- Copper-Catalyzed Aerobic Oxidation of N-Pyridylindole Leading to Fused Quinazolinones
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Copper catalyzed aerobic oxidation enables the tandem selective and efficient transformation of N-pyridylindole for the construction of 11H-pyrido[2,1-b]quinazolin-11-ones. The reaction shows good efficiency to accomplish the aerobic oxidation. Mechanisti
- Ye, Yaqing,Yue, Yuanyuan,Guo, Xiaohui,Chao, Junli,Yang, Yan,Sun, Chunying,Lv, Qingzhang,Liu, Jianming
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- Transition-Metal-Free Synthesis of Fused Quinazolinones by Oxidative Cyclization of N-Pyridylindoles
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An unprecedented synthesis of fused quinazolinones from N-pyridylindoles under oxidative conditions using a combination of (diacetoxyiodo)benzene and K2S2O8 is reported. The reaction is metal-free, has a broad substrate scope, is operationally simple with short reaction time, and provides 11H-pyrido[2,1-b]quinazolin-11-one derivatives in moderate to high yields. It is believed to proceed via an in situ generated 2-hydroxy-1-(pyridin-2-yl)indolin-3-one as the key reaction intermediate, which undergoes a C-C bond cleavage to produce an electrophilic C-3 site in N-pyridyl indole. Subsequent nucleophilic attack by pyridyl nitrogen results in its cyclization.
- Garia, Alankrita,Jain, Nidhi
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- Elucidating the Mechanism of Aryl Aminations Mediated by NHC-Supported Nickel Complexes: Evidence for a Nonradical Ni(0)/Ni(II) Pathway
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Nickel catalysis is gaining in popularity in recent years, mostly within the area of cross-coupling. However, unlike Pd, the mechanisms of Ni-catalyzed C-C and C-heteroatom bond forming reactions have been much less studied, in particular when N-heterocyclic carbenes are used as ligands. Here, we present a thorough study of the mechanism of C-N cross-coupling reactions catalyzed by an NHC-Ni complex. Focusing on the coupling of 2-chloropyridines with indole catalyzed by [(IPrNi(styrene)2] (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), we have examined each of the elementary steps: i.e., oxidative addition, ligand substitution, and reductive elimination. All relevant catalytic intermediates have been isolated and structurally characterized by both spectroscopic and crystallographic methods. Kinetic studies have revealed that the reductive elimination is the rate-limiting step. Catalyst deactivation is related to the formation of unproductive dinuclear pyridyl-bridged NHC-NiII species, which can be prevented by increasing the size of the heteroaryl chloride. These investigations support a neutral Ni(0)/Ni(II) catalytic cycle. Calculations corroborate the experimental evidence and confirm the influence exerted by the ligands in each of the elementary steps.
- Rull, Silvia G.,Funes-Ardoiz, Ignacio,Maya, Celia,Maseras, Feliu,Fructos, Manuel R.,Belderrain, Tomás R.,Nicasio, M. Carmen
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- Ruthenium(II)-Catalyzed C-H Methylation with Trifluoroborates
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A cationic ruthenium(II)-complex enabled unprecedented C-H methylations on indoles and pyrroles. The versatile catalyst proved to be widely applicable and delivered the methylated heteroarenes with excellent levels of positional selectivity and ample substrate scope. The robustness of the catalysts was reflected by the challenging racemization-free C-H methylation of (S)-tryptophan.
- Tonin, Marlon Daniel Lima,Zell, Daniel,Müller, Valentin,Ackermann, Lutz
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- Controlling selectivity in N-heterocycle directed borylation of indoles
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Electrophilic borylation of indoles with BX3(X = Cl or Br) using directing groups installed at N1 can proceed at the C2 or the C7 position. The six membered heterocycle directing groups utilised herein, pyridines and pyrimidine, result in indole C2 borylation being the dominant outcome (in the absence of a C2-substituent). In contrast, C7 borylation was achieved using five membered heterocycle directing groups, such as thiazole and benzoxazole. Calculations on the borylation of indole substituted with a five (thiazole) and a six (pyrimidine) membered heterocycle directing group indicated that borylation proceedsviaborenium cations with arenium cation formation having the highest barrier in both cases. The C7 borylated isomer was calculated to be the thermodynamically favoured product with both five and six membered heterocycle directing groups, but for pyrimidine directed indole borylation the C2 product was calculated to be the kinetic product. This is in contrast to thiazole directed indole borylation with BCl3where the C7 borylated isomer is the kinetic product too. Thus, heterocycle ring size is a useful way to control C2vs. C7 selectivity in N-heterocycle directed indole C-H borylation.
- Iqbal,Yuan,Cid,Pahl,Ingleson
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- Method for oxidizing N-pyridine indoline compound by air
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The invention discloses a method for oxidizing an N-pyridine indoline compound by air. According to the method, a copper salt and N-hydroxyphthalimide are used as a common catalyst, air is used as anoxidizing agent, C2 and C3 sites of the N-pyridine indoline compound are dehydrogenated and oxidized in an organic solvent, and the N-pyridine indoline derivative is obtained. The method is simple inreaction operation and mild in condition, and has the advantages of low reaction cost, high yield and the like.
