- Reaction of Halogenonitrobenzenes with Electro-generated Superoxide Ion
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The reaction of halogenonitrobenzenes (XNBs) with electrogenerated superoxide ion in N,N-dimethylformamide was studied electrochemically using cyclic voltammetry (CV) and controlled potential macro-electrolysis.It was shown in the CV that electro-generated superoxide ion reacts with all the o-and p-imorers of iodo-, bromo-, and chloronitrobenzene in the dissolved oxygen medium.However the superoxide ion did not react with the other XNBs during CV.Controlled potential macro-electrolysis of oxygen in the presence of o- and p-bromo-nitrobenzene yielded the corresponding nitriphenols as the main products.The reaction mechanism via nucleophilic attack of the superoxide ion on the XNB, in the preference to an electron-transfer mechanism, is proposed.
- Sagae, Hiromitsu,Fujihira, Masamichi,Komazawa, Katsutaro,Lund, Henning,Osa, Tetsuo
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- Intermediacy of Copper(I) under Oxidative Conditions in the Aerobic Copper-Catalyzed Decarboxylative Thiolation of Benzoic Acids
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An experimental mechanistic study of the aerobic copper-catalyzed decarboxylative thiolation of benzoic acids with arenethiols is reported. For the model reaction, the findings support the corresponding disulfide (PhSSPh) of the arenethiol (PhSH) as the active thiolating source under reaction conditions. Synthesis and reactivity studies along with kinetic measurements support the chemical and kinetic competence of catalytically active well-defined Cu complexes: (phen)CuI(O2CC6H4-o-NO2) (2), [(phen)CuI(μ-SC6H5)]2 (3), (phen)CuI(C6H4-o-NO2) (4), and (phen)CuII(O2CC6H4-o-NO2)2 (5) (phen = 1,10-phenanthroline). The presence of an induction period in the stoichiometric reaction of the copper(II) complex (phen)CuII(O2CC6H4-o-NO2)2 (5) with PhSSPh and the absence of an induction period in the analogous stoichiometric reaction of the copper(I) complex (phen)CuI(O2CC6H4-o-NO2) (2) suggest that a copper(I) carboxylate is a more likely intermediate than a copper(II) carboxylate. The observation of in situ reduction of CuII to CuI further supports CuI as the primary active catalytic species, and spectroscopic studies also indicate the catalyst resting state to be a CuI species. The catalytic reaction exhibits a first-order dependence on [CuI] and [2-nitrobenzoic acid] and a zero-order dependence on [PhSSPh] and p(O2), suggestive of turnover-limiting decarboxylation of a copper(I) carboxylate. Oxygen was found to promote the essential oxidative cleavage of the copper(I) thiolate intermediate [(phen)CuI(μ-SC6H5)]2 (3) to regenerate a catalytically active [(phen)CuII] (Cuox) species with concomitant formation of PhSSPh. On the basis of these findings, a reaction pathway is proposed for the C-S coupling reaction that includes the key CuI-based intermediates (phen)CuI(O2CC6H4-o-NO2) (2) and (phen)CuI(C6H4-o-NO2) (4). The pathway accounts for the role of O2 in generating the active thiolating source, PhSSPh, as well as enabling catalytic turnover of in situ generated [(phen)CuI(μ-SC6H5)]2 (3).
- Green, Kerry-Ann,Hoover, Jessica M.
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- Copper mediated decarboxylative direct C-H arylation of heteroarenes with benzoic acids
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Decarboxylative coupling reactions to date require a stoichiometric oxidant (such as copper and silver salts) for decarboxylation purposes along with a metal catalyst (e.g. palladium) for cross-coupling. In this communication, an economic and sustainable approach by using a simple copper salt was developed in the presence of molecular oxygen as the sole oxidant. A wide range of 5-membered heteroarenes undergo aryl-heteroaryl cross-coupling with electron deficient aryl carboxylic acids.
