- IrIII-based Octahedral Metalloligands Derived Primitive Cubic Frameworks for Enhanced CO2/N2 Separation
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We developed a metalloligand strategy to construct porous frameworks, viz. the combined use of IrIII-based octahedral metalloligands and the linear unit [Ni(cyclam)] easily afforded two isostructural complexes 1 and 2 with primitive cubic frameworks. Both complexes show good CO2/N2 separation property.
- Huang, Sheng-Li,Liu, Naifang,Ling, Yun,Luo, He-Kuan
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Read Online
- Synthesis and evaluation of tiaprofenic acid-derived UCHL5 deubiquitinase inhibitors
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The ubiquitin–proteasome system (UPS) plays an important role in maintaining protein homeostasis by degrading intracellular proteins. In the proteasome, poly-ubiquitinated proteins are deubiquitinated by three deubiquitinases (DUBs) associated with 19S re
- Gurusingha Arachchige, Harshani S.,Herath Mudiyanselage, Poornima D.H.,VanHecke, Garrett C.,Patel, Kush,Cheaito, Hassan A.,Dou, Q. Ping,Ahn, Young-Hoon
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supporting information
(2020/12/25)
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- Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
- Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
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supporting information
p. 15396 - 15405
(2021/10/12)
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- Hydride Transfer Enables the Nickel-Catalyzed ipso-Borylation and Silylation of Aldehydes
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Nickel-catalyzed ipso-borylations and silylations of aldehydes are described for the first time. The new functional-group interconversion protocol is characterized by its scalability, functional-group tolerance and wide substrate scope, including examples of late-stage functionalization of complex molecules. The key for the successful reaction outcome is the use of a ketone as a hydride acceptor that intercepts the nickel hydride to undergo a reductive pathway, thus allowing formation of the desired C?B and C?Si bonds.
- Srimontree, Watchara,Guo, Lin,Rueping, Magnus
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supporting information
p. 423 - 427
(2019/12/27)
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- Visible Light-Induced Borylation of C-O, C-N, and C-X Bonds
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Boronic acids are centrally important functional motifs and synthetic precursors. Visible light-induced borylation may provide access to structurally diverse boronates, but a broadly efficient photocatalytic borylation method that can effect borylation of a wide range of substrates, including strong C-O bonds, remains elusive. Herein, we report a general, metal-free visible light-induced photocatalytic borylation platform that enables borylation of electron-rich derivatives of phenols and anilines, chloroarenes, as well as other haloarenes. The reaction exhibits excellent functional group tolerance, as demonstrated by the borylation of a range of structurally complex substrates. Remarkably, the reaction is catalyzed by phenothiazine, a simple organic photocatalyst with MW 200 that mediates the previously unachievable visible light-induced single electron reduction of phenol derivatives with reduction potentials as negative as approximately - 3 V versus SCE by a proton-coupled electron transfer mechanism. Mechanistic studies point to the crucial role of the photocatalyst-base interaction.
- Arman, Hadi D.,Dang, Hang. T.,Haug, Graham C.,He, Ru,Jin, Shengfei,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Schanze, Kirk S.
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supporting information
(2020/02/04)
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- Reductive Electrophotocatalysis: Merging Electricity and Light to Achieve Extreme Reduction Potentials
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We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of -3.2 V vs SCE, which can be used to activate substrates with very high reduction potentials (Ered ≈ -1.9 to -2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.
- Kim, Hyunwoo,Kim, Hyungjun,Lambert, Tristan H.,Lin, Song
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supporting information
p. 2087 - 2092
(2020/02/04)
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- Controllable factors of supported IR complex catalysis for aromatic C?H borylation
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We have developed a catalyst in which an Ir complex and organic functionalities are coimmobilized on the silica surface. The catalytic activity for aromatic C?H borylation was significantly affected by (i) the linker length of the Ir?bipyridine complex, (ii) the coimmobilized organic functionality, and (iii) the substituents on the aromatic substrate compounds. The fine-tuned supported catalyst showed higher activity than the homogeneous Ir?bipyridine complex when using a specific substrate such as benzonitrile. We elucidated this property by conducting solid-state NMR, FT-IR, XAFS, and in situ FT-IR analysis.