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Paragraph 0027-0034
(2021/01/24)
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- Manganese(III) Acetate Catalyzed Aerobic Dehydrogenation of Tertiary Indolines, Tetrahydroquinolines and an N-Unsubstituted Indoline
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A Mn(OAc)3 ? 2H2O-catalyzed aerobic dehydrogenation of five and six-membered N-heterocycles for the synthesis of N-heteroarenes is reported. Of note, this protocol can be applied to the dehydrogenation of tertiary indolines with various electron-deficient N-substituents. Preliminary mechanistic investigations support that a single-electron transfer pathway might be involved. (Figure presented.).
- Niu, Xiaokang,Yang, Lei
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supporting information
p. 4209 - 4215
(2021/08/06)
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- Functionalization of superparamagnetic Fe3O4@SiO2 nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst for N-arylation of α-amino acids and nitrogen-containing heterocycles with aryl halides
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Fe3O4@SiO2 nanoparticles was functionalized with a binuclear Schiff base Cu(II)-complex (Fe3O4@SiO2/Schiff base-Cu(II) NPs) and used as an effective magnetic hetereogeneous nanocatalyst for the N-arylation of α-amino acids and nitrogen-containig heterocycles. The catalyst, Fe3O4@SiO2/Schiff base-Cu(II) NPs, was characterized by Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) analyses step by step. Size, morphology, and size distribution of the nanocatalyst were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scatterings (DLS) analyses, respectively. The structure of Fe3O4 nanoparticles was checked by X-ray diffraction (XRD) technique. Furthermore, the magnetic properties of the nanocatalyst were investigated by vibrating sample magnetometer (VSM) analysis. Loading content as well as leaching amounts of copper supported by the catalyst was measured by inductive coupled plasma (ICP) analysis. Also, thermal studies of the nanocatalyst was studied by thermal gravimetric analysis (TGA) instrument. X-ray photoelectron spectroscopy (XPS) analysis of the catalyst revealed that the copper sites are in +2 oxidation state. The Fe3O4@SiO2/Schiff base-Cu(II) complex was found to be an effective catalyst for C–N cross-coupling reactions, which high to excellent yields were achieved for α-amino acids as well as N-hetereocyclic compounds. Easy recoverability of the catalyst by an external magnet, reusability up to eight runs without significant loss of activity, and its well stability during the reaction are among the other highlights of this catalyst.
- Sardarian,Kazemnejadi,Esmaeilpour
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- Ir(I)-Catalyzed C?H Glycosylation for Synthesis of 2-Indolyl-C-Deoxyglycosides
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The construction of 2-deoxy-C-glycosides has gradually become a hotspot of carbohydrate chemistry in recent years. In this work, we present an efficient, regioselective, stereoselective and widely applicable strategy for the synthesis of 2-indolyl-C-deoxyglycosides via Ir(I)-catalyzed, pyridine-group-directed C?H functionalization. This method exhibits high tolerance for the functional groups of indoles and the protecting groups of carbohydrates. Moreover, this protocol has good stereoselectivity and mainly produces β-configuration products. Gram-scale synthesis and several practical transformations were conducted for further applications. Meantime, we also explored the mechanism of this method and proposed a catalytic cycle. (Figure presented.).
- Yu, Changyue,Liu, Yichu,Xie, Xiong,Hu, Shulei,Zhang, Shurui,Zeng, Mingjie,Zhang, Dan,Wang, Jiang,Liu, Hong
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supporting information
p. 4926 - 4931
(2021/09/09)
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- Rhodium-Catalyzed Additive-Free C?H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate
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A rhodium-catalyzed C(sp2)-H ethoxycarbonylation of indoles and arylpyridines using diethyl dicarbonate was developed. The catalytic process features an additive-free ethoxycarbonylation reaction, in which only ethanol and CO2 are produced as byproducts, providing a CO-free and operationally simple protocol. The introduced ethoxycarbonyl group is easily transformed into other ester and amide functionalities in a single step. Moreover, the reaction can be successfully applied on gram scale, and allows for the efficient synthesis of indole-2-carboxylic acid esters and isophthalates.
- Suzuki, Hirotsugu,Liao, Yumeng,Kawai, Yuya,Matsuda, Takanori
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supporting information
p. 4938 - 4942
(2021/09/30)
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- Cp?Co(III)-Catalyzed enantioselective hydroarylation of unactivated terminal alkenes via C-H activation
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Enantioselective hydroarylation of unactivated terminal akenes constitutes a prominent challenge in organic chemistry. Herein, we reported a Cp*Co(III)-catalyzed asymmetric hydroarylation of unactivated aliphatic terminal alkenes assisted by a new type of tailor-made amino acid ligands. Critical to the chiral induction was the engaging of a novel noncovalent interaction (NCI), which has seldomly been disclosed in the C-H activation area, arising from the molecular recognition among the organocobalt(III) intermediate, the coordinated alkene, and the well-designed chiral ligand. A broad range of C2-alkylated indoles were obtained in high yields and excellent enantioselectivities. DFT calculations revealed the reaction mechanism and elucidated the origins of chiral induction in the stereodetermining alkene insertion step.