- Patra, Tuhin,Nandi, Sudip,Sahoo, Santosh K.,Maiti, Debabrata
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- Facile synthesis of 2,2′-dinitrosubstituted biaryls through Cu-catalyzed ligand-free decarboxylative homocoupling of ortho-nitrobenzoic acids
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A novel waste-free Cu-catalyzed decarboxylative homocoupling of ortho-nitrobenzoic acids has been developed, and diverse substituents on the phenyl core of ortho-nitrobenzoic acid are compatible with the transformation. This method provides a practical alternative to synthesize valuable 2,2′-dinitrosubstituted biaryls from cheap and readily available ortho-nitrobenzoic acids.
- Fu, Zhengjiang,Li, Zhaojie,Xiong, Qiheng,Cai, Hu
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Read Online
- 4-bromo-9H-carbazole synthesizing method
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The invention discloses a 4-bromo-9H-carbazole synthesizing method and belongs to the field of organic synthesis. According to the method, o-chloronitrobenzene is utilized as a starting material, 2,2'-dinitrobiphenyl is synthesized through high-temperature coupling reaction under copper powder catalysis, then 4-nitro carbazole is obtained through triethyl phosphite ring closure reaction, diazoniumsalt is prepared from 4-nitro carbazole through zinc powder reduction and diazotization reaction under the acid condition, and then the diazonium salt reacts with cuprous bromide to synthesize a product of 4-bromo-9H-carbazole. According to the method, the raw materials are easy to obtain, the production cost is low, and the yield can reach 70% or more; the method has easiness in industrial production and provides basis for industrialization of 4-bromo-9H-carbazole and follow-up derivatives of 4-bromo-9H-carbazole.
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Paragraph 0019-0021; 0024; 0025; 0028; 0029
(2019/02/04)
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- Synthetic method of 4-bromocarbazole
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The invention relates to a synthesis method of 4-bromocarbazole, which belongs to the field of organic synthesis. The method adopts o-chloronitrobenzene as an initial raw material to make high-temperature coupling reaction under the catalysis of copper powder to synthesize 2,2'-dinitrobipheny, then ring closing is performed by virtue of triethyl phosphite to obtain 4-nitrocarbazole, the 4-nitrocarbazole is subjected to reduction and diazotization reaction by virtue of zinc powder under the acidic condition to obtain diazonium salt, and the diazonium salt reacts with cuprous bromide to synthesize the product 4-bromocarbazole. The method adopts the easy-to-obtain raw materials, the production cost is low, the yield is 70 percent or above, the industrialized production is easy to implement, and a foundation is provided for the industrialization of the 4-bromocarbazole and subsequent derivatives thereof.
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Paragraph 0010; 0025-0026; 0029-0030; 0033-0034
(2019/02/04)
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- Decarboxylative ipso Amination of Activated Benzoic Acids
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In the presence of a bimetallic Pd/Cu system with 1,10-phenanthroline as the ligand and either air or N-methylmorpholine N-oxide as the oxidant, electron-deficient benzoic acids undergo oxidative decarboxylative coupling with unprotected amines. This operationally simple aniline synthesis is widely applicable with respect to the amine and gives good yields, even on multigram scale. The orthogonality of this reaction to other Pd-catalyzed cross-couplings allows the concise synthesis of multisubstituted arenes by sequential C?C, C?Cl, and C?N functionalizations. Mechanistic investigations suggest the intermediacy of a hypervalent Pd species.
- Pichette Drapeau, Martin,Bahri, Janet,Lichte, Dominik,Goo?en, Lukas J.
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supporting information
p. 892 - 896
(2019/01/04)
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- A Predictive Model for the Decarboxylation of Silver Benzoate Complexes Relevant to Decarboxylative Coupling Reactions
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Decarboxylative coupling reactions offer an attractive route to generate functionalized arenes from simple and readily available carboxylic acid coupling partners, yet they are underutilized due to limitations in the scope of carboxylic acid coupling partner. Here we report that the field effect parameter (F) has a substantial influence on the rate of decarboxylation of well-defined silver benzoate complexes. This finding provides the opportunity to surpass current substrate limitations associated with decarboxylation and to enable widespread utilization of decarboxylative coupling reactions.