- Chun, Wang-Jae,Maeda, Kyogo,Manaka, Yuichi,Motokura, Ken,Nakajima, Kiyotaka,Satter, Shazia Sharmin,Uemura, Yohei
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p. 14552 - 14559
(2020/12/21)
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- Cleavage of C(aryl)?CH3 Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
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Organic chemists now can construct carbon–carbon σ-bonds selectively and sequentially, whereas methods for the selective cleavage of carbon–carbon σ-bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site-selective cleavage and borylation of C(aryl)?CH3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes are selectively cleaved and replaced by boryl groups. Mechanistic analysis suggests that it proceeds by a sequential intermolecular oxidation and coupling of a transient aryl radical, generated by radical decarboxylation, involving a pyridine-stabilized persistent boryl radical.
- Dai, Peng-Fei,Ning, Xiao-Shan,Wang, Hua,Cui, Xian-Chao,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5392 - 5395
(2019/03/29)
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- Hydrogenation of (Hetero)aryl Boronate Esters with a Cyclic (Alkyl)(amino)carbene–Rhodium Complex: Direct Access to cis-Substituted Borylated Cycloalkanes and Saturated Heterocycles
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We herein report the hydrogenation of substituted aryl- and heteroaryl boronate esters for the selective synthesis of cis-substituted borylated cycloalkanes and saturated heterocycles. A cyclic (alkyl)(amino)carbene-ligated rhodium complex with two dimethyl groups at the ortho-alkyl scaffold of the carbene showed high reactivity in promoting the hydrogenation, thereby enabling the hydrogenation of (hetero)arenes with retention of the synthetically valuable boronate group. This process constitutes a clean, atom-economic, as well as chemo- and stereoselective route for the generation of cis-configured, diversely substituted borylated cycloalkanes and saturated heterocycles that are usually elusive and difficult to prepare.
- Ling, Liang,He, Yuan,Zhang, Xue,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 6554 - 6558
(2019/04/17)
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- Hydrogen Bond Directed ortho-Selective C?H Borylation of Secondary Aromatic Amides
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Reported is an iridium catalyst for ortho-selective C?H borylation of challenging secondary aromatic amide substrates, and the regioselectivity is controlled by hydrogen-bond interactions. The BAIPy-Ir catalyst forms three hydrogen bonds with the substrate during the crucial activation step, and allows ortho-C?H borylation with high selectivity. The catalyst displays unprecedented ortho selectivities for a wide variety of substrates that differ in electronic and steric properties, and the catalyst tolerates various functional groups. The regioselective C?H borylation catalyst is readily accessible and converts substrates on gram scale with high selectivity and conversion.
- Bai, Shao-Tao,Bheeter, Charles B.,Reek, Joost N. H.
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supporting information
p. 13039 - 13043
(2019/07/31)
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- Meta-Selective C-H Borylation of Benzamides and Pyridines by an Iridium-Lewis Acid Bifunctional Catalyst
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We report herein the iridium-catalyzed meta-selective C-H borylation of benzamides by using a newly designed 2,2′-bipyridine (bpy) ligand bearing an alkylaluminum biphenoxide moiety. We also demonstrate the iridium-catalyzed C3-selective C-H borylation of pyridine with a 1,10-phenanthroline (Phen) ligand bearing an alkylborane moiety. It is proposed that the Lewis acid-base interaction between the Lewis acid moiety and the aminocarbonyl group or the sp2-hybridized nitrogen atom accelerates the reaction and controls the site-selectivity.
- Yang, Lichen,Uemura, Nao,Nakao, Yoshiaki
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supporting information
p. 7972 - 7979
(2019/05/22)
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- Palladium-Catalyzed Decarbonylative Borylation of Carboxylic Acids: Tuning Reaction Selectivity by Computation
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Decarbonylative borylation of carboxylic acids is reported. Carbon electrophiles are generated directly after reagent-enabled decarbonylation of the in situ accessible sterically-hindered acyl derivative of a carboxylic acid under catalyst controlled conditions. The scope and the potential impact of this method are demonstrated in the selective borylation of a variety of aromatics (>50 examples). This strategy was used in the late-stage derivatization of pharmaceuticals and natural products. Computations reveal the mechanistic details of the unprecedented C?O bond activation of carboxylic acids. By circumventing the challenging decarboxylation, this strategy provides a general synthetic platform to access arylpalladium species for a wide array of bond formations from abundant carboxylic acids. The study shows a powerful combination of experiment and computation to predict decarbonylation selectivity.