- Fan, Jun,Hong, Xin,Liu, Lei,Liu, Yan-Hua,Shi, Bing-Feng,Xie, Pei-Pei,Zhang, Zhuo-Zhuo
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supporting information
p. 19112 - 19120
(2021/11/26)
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- Iminyl-radicals by electrochemical decarboxylation of α-imino-oxy acids: construction of indole-fused polycyclics
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Iminyl radicals are reactive intermediates that can be used for the construction of various valuable heterocycles. Herein, the electrochemical decarboxylation of α-imino-oxy acids for the generation of iminyl radicals has been accomplished under exogenous-oxidant- and metal-free conditions through the use ofnBu4NBr as a mediator. The resulting iminyl radicals undergo intramolecular cyclization smoothly with the adjacent (hetero)arenes to afford a series of indole-fused polycyclic compounds.
- Wan, Jin-Lin,Cui, Jian-Feng,Zhong, Wei-Qiang,Huang, Jing-Mei
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supporting information
p. 10242 - 10245
(2021/10/12)
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- N-substituted aminobiphenyl palladacycles stabilized by dialkylterphenyl phosphanes: Preparation and applications in C[sbnd]N cross-coupling reactions
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Neutral and cationic N-methyl- and N-phenyl-2-aminobiphenyl methanesulfonate palladacycles stabilized with dialkylterphenyl phosphanes have been prepared and characterized. Neutral structures are favored with the less bulky phosphane PMe2ArXyl2, L1, while more sterically demanding ligands PiPr2ArXyl2, L3, and PCyp2ArXyl2 (Cyp = cyclopentyl), L4, lead to cationic complexes in which the phosphane exhibits a bidentate κ1-P, η1-Carene coordination mode involving one of the ipso carbon atoms of a flanking terphenyl aryl ring. The complexes were evaluated for activity in C[sbnd]N cross-coupling reactions and [Pd(N-methyl-2-aminobiphenyl)L4](OMs) (OMs = mesylate) was identified as the most efficient precatalyst, facilitating the coupling of aryl chlorides with secondary and primary amines and indoles.
- Monti, Andrea,Rama, Raquel J.,Gómez, Beatriz,Maya, Celia,álvarez, Eleuterio,Carmona, Ernesto,Nicasio, M. Carmen
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supporting information
(2021/01/19)
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- N -Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C-O bond activation enabled by a reusable and durable nickel(0) catalyst
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An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst. This new stable catalyst was prepared on Fe3O4@SiO2 modified by EDTA and investigated by FT-IR, EDX, TEM, XRD, DLS, FE-SEM, XPS, NMR, TGA, VSM, ICP and elemental analysis techniques. The reaction proceeded via carbon-oxygen bond cleavage of (hetero)aryl carbamates and sulfamates under simple and mild conditions without the use of any external ligands. This method demonstrated functional group tolerance in the N-arylation of various nitrogen-containing compounds as well as aliphatic amines, anilines, pyrroles, pyrazoles, imidazoles, indoles, and indazoles with good to excellent yields. Furthermore, the catalyst could be easily recovered by using an external magnetic field and directly reused at least six times without notable reduction in its activity. This journal is
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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p. 13266 - 13278
(2020/10/07)
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- Tridentate Nickel(II)-Catalyzed Chemodivergent C-H Functionalization and Cyclopropanation: Regioselective and Diastereoselective Access to Substituted Aromatic Heterocycles
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A Schiff-base nickel(II)-phosphene-catalyzed chemodivergent C-H functionalization and cyclopropanation of aromatic heterocycles is reported in moderate to excellent yields and very good regioselectivity and diastereoselectivity. The weak, noncovalent interaction between the phosphene ligand and Ni center facilitates the ligand dissociation, generating the electronically and coordinatively unsaturated active catalyst. The proposed mechanisms for the reported reactions are in good accord with the experimental results and theoretical calculations, providing a suitable model of stereocontrol for the cyclopropanation reaction.
- Nag, Ekta,Gorantla, Sai Manoj N. V. T.,Arumugam, Selvakumar,Kulkarni, Aditya,Mondal, Kartik Chandra,Roy, Sudipta
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supporting information
p. 6313 - 6318
(2020/09/02)
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- Cobalt-Catalyzed Enantioselective Hydroarylation of 1,6-Enynes
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An asymmetric hydroarylative cyclization of enynes involving a C-H bond cleavage is reported. The cobalt-catalyzed cascade generates three new bonds in an atom-economical fashion. The products were obtained in excellent yields and excellent enantioselectivities as single diastereo- and regioisomers. Preliminary mechanistic studies indicate that the reaction shows no intermolecular C-H crossover. This work highlights the potential of cobalt catalysis in C-H bond functionalization and enantioselective domino reactivity.