- Crovak, Robert A.,Hoover, Jessica M.
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p. 2434 - 2437
(2018/02/28)
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- Synthesis of Aryl Alkynes via Copper Catalyzed Decarboxylative Alkynylation of 2-Nitrobenzoic Acids
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An efficient protocol for the synthesis of internal aryl alkynes was achieved via Cu-catalyzed decarboxylative cross-coupling reactions, and to the best of our knowledge, this is the first example of a Cu-catalyzed decarboxylative alkynylation of benzoic acids with terminal alkynes. This approach utilizes simple Cu salt as catalyst and O2, an abundant, clean, and green material, as the oxidant. The reaction tolerates various functional groups, and a variety of internal aryl alkynes were synthesized in 46-83% yields.
- Yu, Yongqi,Chen, Xiang,Wu, Qianlong,Liu, Da,Hu, Liang,Yu, Lin,Tan, Ze,Gui, Qingwen,Zhu, Gangguo
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p. 8556 - 8566
(2018/06/29)
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- Palladium-catalyzed reductive homocoupling of aryl sulfonates via cleavage of C─O bond at room temperature
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Palladium-catalyzed reductive homocoupling of aryl sulfonates has been successfully achieved under mild conditions. This transformation is a new method for the homocoupling reaction of aryl sulfonates at room temperature via the cleavage of C─O bonds, thus providing an alternative synthesis of symmetric biaryls. The reported reductive homocoupling reaction is tolerant of many common functional groups regardless of electron-donating or electron-withdrawing nature, making this newly developed transformation important for complementing Ullmann coupling. Experimental Section. Typical procedure for the products.
- Zhong, Shuangling,Chen, Mengxin,Liu, Ge,Sun, Chenggang,Liu, Wencong
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- Copper-free palladium-catalysed desulfinative homocoupling of sodium arylsulfinates under mild and aerobic conditions
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A Pd(II)-catalysed homocoupling of sodium arylsulfinates has been successfully achieved under mild conditions. This transformation is a new method for the homocoupling reaction of sodium arylsulfinates, thus providing an alternative synthesis of symmetric biaryls. The reported homocoupling reaction is tolerant to many common functional groups, such as ester, halo, cyano and nitro and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported desulfinative homocoupling does not require Cu salts, ligands and bases, making this newly developed transformation attractive.
- Zhang, Wei
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- An effective and environment-friendly system for Cu NPs@RGO-catalyzed C-C homocoupling of aryl halides or arylboronic acids in ionic liquids under microwave irradiation
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As an outstanding mesh catalyst support, reduced graphene oxide (RGO) has attracted enormous attention in recent years. Cu nanoparticles-RGO (Cu NPs@RGO) as a green catalyst was prepared through a green reduction method by ascorbic acid in N-methyl-2-pyrrolidone. The structure of prepared Cu NPs@RGO was characterized. The catalytic activity of Cu NPs@RGO was estimated. A green and efficient method for synthesizing symmetrical biaryl compounds was developed by Cu NPs@RGO-catalyzed Ullmann homocoupling of aryl halides or arylboronic acids in ionic liquids under microwave (MW) irradiation. The catalytic system could be recycled five times with slight loss of activity. Through this method, nine kinds of biaryls were prepared by homocoupling reaction of the corresponding aryl iodides, aryl bromides, aryl chlorides and aryl boronic acids in moderate to good yields.
- Zhao, Hongyan,Mao, Guijie,Han, Huatao,Song, Jinyi,Liu, Yang,Chu, Wenyi,Sun, Zhizhong
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p. 41108 - 41113
(2016/05/19)
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- A modified Cu(0)-Cu(I)-mediated Caryl-CarylUllmann coupling for the synthesis of biaryls
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A novel Cu(0)-Cu(I)-mediated Caryl-CarylUllmann coupling has been successfully developed. The use of Cu(I) salts allowed the reactions to proceed under relatively mild conditions (65?°C in DMSO for 15–72?h). The developed method was compatible with a relatively wide range of functional groups simultaneously present on the aromatic ring of different electronic nature. The aryl halides with an electron-withdrawing group ortho to the halide or an electron-donating group meta or para to the halide furnished the corresponding products in good to excellent yields (up to 98%).