- Liu, Chengwei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 16721 - 16726
(2018/11/30)
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- Pd II -Porphyrin Complexes - The First Use as Safer and Efficient Catalysts for Miyaura Borylation
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We have developed a simple and convenient procedure for the preparation of pinacol arylboronates from aryl/heteroaryl bromides and bis(pinacolato)diborane using a Pd II -porphyrin complex as a catalyst. Seven different Pd II -porphyrin complexes (Pd II -T m HPP, Pd II -T m CPP, Pd II -TPP, Pd II -TST p SPP, Pd II -T p CPP, Pd II -T p TP, and Pd II -T p AP) have been synthesized and investigated for their catalytic influence in the Miyaura borylation.
- Rao, Kanusu Umamaheswara,Venkateswarlu, Katta
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supporting information
p. 1055 - 1060
(2018/03/23)
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- Room-temperature borylation and one-pot two-step borylation/Suzuki-Miyaura cross-coupling reaction of aryl chlorides
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A highly efficient room-temperature borylation strategy of aryl chlorides is described. Utilizing Buchwald's second-generation preformed catalyst, boronate esters were obtained for a wide range of substrates in high yield. The method was also applied to Suzuki-Miyaura cross-coupling reaction in a one-pot two-step sequential manner, providing a facile and convenient access to the direct synthesis of biaryl compounds from aryl chlorides.
- Ji, Hong,Wu, Li-Yang,Cai, Jiang-Hong,Li, Guo-Rong,Gan, Na-Na,Wang, Zhao-Hua
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p. 13643 - 13648
(2018/04/24)
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- Room Temperature Ni0/PCy3-Catalyzed Coupling Reactions of Aryl Arenesulfonates with Bis(pinacolato)diboron
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Room temperature Ni0/PCy3-catalyzed cross-coupling reactions of aryl arenesulfonates with bis(pinacolato)diboron are described. The Ni0/PCy3 catalysts, generated from Ni(COD)2 and PCy3, or air-stable 4-MeOC6H4NiII(PCy3)2OTs, were efficient catalyst systems for the Miyaura borylation reactions of a variety of aryl arenesulfonates with bis(pinacolato)diboron. The mild reaction condition, the easy availability of the catalysts and good yields make these reactions potentially useful in organic synthesis (Cy = cyclohexyl, COD = cyclooctadiene, OTs = tosyl).
- Dong, Jie,Guo, Hui,Hu, Qiao-Sheng
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supporting information
p. 7087 - 7090
(2017/12/28)
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- Visible-Light Photoredox Borylation of Aryl Halides and Subsequent Aerobic Oxidative Hydroxylation
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Efficient and practical visible-light photoredox borylation of aryl halides and subsequent aerobic oxidative hydroxylation were developed. The protocols use readily available aryl halides and bis(pinacolato)diboron as the starting materials, fac-Ir(ppy)3 as the photocatalyst, and corresponding arylboronic esters and phenols were obtained in good yields. The methods show some advantages including simple equipment, mild conditions, easy operation, and wide substrate scope. Therefore, they should provide a valuable strategy for chemical transformations.
