
- Zhang, Yanghui,Pan, Shulei,Jiang, Hang,Zhang, Yu,Chen, Dushen
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supporting information
p. 5192 - 5195
(2016/11/02)
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- MeOTf- and TBD-Mediated Carbonylation of ortho-Arylanilines with CO2 Leading to Phenanthridinones
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Carbonylation of o-arylanilines utilizing CO2 as a carbonyl source for the synthesis of important phenanthridinones with a free (NH)-lactam motif has been described under metal-free condition. A range of o-arylanilines were transformed to the corresponding phenanthridinones in high yields.
- Wang, Sheng,Shao, Peng,Du, Gaixia,Xi, Chanjuan
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p. 6672 - 6676
(2016/08/16)
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- Palladium-Catalyzed Intramolecular C–H Amination in Water
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Palladium(II) catalysis was found to be effective for intramolecular C–H amination in water. With 2-azidobiphenyls as substrates, the reaction efficiently provided various carbazoles with N2as the sole byproduct. The reaction showed high functional-group tolerance and could be used in the synthesis of several natural carbazole alkaloids. The catalytic process was promoted by water, and the reaction was inefficient in the organic solvents that were investigated.
- Yang, Lizheng,Li, Hao,Zhang, Haifei,Lu, Hongjian
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supporting information
p. 5611 - 5615
(2016/12/14)
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- Direct synthesis of N -H carbazoles via iridium(III)-catalyzed intramolecular C-H amination
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The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of a copper cocatalyst under air as a terminal oxidant through intramolecular direct C-H amination to produce N-H carbazoles. A similar iridium/copper system can also catalyze the unprecedented dimerization reaction of 2-aminobiphenyl involving 2-fold C-H/N-H couplings.
- Suzuki, Chiharu,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 1597 - 1600
(2015/03/30)
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- Lewis acid promoted titanium alkylidene formation: Off-cycle intermediates relevant to olefin trimerization catalysis
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Two new precatalysts for ethylene and α-olefin trimerization, (FI)Ti(CH2SiMe3)2Me and (FI)Ti(CH2CMe3)2Me (FI = phenoxy-imine), have been synthesized and structurally characterized by X-ray diffraction. (FI)Ti(CH2SiMe3)2Me can be activated with 1 equiv of B(C6F5)3 at room temperature to give the solvent-separated ion pair [(FI)Ti(CH2SiMe3)2][MeB(C6F5)3], which catalytically trimerizes ethylene or 1-pentene to produce 1-hexene or C15 olefins, respectively. The neopentyl analogue (FI)Ti(CH2CMe3)2Me is unstable toward activation with B(C6F5)3 at room temperature, giving no discernible diamagnetic titanium complexes, but at -30 °C the following can be observed by NMR spectroscopy: (i) formation of the bis-neopentyl cation [(FI)Ti(CH2CMe3)2]+, (ii) α-elimination of neopentane to give the neopentylidene complex [(FI)Ti(=CHCMe3)]+, and (iii) subsequent conversion to the imido-olefin complex [(MeOAr2N=)Ti(OArHC=CHCMe3)]+ via an intramolecular metathesis reaction with the imine fragment of the (FI) ligand. If the reaction is carried out at low temperature in the presence of ethylene, catalytic production of 1-hexene is observed, in addition to the titanacyclobutane complex [(FI)Ti(CH(CMe3)CH2CH2)]+, resulting from addition of ethylene to the neopentylidene [(FI)Ti(=CHCMe3)]+. None of the complexes observed spectroscopically subsequent to [(FI)Ti(CH2CMe3)2]+ is an intermediate or precursor for ethylene trimerization, but notwithstanding these off-cycle pathways, [(FI)Ti(CH2CMe3)2]+ is a precatalyst that undergoes rapid initiation to generate a catalyst for trimerizing ethylene or 1-pentene.
- Sattler, Aaron,Vandervelde, David G.,Labinger, Jay A.,Bercaw, John E.
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p. 10790 - 10800
(2014/08/18)
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- Synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation-cyclization of α-oxocarboxylates and isocyanides
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A silver catalysed synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation-cyclization of α-oxocarboxylates and isocyanides was developed. This reaction provided a novel method to realize C1 insertion via a radical process and various functional groups were well-tolerated. The Royal Society of Chemistry.