- Whyte, Andrew,Torelli, Alexa,Mirabi, Bijan,Prieto, Liher,Rodríguez, José F.,Lautens, Mark
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supporting information
p. 9510 - 9517
(2020/05/18)
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- Palladium-Catalyzed C-2 and C-3 Dual C-H Functionalization of Indoles: Synthesis of Fluorinated Isocryptolepine Analogues
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Here we report a protocol to synthesize diversiform fluorinated isocryptolepine analogues with potential biological activities in one step via directed C-2 and C-3 dual C-H functionalization of indoles. We also attempted to take into account fluorinated imidoyl chlorides as a novel kind of synthons in the directed C-H functionalization reactions. As a result, a variety of fluorinated isocryptolepine analogues were obtained in up to 96% yield. Moreover, we conducted control experiments to disclose the reaction mechanism.
- Chen, Chen,Wang, Yuebo,Shi, Xiaonan,Sun, Wan,Zhao, Jinghui,Zhu, Yan-Ping,Liu, Liying,Zhu, Bolin
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supporting information
p. 4097 - 4102
(2020/06/08)
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- The copper(ii)-catalyzed and oxidant-promoted regioselective C-2 difluoromethylation of indoles and pyrroles
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A novel and efficient approach for the highly selective C-2 difluoromethylation of indole derivatives was developed by using sodium difluoromethylsulfinate (HCF2SO2Na) as the source of difluoromethyl groups and a Cu(ii) complex as the catalyst. Various substrates were well tolerated in this transformation and the desired products were obtained in moderate to good yields. Moreover, the late-stage C-2 difluoromethylation of bioactive molecules containing an indole ring was achieved in good yields. Generally, this reaction features excellent functional group compatibility, broad substrate scope and excellent C-2 selectivity. This journal is
- Zhang, Dong,Fang, Zheng,Cai, Jinlin,Liu, Chengkou,He, Wei,Duan, Jindian,Qin, Ning,Yang, Zhao,Guo, Kai
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supporting information
p. 8119 - 8122
(2020/08/03)
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- Nickel-catalyzed reductive defunctionalization of esters in the absence of an external reductant: Activation of C-O bonds
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The nickel-catalyzed reductive cleavage of esters in the absence of an external reductant, which involves the cleavage of an inert acyl C-O bond in O-Alkyl esters is reported. Various groups, such as N-containing heterocycles, esters, amides, and even arene rings can function as a directing group.
- Iyori, Yasuaki,Takahashi, Kenjiro,Yamazaki, Ken,Ano, Yusuke,Chatani, Naoto
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p. 13610 - 13613
(2019/11/14)
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- Activation Relay on Rhodium-Catalyzed C-H Aminomethylation in Cooperation with Photoredox Catalysis
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A site selective C-H aminomethylation at indole's C3 position has been achieved by merging rhodium(III)-catalyzed C-H activation and photoredox catalysis in a one-pot manner. An investigation of the mechanistic insights rationalized the essence of the activation relay and the combination mode.
- Liu, Ruixing,Liu, Jiaxin,Wei, Yin,Shi, Min
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supporting information
p. 4077 - 4081
(2019/06/14)
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- ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
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Novel metal compounds having a first ligand LA that has the following formula: Formula I useful as emitters in OLED application are disclosed.
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Paragraph 0125
(2019/01/09)
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- Dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles as a novel recyclable catalyst for N-arylation of nitrogen heterocycles and green synthesis of 5-substituted 1H-tetrazoles
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In this study, dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles were prepared via a multistep-synthesis. Then, the synthesized composite was fully characterized by various techniques such as fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), UV-vis spectroscopy, energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA) and vibration sample magnetometer (VSM). From the information gained by. FE-SEM and TEM studies it can be inferred that the particles are mostly spherical in shape and have an average size of 50?nm. Also, the amount of Cu is determined to be 0.51?mmol/g in the catalyst by inductively coupled plasma (ICP) analyzer. This magnetic nano-compound has been successfully applied as a highly efficient, magnetically recoverable and stable catalyst for N-arylation of nitrogen heterocycles with aryl halides (I, Br) and arylboronic acids without using external ligands or additives. The catalyst was also employed in a one-pot, three-component reaction for the efficient and green synthesis of 5-substituted 1H-tetrazoles using various aldehydes, hydroxylamine hydrochloride and sodium azide in water. The magnetic catalyst can be easily separated by an external magnet bar and is recycled seven times without significant loss of its activity.
- Esmaeilpour, Mohsen,Sardarian, Ali Reza,Firouzabadi, Habib
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- Nonconventional difluoroalkylation of C(sp2)-H bonds through hydroarylation
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An unprecedented Rh-catalyzed C2-difluoroalkylation of indole derivatives with 2,2-difluorovinyl arenesulfonates has been reported. This reaction provides a rare instance of catalytic difluoroalkylation through hydroarylation of gem-difluoroalkenes. The sulfonate group works as a chelating ligand, thus stabilizing the rhodacycle intermediate, leading to the uncommon transformation.