- Jiang, Min,Yang, Haijun,Fu, Hua
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supporting information
p. 5248 - 5251
(2016/11/02)
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- High-Turnover Aromatic C-H Borylation Catalyzed by POCOP-Type Pincer Complexes of Iridium
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The catalytic C-H borylation of arenes with HBpin (pin = pinacolate) using POCOP-type pincer complexes of Ir has been demonstrated, with turnover numbers exceeding 10 000 in some cases. The selectivity of C-H activation was based on steric preferences and largely mirrored that found in other Ir borylation catalysts. Catalysis in the (POCOP)Ir system depends on the presence of stoichiometric quantities of sacrificial olefin, which is hydrogenated to consume the H2 equivalents generated in the borylation of C-H bonds with HBpin. Smaller olefins such as ethylene or 1-hexene were more advantageous to catalysis than sterically encumbered tert-butylethylene (TBE). Olefin hydroboration is a competing side reaction. The synthesis and isolation of multiple complexes potentially relevant to catalysis permitted examination of several key elementary reactions. These experiments indicate that the C-H activation step in catalysis ostensibly involves oxidative addition of an aromatic C-H bond to the three-coordinate (POCOP)Ir species. The olefin is mechanistically critical to gain access to this 14-electron, monovalent Ir intermediate. C-H activation at Ir(I) here is in contrast to the olefin-free catalysis with state-of-the-art Ir complexes supported by neutral bidentate ligands, where the C-H activating step is understood to involve trivalent Ir-boryl intermediates.
- Press, Loren P.,Kosanovich, Alex J.,McCulloch, Billy J.,Ozerov, Oleg V.
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supporting information
p. 9487 - 9497
(2016/08/12)
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- The drastic effect of cobalt and chromium catalysts in the borylation of arylzinc reagents
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A new synthetic approach to arylboronic esters from arylzinc reagents with boryl electrophiles MeOB(OR)2 has been developed. Furthermore, this protocol could be applied to the cyclization/borylation of alkynylaryl iodides to afford cyclized vinylboronic esters.
- Komeyama, Kimihiro,Kiguchi, Shinnosuke,Takaki, Ken
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supporting information
p. 7009 - 7012
(2016/06/09)
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- Metal-Organic Frameworks Stabilize Mono(phosphine)-Metal Complexes for Broad-Scope Catalytic Reactions
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Mono(phosphine)-M (M-PR3; M = Rh and Ir) complexes selectively prepared by postsynthetic metalation of a porous triarylphosphine-based metal-organic framework (MOF) exhibited excellent activity in the hydrosilylation of ketones and alkenes, the hydrogenation of alkenes, and the C-H borylation of arenes. The recyclable and reusable MOF catalysts significantly outperformed their homogeneous counterparts, presumably via stabilizing M-PR3 intermediates by preventing deleterious disproportionation reactions/ligand exchanges in the catalytic cycles.
- Sawano, Takahiro,Lin, Zekai,Boures, Dean,An, Bing,Wang, Cheng,Lin, Wenbin
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supporting information
p. 9783 - 9786
(2016/08/19)
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- Iridium-bipyridine periodic mesoporous organosilica catalyzed direct C-H borylation using a pinacolborane
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Heterogeneous catalysis for direct C-H borylation of arenes and heteroarenes in the combination of iridium (Ir) complex fixed on periodic mesoporous organosilica containing bipyridine ligands within the framework (Ir-BPy-PMO) and pinacolborane (HBpin) is reported. Ir-BPy-PMO showed higher catalytic activity toward the borylation of benzene with inexpensive HBpin compared to expensive bis(pinacolato)diboron (B2pin2). The precatalyst could be handled without the use of a glove box. The catalyst was easily recovered from reaction mixtures by simple filtration under air. The recovered catalyst still showed good catalytic activity for at least three more times for the borylation of benzene. A variety of arenes and heteroarenes were successfully borylated with high boron efficiency by Ir-BPy-PMO using HBpin, whereas almost no activity was observed for borylation of some heteroarenes with B2pin2. The system using Ir-BPy-PMO and HBpin was also utilized in syntheses of multi-boronated thiophene-based building blocks containing ladder-, acenefused-, and fused-thiophene skeletons. The combination of a stable and reusable solid catalyst and inexpensive HBpin is expected to be superior to conventional approaches for the development of industrial applications.
- Maegawa, Yoshifumi,Inagaki, Shinji
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supporting information
p. 13007 - 13016
(2016/01/09)
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- A mild carbon-boron bond formation from diaryliodonium salts
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The direct metal-free borylation of diaryliodonium salts with diboron reagents is now demonstrated to be a feasible process toward formation of aryl boronic esters without any additive or catalysts, and it can be extended to a two-step C-C coupling of both aryl groups of the initial diaryliodonium reagent.