- Yasamut, Kittisak,Jongcharoenkamol, Jira,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 5994 - 6000
(2016/09/14)
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- Pd(OAc)2 catalyzed homocoupling of arenediazonium salts in ionic liquids: Synthesis of symmetrical biaryls
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A facile, high yielding, and simple method for the synthesis of a library of symmetrical biaryls by homocoupling of arenediazonium salts is reported, employing catalytic amounts of Pd(OAc)2 and the readily available imidazolium ionic liquids (ILs), without oxidants, ligands, additives, or volatile solvents. Simple product isolation and recycling/reuse of the IL represent additional advantages of this method.
- Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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p. 663 - 667
(2016/01/26)
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- COMPOUND, ORGANIC OPTOELECTRIC DEVICE AND DISPLAY DEVICE
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Provided is a compound providing an organic optoelectric device having characteristics such as high efficiency and long life. The present invention relates to a compound represented by chemical formula 1, an organic optoelectric device including the same, and a display device including the organic optoelectric device. (Here, definitions of X^1 to X^8 are defined as same as the specification.)COPYRIGHT KIPO 2015
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Paragraph 0294; 0297; 0298; 0299
(2016/11/21)
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- Green synthesis of stable Cu(0) nanoparticles onto reduced graphene oxide nanosheets: A reusable catalyst for the synthesis of symmetrical biaryls from arylboronic acids under base-free conditions
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Highly stable Cu(0) nanoparticles were synthesized on reduced graphene oxide (rGO) sheets using a cost-effective and green method. The synthesized Cu(0)-nanoparticle-rGO composites exhibit excellent catalytic activity for the synthesis of symmetrical biaryls from arylboronic acids under microwave irradiation. The reaction proceeds smoothly in base-free conditions with easy recovery and reuse of the catalyst. The methodology is compatible with various functional groups and provides an attractive protocol for the synthesis of symmetrical biaryls with very good yields. HRTEM, XPS and XRD analyses showed the catalyst to be recyclable. The Cu(0) nanoparticles are stable in the rGO nanosheets, and the particle size distribution and oxidation state of the Cu(0) nanoparticle remain the same after performing the chemical reaction.
- Hussain, Najrul,Gogoi, Pranjal,Azhaganand, Vedi Kuyil,Shelke, Manjusha V.,Das, Manash R.
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p. 1251 - 1260
(2015/02/19)
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- Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
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A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
- Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
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p. 10498 - 10504
(2015/11/18)
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- Copper-catalyzed oxidative decarboxylative C-H arylation of benzoxazoles with 2-nitrobenzoic acids
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A copper-catalyzed oxidative decarboxylative coupling of benzoxazoles with 2-nitrobenzoic acids was developed. This methodology favors electron-rich benzoxazoles and electron-deficient benzoic acids and enables the preparation of a variety of arylated benzoxazoles in good yields. The trends in product yields suggest a delicate balance between the decarboxylation and C-H arylation steps.
- Chen, Lijun,Ju, Lin,Bustin, Katelyn A.,Hoover, Jessica M.
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supporting information
p. 15059 - 15062
(2015/10/12)
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- Zeolite-assisted nitration of biphenyl using nitric acid
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The nitration process using 95 % nitric acid instead of the classical nitric acid-sulfuric acid system appears to be attractive and promising in the preparation of nitro compounds. The ratio of 2-nitrobiphenyl (2a) isomer to 4-nitrobiphenyl (2b) can reach 0.69 in a good yield of 78.42 %. The isomeric distribution of the product mononitrobiphenyl was found to be superior to traditional methods. Raising the ratio of 95 % nitric acid and biphenyl to 4:1, the yield of dinitration products can reach more than 78.08 %, as a mixture of 2,2-dinitrobiphenyl (3a), 2,4-dinitrobiphenyl (3b), and 4,4-dinitrobiphenyl (3c).