- Zhu, Chuan,Song, Shengjin,Zhou, Lu,Wang, Ding-Xing,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 9482 - 9485
(2017/09/01)
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- Rhodium-catalyzed C-H functionalization with N-acylsaccharins
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A rhodium-catalyzed C-H functionalization with activated amides by decarbonylation has been developed. Notably, this is the first C-H arylation employing N-acylsaccharins as coupling partners to give biaryls in good to excellent yields. The highlight of the work is the high tolerance of functional groups such as formyl, ester, and vinyl and the use of a removable directing group.
- Wu, Hongxiang,Liu, Tingting,Cui, Ming,Li, Yue,Jian, Junsheng,Wang, Hui,Zeng, Zhuo
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supporting information
p. 536 - 540
(2017/01/25)
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- Nitroarenes as the Nitrogen Source in Intermolecular Palladium-Catalyzed Aryl C–H Bond Aminocarbonylation Reactions
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A three-component palladium-catalyzed aminocarbonylation of aryl and heteroaryl sp2 C?H bonds using nitroarenes as the nitrogen source was achieved using Mo(CO)6 as the reductant and origin of the CO. This intermolecular C?H bond functionalization does not requires any exogenous ligand to be added, and our mechanism experiments indicate that the palladacycle catalyst serves two roles in the aminocarbonylation reaction: reduce the nitroarene to a nitrosoarene and activate the sp2 C?H bond.
- Zhou, Fei,Wang, Duo-Sheng,Guan, Xinyu,Driver, Tom G.
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supporting information
p. 4530 - 4534
(2017/04/11)
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- Phosphine-functionalized NHC Ni(II) and Ni(0) complexes: Synthesis, characterization and catalytic properties
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Two families of nickel complexes bearing chelating diphenylphosphine-functionalized NHC ligands [NiII(ArNHCPPh2)(allyl)]Cl 1a (Ar = Mes); 1b, (Ar = 2,6-iPr2-C6H3) and [Ni0(ArNHCPPh2)(alkene)] 2a (Ar = 2,6-iPr2-C6H3, alkene = styrene); 2b (Ar = 2,6-iPr2-C6H3, alkene = diethyl fumarate) have been prepared and fully characterized. VT-NMR experiments in solution reveal that the allyl derivatives 1a-b are stereochemically nonrigid. The solid-state structure of the Ni0 derivative 2b is also reported. These complexes display interesting catalytic properties in various cross-coupling reactions. The precatalyst [Ni0(ArNHCPPh2)(styrene)] 2a was found to be the most active system. The bulkiness of the N-substituent on the imidazole ring and the low oxidation state of the metal center in 2a accounted for its enhanced catalytic performance. This system catalyzed effectively the coupling of (hetero)aryl chlorides with a range of nucleophiles including Grignard reagents, boronic acids, secondary amines and indoles.
- Rull,Rama,álvarez,Fructos,Belderrain,Nicasio
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supporting information
p. 7603 - 7611
(2017/07/10)
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- 1,4-Dihydroxyanthraquinone-copper(II) supported on superparamagnetic Fe3O4@SiO2: An efficient catalyst for N -arylation of nitrogen heterocycles and alkylamines with aryl halides and click synthesis of 1-aryl-1,2,3-triazole derivatives
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1,4-Dihydroxyanthraquinone-copper(ii) supported on a superparamagnetic Fe3O4@SiO2 catalyst was employed for the N-arylation of nitrogen heterocycles and alkylamines with aryl halides to afford the corresponding coupled products in good to excellent yields without using external ligands or additives as promoters. Also, we have reported this recyclable catalytic system for efficient synthesis of 1-aryl-1,2,3-triazole derivatives in excellent yields. The desired triazoles were obtained from the reaction of the corresponding aryl boronic acid derivatives, alkyne, NaN3, and 0.5 mol% catalyst in water/acetonitrile as the solvent at room temperature without the additional use of an external reducing agent. These methods show notable advantages such as the heterogeneous nature of the catalyst, low catalyst loading, easy preparation, excellent yields, short reaction times and simplicity of operation. Also, the catalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused in six consecutive reaction cycles without significant loss of activity.
- Zahmatkesh, Saeed,Esmaeilpour, Mohsen,Javidi, Jaber
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p. 90154 - 90164
(2016/10/09)
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- Diversification of Indoles via Microwave-assisted Ligand-free Copper-catalyzed N-Arylation
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A simple, efficient Cu2O catalyst system under microwave irradiation was developed for N-arylation of various indoles without ligands and additives. Diverse N-heteroarylated indoles were prepared by coupling indoles with various heteroaryl hali
- Kwon, Jae-Kwan,Lee, Jin -Hee,Kim, Tae Sung,Yum, Eul Kgun,Park, Hee Jung
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p. 1927 - 1933
(2016/12/16)
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- Palladium-catalysed direct C-2 methylation of indoles
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A direct C-2 methylation reaction of indoles bearing a readily removable N-2-pyrimidyl moiety as a site-specific directing group has been developed with a palladium catalyst. This reaction relied on the use of KF to promote efficient methylation. A moderate to good yield was achieved in a range of indole substrates.