- Miralles,Romero,Fernández,Mu?iz
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p. 14068 - 14071
(2015/09/15)
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- Palladium-Catalyzed Monofluoromethylation of Arylboronic Esters with Fluoromethyl Iodide
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The first palladium-catalyzed direct monofluoromethylation of arylboronic esters to produce monofluoromethyl arenes is reported. The reaction is typically carried out at room temperature within 4 h and has a good functional group tolerance. The monofluoromethylating agent, CH2FI, was readily prepared via a halogen-exchange process.
- Hu, Jingyu,Gao, Bing,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 3086 - 3089
(2015/06/30)
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- Synthesis and antitumor activities evaluation of m-(4-morpholinoquinazolin-2-yl)benzamides in vitro and in vivo
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In the present study, a series of m-(4-morpholinoquinazolin-2-yl)benzamides were designed, synthesized and characterized. The antiproliferative activities of the synthesized compounds were evaluated against two human cell lines (HCT-116 and MCF-7). Compounds with IC50 values below 4 μM were further evaluated against U-87 MG and A549 cell lines. Among these evaluated compounds, compound T10 displayed a remarkable antiproliferative effect in vitro. The hoechst staining assay showed that compound T10 caused morphological changes. The cell cycle and apoptosis assay further indicated that compound T10 can arrest HCT-116 cells in G2/M and G0/G1 phase and induce apoptosis. PI3K enzyme assays indicated that compounds T7 and T10 selectively inhibit PI3K±. A Western bolt assay further suggested that compound T10 can block the PI3K/Akt/mTOR pathway. Moreover, compound T10 inhibited tumor growth on a mice S180 homograft model. These findings directly identify m-(4-morpholinoquinazolin-2-yl)benzamide derivatives as novel anticancer agents.
- Wang, Xiao-Meng,Xin, Min-Hang,Xu, Jing,Kang, Bo-Rui,Li, Yan,Lu, She-Min,Zhang, San-Qi
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p. 382 - 395
(2015/05/05)
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- Fluorine-controlled C-H borylation of arenes catalyzed by a PSiN-pincer platinum complex
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An efficient, regioselective synthesis of fluorine-substituted arylboronic esters was achieved through fluorine-controlled C-H borylation of arenes with diboron catalyzed by a PSiN-platinum complex. The promising utility of the PSiN-platinum catalyst and its unique regioselectivity were demonstrated for the first time, which would complement the well-developed Ir-catalyzed C-H borylation.
- Takaya, Jun,Ito, Shisei,Nomoto, Hironori,Saito, Narumasa,Kirai, Naohiro,Iwasawa, Nobuharu
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supporting information
p. 17662 - 17665
(2015/12/18)
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- "nok": A phytosterol-based amphiphile enabling transition-metal-catalyzed couplings in water at room temperature
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The third-generation designer amphiphile/surfactant, "Nok" (i.e., SPGS-550-M; β-sitosterol methoxypolyethyleneglycol succinate), soon to be commercially available from Aldrich, can be prepared in two steps using an abundant plant feedstock and β-sitosterol, together with succinic anhydride and PEG-550-M. Upon dissolution in water, it forms nanomicelles that serve as nanoreactors, which can be characterized by both cryo-TEM and dynamic light scattering analyses. Several transition-metal-catalyzed reactions have been run under micellar conditions to evaluate this surfactant relative to results obtained in nanoparticles composed of TPGS-750-M (i.e., a second-generation surfactant). It is shown that Nok usually affords yields that are, in general, as good or better than those typically obtained with TPGS-750-M, and yet is far less costly.
- Klumphu, Piyatida,Lipshutz, Bruce H.