- Tai, Yanfang,Peng, Xinhua,Shi, Chunjie,Dong, Xiongzi
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p. 867 - 872
(2015/03/03)
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- Magnesium complexes containing biphenyl-based tridentate imino-phenolate ligands for ring-opening polymerization of rac-lactide and α- methyltrimethylene carbonate
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A series of racemic 2-[(2′-(dimethylamino)biphenyl-2-ylimino)methyl]- 4-R2-6-R1-phenols (L1H-L4H) were reacted with {Mg[N(SiMe3)2]2}2 to provide four heteroleptic magnesium complexes (L1-4)MgN(SiMe 3)2·(THF)n (1, R1 = tBu, R2 = Me, n = 1; 2, R1 = R2 = CMe2Ph, n = 0; 3, R1 = CPh3, R2 = tBu, n = 1; 4, R1 = Br, R2 = tBu, n = 0), which have been fully characterized. X-ray structural determination shows that complex 1 possesses a monomeric structure, but complex 4 is dimeric with C2-symmetry 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. The heteroleptic complexes 1-4 efficiently initiate the ring-opening polymerization of rac-lactide and α-methyltrimethylene carbonate (α-MeTMC) and the polymerizations are better controlled in the presence of 2-propanol. In general, the introduction of a bulky ortho-substituent on the phenoxy unit results in increases of both the catalytic activity and the stereo- or regioselectivity of the corresponding magnesium complex. Microstructure analyses of the resulting PLAs revealed that Pr values range from 0.46 to 0.81, depending on the catalyst and the polymerization conditions. For racemic α-MeTMC, detailed analyses using 1H and 13C NMR spectroscopy indicated the preferential ring-opening of α-MeTMC at the most hindered oxygen-acyl bond (Xreg = 0.65-0.86).
- Yi, Wei,Ma, Haiyan
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p. 5200 - 5210
(2014/04/03)
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- N-picolinamides as ligands for Ullmann-type homocoupling reactions
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The use of N-phenylpicolinamide (NPPA) as a ligand in Ullmann-type homocoupling reactions of aryl iodides and bromides in common solvents, such as DMF and MeCN has been successfully demonstrated at room temperature. In addition, this work provided the first example of the homocoupling of an aryl chloride at 82 °C, which is a relatively low temperature when compared to regular Ullmann reaction temperatures. Also, NPPA was successfully employed in base-and heat free Suzuki reactions, including electron rich and poor aryl halides with heteroarylboronic acids in moderate yields.
- Damkaci, Fehmi,Altay, Esra,Waldron, Matthew,Knopp, Michael A.,Snow, David,Massaro, Nicholas
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supporting information
p. 690 - 693
(2014/01/23)
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- Single-step oxidative homocoupling of aryl Grignard reagents via Co(II), Ni(II) and Cu(II) Complexes under air
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A simple catalytic system of direct synthesis for the symmetrical biaryls using catalytic amounts of Co(II), Ni(II) and Cu(II) complexes has been developed. The reaction system involves in situ synthesis of Grignard reagents. The complexes, containing bidentate Schiff base and dmit (2-thioxo-1,3-dithiole- 4,5-dithiolate) ligands, were compatible with diverse functionalities and afford a high yield of biaryls in a single step, proving to be promising catalysts in homocoupling reactions. Atmospheric oxygen is used as an oxidant which renders a green, simple and economical catalytic route. Copyright
- Bhat, Aparna P. I.,Bhat, Badekai Ramachandra
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p. 383 - 388
(2014/06/09)
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- Dilithium tetrachlorocuprate(II) catalyzed oxidative homocoupling of functionalized grignard reagents
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An efficient procedure is described for the oxidative homocoupling of functionalized Grignard reagents using a catalytic amount of dilithium tetrachlorocuprate(II) (CuLi2Cl4) in the presence of pure oxygen gas. This method is applied successfully to a variety of aryl, heteroaryl, alkyl, alkenyl and alkynyl halides, which are converted into the corresponding homocoupled products in good to excellent yields. Georg Thieme Verlag Stuttgart · New York.