- Tu, Daoquan,Cheng, Xiuzhi,Gao, Yadong,Yang, Panpan,Ding, Yousong,Jiang, Chao
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supporting information
p. 7443 - 7446
(2016/08/16)
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- Cp?CoIII-Catalyzed Synthesis of Pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-iums via Tandem C-H Activation and Subsequent Annulation from 1-(Pyridin-2-yl)-1H-indoles and Internal Alkynes
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A Cp?CoIII-catalyzed C2-selective C-H alkenylation/annulation cascade transformation of 1-(pyridin-2-yl)-1H-indoles with internal alkynes to afford pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-iums is presented. Moreover, 6,7-dihydro-4H-pyrido[2′,1′:2,3]pyrimido[1,6-a]indole, a new functionalized N-fused indole core heterocycle, could be constructed effectively via reduction of pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-ium by NaBH4.
- Yang, Yuhan,Li, Bo,Liu, Wenmin,Zhang, Rumeng,Yu, Lintao,Ma, Qin-Ge,Lv, Rongrong,Du, Donghua,Li, Ting
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p. 11335 - 11345
(2016/11/29)
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- Cobalt-catalyzed C-H cyanation of (Hetero)arenes and 6-Arylpurines with N -cyanosuccinimide as a new cyanating agent
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A cobalt-catalyzed C-H cyanation reaction of arenes has been developed using N-cyanosuccinimide as a new electrophilic cyanating agent. The reaction proceeds with high selectivity to afford monocyanated products with excellent functional group tolerance. Substrate scope was found to be broad enough to include a wide range of heterocycles including 6-arylpurines.
- Pawar, Amit B.,Chang, Sukbok
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supporting information
p. 660 - 663
(2015/03/04)
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- Ruthenium-catalyzed heteroatom-directed regioselective C-H arylation of indoles using a removable tether
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A new approach to C-2 arylated indoles has been developed by utilizing a ruthenium-catalyzed, heteroatom-directed regioselective C-H arylation. The reaction is highly site-selective and results in very good yields. The highlight of the work is the use of a removable directing group and compatibility of the catalytic system with halogen functional groups in the substrates.
- Tiwari, Virendra Kumar,Kamal, Neha,Kapur, Manmohan
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supporting information
p. 1766 - 1769
(2015/04/14)
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- 2-Phenyl-2-(4-phenyl-1 H-1,2,3-triazol-1-yl)ethanol as an efficient and versatile auxiliary ligand in copper(II)-catalyzed Buchwald-Hartwig and Sharpless-Meldal C-N bond-forming reactions
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A highly active, air-stable, and versatile procedure for Buchwald-Hartwig and Sharpless-Meldal C-N bond formation is reported. Under nearly solvent-free conditions using copper(II) acetate and 2-phenyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)ethanol, a variety of N-heterocycles and various cyclic and noncyclic secondary amines were arylated to form N-aryl compounds in moderate to excellent yields. This methodology also provides rapid access to diverse 1,4-disubstituted 1,2,3-triazoles in good to excellent yields. All reactions are performed in short times under air.
- Sharghi, Hashem,Shiri, Pezhman
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p. 1131 - 1146
(2015/04/14)
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- Rh/Cu-catalyzed multiple C-H, C-C, and C-N bond cleavage: Facile synthesis of pyrido[2,1-a]indoles from 1-(pyridin-2-yl)-1H-indoles and γ-substituted propargyl alcohols
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An unusual Rh/Cu-catalyzed synthesis of pyrido[2,1-a]indoles starting from 1-(pyridin-2-yl)-1H-indoles and γ-substituted propargyl alcohols was presented. The multi-step cascade transformations formally involve the cleavage of two C-H, three C-C, and one C-N bonds with concomitant construction of two C-H, four C-C, and one C-N bonds with excellent chemoselectivity in one-pot reaction.
- Li, Ting,Wang, Zhen,Zhang, Mingliang,Zhang, Hui-Jun,Wen, Ting-Bin
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supporting information
p. 6777 - 6780
(2015/04/22)
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- C-N coupling of indoles and carbazoles with aromatic chlorides catalyzed by a single-component NHC-nickel(0) precursor
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A new and efficient nickel-based protocol for the N-arylation of indoles and carbazoles with aromatic chlorides, the least expensive of the aryl halides, is described. The procedure provides selectively N-(hetero)arylation products in good to high yields, in short reaction times and without adding an excess of ligands.