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p. 888 - 900
(2014/03/21)
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- A solid chelating ligand: Periodic mesoporous organosilica containing 2,2′-bipyridine within the pore walls
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Synthesis of a solid chelating ligand for the formation of efficient heterogeneous catalysts is highly desired in the fields of organic transformation and solar energy conversion. Here, we report the surfactant-directed self-assembly of a novel periodic mesoporous organosilica (PMO) containing 2,2′-bipyridine (bpy) ligands within the framework (BPy-PMO) from a newly synthesized organosilane precursor [(i-PrO) 3Si-C10H6N2-Si(Oi-Pr)3] without addition of any other silane precursors. BPy-PMO had a unique pore-wall structure in which bipyridine groups were densely and regularly packed and exposed on the surface. The high coordination ability to metals was also preserved. Various bipyridine-based metal complexes were prepared using BPy-PMO as a solid chelating ligand such as Ru(bpy)2(BPy-PMO), Ir(ppy) 2(BPy-PMO) (ppy = 2-phenylpyridine), Ir(cod)(OMe)(BPy-PMO) (cod = 1,5-cyclooctadiene), Re(CO)3Cl(BPy-PMO), and Pd(OAc) 2(BPy-PMO). BPy-PMO showed excellent ligand properties for heterogeneous Ir-catalyzed direct C-H borylation of arenes, resulting in superior activity, durability, and recyclability to the homogeneous analogous Ir catalyst. An efficient photocatalytic hydrogen evolution system was also constructed by integration of a Ru-complex as a photosensitizer and platinum as a catalyst on the pore surface of BPy-PMO without any electron relay molecules. These results demonstrate the great potential of BPy-PMO as a solid chelating ligand and a useful integration platform for construction of efficient molecular-based heterogeneous catalysis systems.
- Waki, Minoru,Maegawa, Yoshifumi,Hara, Kenji,Goto, Yasutomo,Shirai, Soichi,Yamada, Yuri,Mizoshita, Norihiro,Tani, Takao,Chun, Wang-Jae,Muratsugu, Satoshi,Tada, Mizuki,Fukuoka, Atsushi,Inagaki, Shinji
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supporting information
p. 4003 - 4011
(2014/04/03)
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- Copper-mediated fluorination of arylboronate esters. Identification of a Copper(III) fluoride complex
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A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through arylboronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III), followed by rate-limiting transmetalation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS.
- Fier, Patrick S.,Luo, Jingwei,Hartwig, John F.
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supporting information
p. 2552 - 2559
(2013/03/29)
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- Internal Lewis acid assisted benzoic acid catalysis
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Internal Lewis acid assisted benzoic acid derivatives are introduced as new low-molecular-weight single-hydrogen-bond donor catalysts for the activation of nitroalkenes. Selected 2-borylbenzoic acid derivatives gave good yields of products in the addition of indoles to nitroalkenes. Control experiments suggest that both the internal Lewis acid coordination and the carboxylic acid functionalities are critical to the optimal performance of these catalysts. Georg Thieme Verlag Stuttgart New York.
- Auvil, Tyler J.,Mattson, Anita E.
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supporting information; experimental part
p. 2173 - 2180
(2012/09/22)
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- Carbon-boron bond cross-coupling reaction catalyzed by -PPh2 containing palladium-indolylphosphine complexes
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This study describes the application of indolylphosphine ligands with a diphenylphosphino moiety to the palladium-catalyzed borylation of aryl chlorides. The combination of palladium metal precursor with PPh 2-Andole-phos, which comprises an inexpensive -PPh2 group, provides highly effective catalysts for the borylation of aryl chlorides. A range of functional groups such as -CN, -NO2, -CHO, -COMe, -COOMe, and -CF3 was compatible, and the catalyst loading down to 0.025 mol % of Pd can be achieved. The Pd/PPh2-Andole-phos system is able to catalyze both borylation reaction and Suzuki-Miyaura coupling reaction in a one-pot sequential manner for the direct synthesis of biaryl compounds in excellent yields.
- Chow, Wing Kin,Yuen, On Ying,So, Chau Ming,Wong, Wing Tak,Kwong, Fuk Yee
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experimental part
p. 3543 - 3548
(2012/06/15)
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- Palladium-catalyzed borylation of aryl arenesulfonates with dialkoxyboranes
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The cross-coupling of aryl arenesulfonates with dialkoxyboranes proceeded in the presence of Bu4NI and a catalytic amount of [Pd(dba) 2]/1,1'-bis(di-tert-butylphosphano)ferrocene, giving good yields of the corresponding arylboronates. The protocols tolerate a wide range of functional groups, including ester, nitrile, and ketone.