- Liu, Jie,Fan, Chao,Yin, Hongyu,Qin, Chu,Zhang, Guoting,Zhang, Xu,Yi, Hong,Lei, Aiwen
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supporting information
p. 2145 - 2147
(2014/02/14)
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- Highly selective olefin trimerization catalysis by a borane-activated titanium trimethyl complex
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Reaction of a trimethyl titanium complex, (FI)TiMe3 (FI = phenoxy-imine), with 1 equiv of B(C6F5)3 gives [(FI)TiMe2][MeB(C6F5)3], an effective precatalyst for the selective trimerization of ethylene. Mechanistic studies indicate that catalyst initiation involves generation of an active TiII species by olefin insertion into a Ti-Me bond, followed by β-H elimination and reductive elimination of methane, and that initiation is slow relative to trimerization. (FI)TiMe3/B(C6F 5)3 also leads to a competent catalyst for the oligomerization of α-olefins, displaying high selectivity for trimers (>95%), approximately 85% of which are one regioisomer. This catalyst system thus shows promise for selectively converting light α-olefins into transportation fuels and lubricants.
- Sattler, Aaron,Labinger, Jay A.,Bercaw, John E.
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supporting information
p. 6899 - 6902
(2014/01/06)
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- Quinolinyl- and phenantridinyl-acetamides as bradykinin B1 receptor antagonists
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A new series of quinolinyl- and phenantridinyl-acetamides were synthesizer and evaluated against bradykinin B1 receptor. In vitro metabolic stability data were reported for the key compounds.The analgesic effect of compound 20 from the phenantridine series was proved in-vivo.
- éles, János,Beke, Gyula,Vágó, István,Bozó, éva,Huszár, József,Tarcsay, ákos,Kolok, Sándor,Schmidt, éva,Vastag, Mónika,Hornok, Katalin,Farkas, Sándor,Domány, Gy?rgy,Keser, Gy?rgy M.
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scheme or table
p. 3095 - 3099
(2012/06/17)
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- Pd-catalyzed sequential C-C and C-N bond formations for the synthesis of N-heterocycles: Exploiting protecting group-directed C-H activation under modified reaction conditions
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Easy & efficient: A Pd-catalyzed domino olefination/conjugate addition reaction of N-Ts-2-arylanilines with activated olefins has been achieved at ambient temperature under the newly defined reaction conditions. This process highlighted the directing effect of the N-protecting group in C-H activation, displayed broad substrate scope with wide functional group compatibility; thus rendering a straightforward entry to a wide variety of N-heterocycles such as dihydrophenanthridines.
- Kim, Byung Seok,Lee, Sun Young,Youn, So Won
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supporting information; experimental part
p. 1952 - 1957
(2011/11/04)
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- Efficient synthesis of phenanthridines using Hendrickson reagent initiated cascade reaction under mild conditions
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A number of variously substituted phenanthridines have been synthesized using the newly developed methodology under mild conditions. The Hendrickson reagent initiated cascade annulation, which is composed of a mild conversion of stable amide precursor to highly reactive imido-carbonium intermediate and a subsequent intramolecular Friedel-Crafts reaction, successfully served as the key method. Georg Thieme Verlag Stuttgart New York.
- Xi, Jie,Dong, Qing-Li,Liu, Guan-Sai,Wang, Shaozhong,Chen, Lin,Yao, Zhu-Jun
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supporting information; experimental part
p. 1674 - 1678
(2010/08/20)
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- TRANSITION METAL COMPLEX COMPOUND, OLEFIN POLYMERIZATION CATALYST CONTAINING THE COMPOUND, AND METHOD FOR PRODUCING OLEFIN POLYMER PERFORMED IN THE PRESENCE OF THE CATALYST
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The invention provides transition metal complex compounds, high-activity olefin oligomerization catalysts containing the compounds, and olefin oligomerization processes using the catalysts. A transition metal complex compound [A] according to the invention is represented by Formula (I) or Formula (I') below. An olefin oligomerization catalyst includes the transition metal complex compound [A]. In an olefin oligomerization process of the invention, an olefin is oligomerized in the presence of the catalyst.