- Rull, Silvia G.,Blandez, Juan F.,Fructos, Manuel R.,Belderrain, Tomás R.,Nicasio, M. Carmen
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supporting information
p. 907 - 911
(2015/03/30)
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- Rhodium-catalyzed regioselective direct C-H arylation of indoles with aryl boronic acids
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A highly efficient Rh(III)-catalyzed direct C-H arylation of indoles with aryl boronic acids under mild conditions has been developed. The methodology features wide substrate scope and excellent functional group compatibility (34 examples, up to 99% yield). The arylated products can also be conveniently transformed into biologically active polycyclic indole derivatives.
- Wang, Liang,Qu, Xing,Li, Zhan,Peng, Wang-Ming
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supporting information
p. 3754 - 3757
(2015/06/08)
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- Palladium on carbon-catalyzed one-pot N-arylindole synthesis: Intramolecular aromatic amination, aromatization, and intermolecular aromatic amination
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Indole and indoline derivatives were selectively and temperature dependently synthesized via the intramolecular cross-coupling reaction between the amino and aromatic bromine functionalities of 2-bromophenethylamine derivatives in the presence of 10% palladium on carbon (Pd/C), 1,1-bis(diphenylphosphino)ferrocene (DPPF), and sodium tert-butoxide (NaO-t-Bu) in mesitylene at 140 and 200°C, respectively. The neutralization using acetic acid after formation of the indoline derivatives effectively promoted their aromatization, and the corresponding indole derivatives were obtained at 140°C. Furthermore, various aryl groups were also introduced to the N-1 position of the indole, pyrrole, and carbazole rings by their direct intramolecular arylation with aryl halides and a one-pot protocol for N-arylindole synthesis from 2-bromophenethylamine was developed.
- Monguchi, Yasunari,Marumoto, Takahisa,Takamatsu, Haruki,Sawama, Yoshinari,Sajiki, Hironao
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p. 1866 - 1872
(2014/06/09)
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- Ceria-supported copper nanoparticles: A highly efficient and recyclable catalyst for N-arylation of indole
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CuCeO2 catalytic nanomaterials have been synthesized by impregnation of ceria by copper acetate, followed by reduction and calcination under nitrogen. The components of these nanomaterials were characterized by means of XRD, XPS, N2
- Amadine, Othmane,Maati, Houda,Abdelouhadi, Karima,Fihri, Aziz,El Kazzouli, Sa?d,Len, Christophe,El Bouari, Abdeslam,Solhy, Abderrahim
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p. 409 - 419
(2015/01/09)
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- Electrospun copper oxide nanoparticles as an efficient heterogeneous catalyst for N-arylation of indole
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The N-arylation of indoles with a variety of aryl bromides is reported using copper oxide nanoparticles as a heterogeneous catalyst. These copper oxide nanoparticles, which were produced in a novel, facile, and scalable fashion via an electrospinning tech
- Khalil, Abdullah,Fihri, Aziz,Jouiad, Mustapha,Hashaikeh, Raed
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p. 5973 - 5975
(2014/12/12)
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- BippyPhos: A single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides
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Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/ [Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl] 2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho- alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.
- Crawford, Sarah M.,Lavery, Christopher B.,Stradiotto, Mark
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supporting information
p. 16760 - 16771
(2014/01/06)
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- CuI/8-hydroxyquinalidine promoted N-arylation of indole and azoles
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An efficient catalytic system of CuI/8-hydroxyquinalidine was developed for the coupling of aryl iodides and indole as well as some azoles. The reaction could be carried out at 90°C under the condition of relatively low catalyst loading, affording various
- Zhang, Yihua,Yang, Xinye,Xing, Hui,Zhang, Ye,Lai, Yisheng,Jiang, Yongwen,Ma, Dawei
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experimental part
p. 875 - 880
(2012/05/21)
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- Palladium-assisted regioselective C-H cyanation of heteroarenes using isonitrile as cyanide source
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A palladium-catalyzed regioselective C-H cyanation of heteroarenes was achieved using tert-butyl isocyanide as "CN" source, which provides a new and unique strategy for the preparation of (hetero)aryl nitriles. Indoles, pyrroles, and aromatic rings could be efficiently cyanated through C-H bond activation with high regioselectivity.
- Xu, Shuguang,Huang, Xiaomei,Hong, Xiaohu,Xu, Bin
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supporting information
p. 4614 - 4617
(2012/11/06)
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- Benzotriazol-1-ylmethanol: An excellent bidentate ligand for the copper/palladium-catalyzed C-N and C-C coupling reaction
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An efficient benzotriazole based N,O bidentate ligands for the Cu-catalyzed N-arylation of π-excessive nitrogen heterocycles is described. This ligand accomplishes C-N coupling of Nheterocycles and C-C coupling of boronic acids with a variety of hindered, functionalized aryl/heteroaryl halides under mild reaction conditions in good to excellent yields. Using his ligand C-N and C-C (Suzuki) couplings with bromoarenes could be conducted with less catalyst loading. A wide array of deactivated and hindered aryl halides react cleanly to afford the functionalized biaryl derivatives in high yields. ARKAT-USA, Inc.
- Jha, Rajeev R.,Singh, Jaspal,Tiwari, Rakesh K.,Verma, Akhilesh K.