- Hua, Si-Kai,Hu, Qiu-Peng,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 518 - 526
(2013/03/29)
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- One-step synthesis of biaryls under mild conditions
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A one-step synthesis of symmetrical biaryls was developed and uses a nickel(III) complex containing a Schiff base and dithiolate ligands as a catalyst for the homocoupling of in situ generated Grignard reagents. The coupling reaction was performed at room temperature with molecular oxygen as the oxidant, which renders the reaction energy-efficient and environmentally friendly. The catalytic methodology is compatible with diverse functionalities, including chlorido, nitro, nitrile, and heteroatoms, and provides biaryls in appreciable yields. A practical, room-temperature nickel(III) catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents. The use of molecular oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionalities and affords biaryls in appreciable yields. Copyright
- Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
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p. 7139 - 7144
(2013/11/06)
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- Nickel catalyzed one pot synthesis of biaryls under air at room temperature
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A practical, room temperature catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents using a nickel(ii) complex. The use of atmospheric oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionality to afford biaryls in appreciable yields. The Royal Society of Chemistry 2013.
- Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
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p. 22191 - 22198
(2013/11/06)
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- METHOD FOR PRODUCING BIARYL COMPOUND
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A method for producing a biaryl compound represented by the formula (2) [in-line-formulae]Ar—Ar ??(2)[/in-line-formulae] wherein Ar represents an aromatic group which can have a substituent, comprising conducting a coupling reaction of a compound represented by the formula (1) [in-line-formulae]Ar—Cl ??(1)[/in-line-formulae] wherein Ar represents the same meaning as defined above, in the presence of copper metal and a copper salt.
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Page/Page column 9
(2012/05/21)
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- Homocoupling of aryl Grignard reagents to form biaryls using ruthenium(III) complex, [RuCl(C3S5)(H2O)(PPh 3)2]
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Ruthenium(III) complex, [RuCl(C3S5)(H 2O)(PPh3)2] is an effective catalyst for the homocoupling of the aryl-Grignard reagents (ArMgX) to form biaryl derivatives. The catalytic methodology involves an in situ generation of the Grignard reagents. The method is simpler, economical and of great synthetic utility. The reaction will be environmental friendly due to the involvement of molecular oxygen as oxidant.
- Aparna,Bhat, Badekai Ramachandra
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experimental part
p. 73 - 78
(2012/06/01)
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- A general Pd-catalyzed decarboxylative cross-coupling reaction between aryl carboxylic acids: Synthesis of biaryl compounds
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Acid to acid: A general method has been developed for the synthesis of biaryl compounds through a decarboxylative cross-coupling reaction between two different (hetero)aryl carboxylic acids (see scheme). The use of a Pd II/PCy3 catalyst enables the cross-coupling reaction of electronically different or electronically similar aryl carboxylic acids. This method is compatible with substrates having nitro, cyano, fluoro, chloro, bromo, trifluoromethyl, and methoxy substituents. Copyright
- Hu, Peng,Shang, Yaping,Su, Weiping
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supporting information; experimental part
p. 5945 - 5949
(2012/07/03)
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- Ferrous salt-promoted homocoupling of arenediazonium tetrafluoroborates under mild conditions
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A simple and efficient protocol has been developed for the synthesis of various symmetrical biaryls in good to excellent yields from the homocoupling reactions of arenediazonium salts with ferrous salt in carbon tetrachloride solution under mild reaction conditions. Moreover, the novel homocoupling has been demonstrated to proceed via an electron transfer reaction mechanism.