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Page/Page column 34-35
(2010/04/30)
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- Trifluoroacetic acid-mediated facile construction of 6-substituted phenanthridines
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The trifluoroacetic acid-mediated reaction of 2-arylanilines with arylaldehydes has been developed to give a variety of 6-substituted phenanthridines. This is a very simple and convenient one-pot process for library construction.
- Youn, So Won,Bihn, Joon Hyung
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scheme or table
p. 4598 - 4601
(2009/10/11)
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- Radical dearomatization of arenes and heteroarenes
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The stannane-mediated benzeneselenol-catalyzed addition of aryl iodides to a range of arenes and aromatic hetereocycles has been studied. With furan, thiophene, and several carbocyclic arenes, the addition takes place with quenching of the adduct radical by the catalytic selenol leading to moderate yields of aryl-dihydroarenes. With nitrogen heterocycles, on the other hand, it was not possible to suppress aromatization of the adduct radical and fully aromatized products were isolated. Aryl iodides bearing hydrogen bond donating groups in the ortho-position add to nitrogen heterocycles with high selectivity ortho- to the nitrogen, affording a simple one-step synthesis of potential chelating ligands. While 2-iodophenol is an excellent aryl radical source in these reactions, the homologous 1-iodo-2-naphthol fails owing to its reaction with diphenyl diselenide, which gives 1-phenylseleno-2-naphthol in high yield.
- Crich, David,Patel, Mitesh
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p. 7824 - 7837
(2007/10/03)
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- Imidazoline derivatives as alpha-1A adrenoceptor ligands
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Compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof are disclosed. Such compounds are useful in the treatment of Alpha-1A mediated diseases or conditions such as urinary incontinence.
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Page/Page column 28
(2010/02/11)
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- Aryl carbamate derivatives, preperation and use thereof
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The present invention relates to novel compounds, the preparation and use, particularly therapeutic, thereof. More specifically, it relates to compounds derived from aryl carbamates, the preparation and use thereof, particularly in the field of human and animal health. The compounds according to the invention are preferably 5-HT4 serotoninergic receptor ligands and can therefore be used in the therapeutic or prophylactic treatment of any disorder involving a 5-HT4 receptor. The invention also relates to pharmaceutical compositions comprising such compounds, the preparation and use thereof and treatment methods using said compounds.
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Page/Page column 8
(2010/02/06)
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- N- and C-attacks on aromatics of phenylnitrenium ion generated from N-phenylhydroxylamine in the presence of trifluoroacetic acid containing polyphosphoric acid or trifluoroacetic anhydride
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A phenylnitrenium ion formed from N-phenylhydroxylamine in the presence of trifluoroacetic acid (TFA) containing polyphosphoric acid (PPA) interacts with the counterion -O2CCF3 and the unshared electron-pair of H2O, showing Hammett's ρ values -5.2 and -4.0 for N- and C-attacks on aromatics PhX (X = H, Me, Et, Ph and Cl), respectively. The ratio N-/C-attack for this nitrenium ion is lower than for the nitrenium ion interacting with only the counterion; the latter nitrenium ion is generated by the use of trifluoroacetic anhydride (TFAA) instead of PPA or by reaction of phenyl azide with aromatics in TFA. The ratio for the former nitrenium ion is affected by the aromatic substituent X:X = Me > X = Et > X = Ph > X = H > X = OMe at 20 and 50°C. The order for X = Cl is between those of X = H and X = Ph at 20°C, but highest at 50°C. The ratio is increased by higher reaction temperature and by decreased concentration of TFA. The results are demonstrated from the mechanistic viewpoint for the nitrenium ions.
- Takeuchi, Hiroshi,Taniguchi, Tomohito,Ueda, Takahiro
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p. 295 - 300
(2007/10/03)
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- Cyclisation reactions of 2-substituted biphenyl-2'-yldiazonium salts leading to O-alkyldibenzofuranium and S-alkyldibenzothiophenium salts: Modified Meerwein reagents
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The preparation of 2-amino-2'-methoxybiphenyl and 2-amino-2'-thiomethoxybiphenyl and analogues and their transformation into diazonium salts and hence into dibenzofuranium and dibenzothiophenium salts is described together with their use as alkylating agents.
- Downie,Heaney,Kemp,King,Wosley
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p. 4005 - 4016
(2007/10/02)
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