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p. 228 - 248
(2013/02/23)
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- Use of acylhydrazine- and acylhydrazone-type ligands to promote CuI-catalyzed C-N cross-coupling reactions of aryl bromides with N-heterocycles
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A series of ten acylhydrazine- and acylhydrazone-type ligands were designed and synthesized. Their electronic and steric properties were easily modified and tuned by varying the substituents in the vicinity of the acylhydrazine and acylhydrazone units. The effect of ligands on the catalytic activity of Ullmann reactions was assessed by using a combination of these ligands with CuI. The catalytic system is very efficient for the C-N coupling reaction of azoles with aryl and heteroaryl bromides. A simple and efficient procedure for copper-catalyzed C-N cross-coupling reactions between aryl bromides and NH-containingheterocycles is illustrated. Readily available acylhydrazine- and acylhydrazone-typeligands promote the reaction.
- Li, Liuyi,Zhu, Lei,Chen, Dagui,Hu, Xuelei,Wang, Ruihu
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experimental part
p. 2692 - 2696
(2011/06/25)
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- Transition-metal-free O-,S -, and N-arylation of alcohols, thiols, amides, amines, and related heterocycles
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A new protocol for the Ullmann-type arylation process of different aromatic heterocycles without any transition-metal catalyst, implying the use of a combination of an excess of potassium hydroxide and dimethyl sulfoxide, is described. The reaction can be performed between a broad range of starting nucleophiles including phenol, alcohols, amines, nitrogen-containing five-membered systems such as pyrazoles, imidazoles, and indoles, and amides with haloarenes, iodide and bromide derivatives giving the best results, the possible pathway involving the in situ generation of the corresponding benzyne intermediate. When the reaction was performed with 2-iodoaniline and either carboxamides or isothiocyanato derivatives, the corresponding benzoazole derivatives were obtained.
- Cano, Rafael,Ramon, Diego J.,Yus, Miguel
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experimental part
p. 654 - 660
(2011/03/20)
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- Ruthenium-catalyzed direct C-H bond arylations of heteroarenes
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Ruthenium-catalyzed C-H bond arylations of indoles, thiophenes, and pyrroles were accomplished in a highly chemo- and site-selective manner through the use of removable directing groups.
- Ackermann, Lutz,Lygin, Alexander V.
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supporting information; experimental part
p. 3332 - 3335
(2011/09/12)
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- Discovery and optimization of a new class of potent and non-chiral indole-3-carboxamide-based renin inhibitors
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Selective inhibition of the aspartyl protease renin has gained attraction as an interesting approach to control hypertension and associated cardiovascular risk factors given its unique position in the renin-angiotensin system. Using a combination of high-throughput screening, parallel synthesis, X-ray crystallography and structure-based design, we identified and optimized a novel series of potent and non-chiral indole-3-carboxamides with remarkable potency for renin. The most potent compound 5k displays an IC50 value of 2 nM.
- Scheiper, Bodo,Matter, Hans,Steinhagen, Henning,Stilz, Ulrich,B?cskei, Zsolt,Fleury, Valérie,McCort, Gary
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scheme or table
p. 6268 - 6272
(2010/11/18)
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- Pd-catalyzed C-N bond formation with heteroaromatic tosylates
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A protocol for the palladium(0)-catalyzed amidation of heteroaromatic tosylates was successfully developed. The methodology proved to be effective for a variety of heteroaryl tosylates including the pyridine, pyrimidine, quinoline and quinoxaline ring systems. Successful carbon-nitrogen bond formation with these heteroaryl tosylates could be performed with a wide range of primary amides, oxazolidinones, lactams, anilines and indoles, including one cyclic urea. Moreover, this C-N bond forming reaction provided products with high structural diversity. The coupling reaction was also amenable to scale up applications.
- Mantel, Mette L. H.,Lindhardt, Anders T.,Lupp, Daniel,Skrydstrup, Troeis
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supporting information; experimental part
p. 5437 - 5442
(2010/09/18)
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- Steric and electronic influence on photochromic switching of N,C-chelate four-coordinate organoboron compounds
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A four-coordinate organoboron compound B(ppy)Mes2 (1, ppy = 2-phenylpyridyl, Mes=mesityl) was previously found to undergo reversible photochromic switching through the formation/breaking of a C-C bond, accompanied by a dramatic color change fro
- Amarne, Hazem,Baik, Chul,Murphy, Stephen K.,Wang, Suning
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scheme or table
p. 4750 - 4761
(2010/09/05)
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- Benzotriazole: an efficient ligand for the copper-catalyzed N-arylation of indoles
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A general, efficient, and inexpensive method for the N-arylation of indoles using a catalytic system derived from CuI and benzotriazole is reported. Selective mono N-arylation of indoles with ortho-dihaloarenes has also been successfully achieved in good yields using this protocol.
- Verma, Akhilesh Kumar,Singh, Jaspal,Larock, Richard C.
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scheme or table
p. 8434 - 8439
(2009/12/26)
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