- Murata, Miki,Oda, Takeshi,Sogabe, Yosuke,Tone, Hirofumi,Namikoshi, Takeshi,Watanabe, Shinji
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p. 962 - 963
(2011/12/05)
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- Targeting the heat shock protein 90 dimer with dimeric inhibitors
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The design, synthesis, and biological evaluation of conformationally constrained coumermycin A1 analogues are reported. Compounds were evaluated against both breast cancer (SKBr3 and MCF7) and prostate cancer (PC3 mm2, A549, and HT29) cell lines. Non-noviosylated coumermycin A1 analogues that manifest potent antiproliferative activity resulting from Hsp90 inhibition are provided, wherein replacement of the stereochemically complex noviose sugar with readily available piperidine rings resulted in ü100 fold increase in antiproliferative activities as compared to coumermycin A1, producing small molecule Hsp90 inhibitors that exhibit nanomolar activities.
- Kusuma, Bhaskar Reddy,Peterson, Laura B.,Zhao, Huiping,Vielhauer, George,Holzbeierlein, Jeffrey,Blagg, Brian S. J.
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experimental part
p. 6234 - 6253
(2011/10/31)
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- Palladium-catalyzed borylation of aryl mesylates and tosylates and their applications in one-pot sequential suzuki-miyaura biaryl synthesis
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Top of the one-pots! The first palladium-catalyzed borylation of aryl tosylates and mesylates is described. The reaction conditions are mild and provide excellent functional-group compatibility (e.g., R=CN, CHO, COOMe, C(O)R, NH2, or NH-indole; see scheme). Pd/MeO-CM-phos allows one-pot sequential reactions in the preparation of unsymmetrical biaryls. Copyright
- Chow, Wing Kin,So, Chau Ming,Lau, Chak Po,Kwong, Fuk Yee
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supporting information; experimental part
p. 6913 - 6917
(2011/08/03)
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- Ortho-C-H borylation of benzoate esters with bis(pinacolato)diboron catalyzed by iridium-phosphine complexes
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Iridium complexes generated from [Ir(OMe)(COD)]2 and tris[3,5-bis(trifluoromethyl)phenyl]phosphine efficiently catalyzed the ortho-C-H borylation of benzoate esters with bis(pinacolato)diboron in octane at 80 °C to produce the corresponding ary
- Ishiyama, Tatsuo,Isou, Hironori,Kikuchi, Takao,Miyaura, Norio
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p. 159 - 161
(2010/04/01)
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- Development of recyclable iridium catalyst for C-H borylation
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Aromatic C-H borylation using [IrCl(COD)]2 and 2,2′-bipyridinedicarboxylic acids was studied. 2,2′-Bipyridine-4,4′-dicarboxylic acid was complexed with [IrCl(COD)]2 in the presence of bis(pinacolato)diboron. The resulting iridium catalyst could be readily separated from the reaction mixture by simple filtration, and the recovered catalyst under a nitrogen atmosphere was still active and could be reused more than 10 times.
- Tagata, Tsuyoshi,Nishida, Mayumi,Nishida, Atsushi
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scheme or table
p. 6176 - 6179
(2009/12/26)
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- A 2-pyrone cycloaddition route to functionalised aromatic boronic esters
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A [4+2] cycloaddition/retro-cycloaddition route to functionalised aromatic boronic esters is outlined. A range of electron deficient dienes (2-pyrones) and dienophiles (alkynylboronates) were found to participate in the reaction. Furthermore, high levels
- Delaney, Patrick M.,Browne, Duncan L.,Adams, Harry,Plant, Andrew,Harrity, Joseph P.A.
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p. 866 - 873
(2008/09/16)
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- An alkynylboronic ester cycloaddition route to functionalised aromatic boronic esters
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A series of functionalised aromatic boronic esters have been prepared via the regioselective cycloaddition of 2-pyrones with alkynylboronates. The Royal Society of Chemistry 2006.
- Delaney, Patrick M.,Moore, Jane E.,Harrity, Joseph P. A.
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p. 3323 - 3325
(2008/09/19)
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