- Ding, Yiyuan,Song, Qingbao,Cheng, Kai,Qi, Chenze
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p. 6269 - 6272,4
(2012/12/11)
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- Fe(II)-catalysed homocoupling of arenediazonium tetrafluoroborates
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An efficient procedure for the synthesis of biaryls was catalysed by Fe(acac)2 and zinc powder in carbon tetrachloride solution at 60 °C using arenediazonium salts is reported. Symmetrical bi-aryl molecules with various substituents on the phenyl ring (methyl, trifluoromethyl, halogen, nitro, methoxyl) were synthesised in good yields in a short time under air. Zinc powder was used as reductant in the reaction to facilitate the regeneration of the iron(II) catalyst.
- Zhou, Jiatian,Yu, Shuangshuang,Cheng, Kai,Qi, Chenze
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p. 672 - 674
(2013/02/22)
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- Decarboxylative etherification of aromatic carboxylic acids
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Decarboxylative Chan-Evans-Lam-type couplings are presented as a new strategy for the regiospecific construction of diaryl and alkyl aryl ethers starting from easily available aromatic carboxylic acids. They allow converting various aromatic carboxylate salts into the corresponding aryl ethers by reaction with alkyl orthosilicates or aryl borates, under aerobic conditions in the presence of silver carbonate as the decarboxylation catalyst and copper acetate as the cross-coupling catalyst.
- Bhadra, Sukalyan,Dzik, Wojciech I.,Goossen, Lukas J.
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supporting information; scheme or table
p. 9938 - 9941
(2012/08/08)
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- Homocoupling of aryl halides in flow: Space integration of lithiation and FeCl3 promoted homocoupling
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The use of FeCl3 resulted in a fast homocoupling of aryllithiums, and this enabled its integration with the halogen-lithium exchange reaction of aryl halides in a flow microreactor. This system allows the homocoupling of two aryl halides bearing electrophilic functional groups, such as CN and NO2, in under a minute.
- Nagaki, Aiichiro,Uesugi, Yuki,Tomida, Yutaka,Yoshida, Jun-Ichi
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supporting information; experimental part
p. 1064 - 1069
(2011/10/04)
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- Efficient one-pot synthesis of dibenzopyranones via a decarboxylative cross-coupling and lactonization sequence
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A highly selective palladium bis(acetoacetonate)/copper(I) chloride [Pd(acac)2/CuCl] catalytic system for the preparation of dibenzopyranones has been developed. Tandem decarboxylative coupling and lactonization can be realized in one pot using commercially available starting materials. The reaction proceeded well for a range of different substrates. Copyright
- Luo, Jiaying,Lu, Youling,Liu, Saiwen,Liu, Jing,Deng, Guo-Jun
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supporting information; scheme or table
p. 2604 - 2608
(2011/12/01)
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- Synthesis of biaryls by Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids
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By carefully choosing the right substrate ratio, catalyst combination, and base, symmetrical and unsymmetrical biaryls can be readily synthesized through the Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids. The reaction gave the desired products in 40-90% yield and is compatible with 2-nitro-, 2-methoxy-, 2-fluoro-, and 2-chloro-substituted benzoic acids. With the correct substrate ratio, catalyst combination, and base, symmetrical and unsymmetrical biaryls can be readily synthesized through the Pd-catalyzed decarboxylative homo- and heterocoupling of substituted benzoic acids.
- Xie, Kai,Wang, Sizhuo,Yang, Zhiyong,Liu, Jidan,Wang, Anwei,Li, Xiujian,Tan, Ze,Guo, Can-Cheng,Deng, Wei
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supporting information; experimental part
p. 5787 - 5790
(2011/11/06)
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- Decarboxylative homocoupling of (hetero)aromatic carboxylic acids
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A variety of hetero(aromatic) carboxylic acids are shown to undergo decarboxylative homocoupling, mediated by a Pd/Ag system. This novel methodology for the synthesis of symmetrical biaryls avoids the use of haloarenes and organometallic compounds as starting materials.
- Cornella, Josep,Lahlali, Hicham,Larrosa, Igor
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supporting information; experimental part
p. 8276 - 8278
(2010/12/19)
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- Chiral biphenylamide derivative: An efficient organocatalyst for the enantioselective synthesis of α-hydroxy phosphonates
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The aldol reactions of α-keto phosphonates and aldehydes were facilitated by an axially chiral biphenylprolinamide under mild conditions, affording the synthetically and pharmaceutically useful products in high yields and excellent enantioselectivities.
- Jiang, Jun,Chen, Xiaohong,Wang, Jun,Hui, Yonghai,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
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supporting information; experimental part
p. 4355 - 4357
(2009/12/25)
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- Biaryl synthesis via Pd-catalyzed decarboxylative coupling of aromatic carboxylates with aryl halides
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A new strategy for the regiospecific construction of unsymmetrical biaryls is presented, in which easily available salts of carboxylic acids are decarboxylated in situ to give arylmetal species that serve as the nucleophilic component in a catalytic cross-coupling reaction with aryl halides. The catalyst system consists of a copper phenanthroline complex that mediates the extrusion of CO2 from aromatic carboxylates to generate arylcopper species, and a palladium complex that catalyzes the cross-coupling of these intermediates with aryl halides. This bimetallic system allows the direct coupling of various aryl, heteroaryl, or vinyl carboxylic acids with aryl or heteroaryl iodides, bromides, or chlorides at 160°C in the presence of a mild base such as potassium carbonate. The present scope and potential economic impact of the reaction are demonstrated by the synthesis of 42 biaryls, some of which are of substantial industrial relevance. Remaining challenges and future perspectives of the new transformation are discussed.
- Goossen, Lukas J.,Rodriguez, Nuria,Melzer, Bettina,Linder, Christophe,Deng, Guojun,Levy, Laura M.
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p. 4824 - 4833
(2008/01/27)
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- Manganese- or iron-catalyzed homocoupling of grignard reagents using atmospheric oxygen as an oxidant
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Atmospheric oxygen was used for the first time as an oxidant in metal-catalyzed homocoupling of Grignard reagents. These manganese- or iron-catalyzed reactions are efficient, cheap, and eco-friendly. They are applicable to the large-scale synthesis of symmetrical conjugated compounds. Copyright
- Cahiez, Gerard,Moyeux, Alban,Buendia, Julien,Duplais, Christophe
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p. 13788 - 13789
(2008/04/11)
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- Copper(I)-catalysed homo-coupling of aryldiazonium salts: synthesis of symmetrical biaryls
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Copper(I) triflate acts as an efficient stoichiometric reagent for the homo-coupling of aryldiazonium salts bearing electron-withdrawing group(s), to yield symmetrical biaryls in acetonitrile under mild reaction conditions. Aryldiazonium salts bearing electron-donating groups undergo the reaction by using catalytic amounts of a copper complex prepared in situ from copper(II) triflate and 2,2′-bipyridine with metallic copper as an ultimate reductant.
- Cepanec, Ivica,Litvi?, Mladen,Udikovi?, Josipa,Pogoreli?, Ivan,Lovri?, Marija
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p. 5614 - 5621
(2007/12/29)
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- Synthesis of 1,2,3,4-tetrahydrocarbazoles and related tricyclic indoles
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Reduction of 2-(2-nitrophenyl)-2-cyclohexene-1-ones using palladium on carbon under 1 atm of hydrogen gas at ambient temperature affords 1,2,3,4-tetrahydrocarbazoles in excellent isolated yields. The starting materials were prepared by intermolecular Stille coupling of 2-iodo-2-cyclohexen-1-ones with 2-(tributylstannyl)-1-nitrobenzenes.
- Scott, Tricia L.,Burke, Nicholas,Carrero-Martínez, Grissell,S?derberg, Bj?rn C.G.
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p. 1183 - 1190
(2007/10/03)
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- Synthesis of 2-nitro- and 2,2′-dinitrobiphenyls by means of the suzuki cross-coupling reaction
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Mechanistic investigations and protocols for the synthesis of 2-nitrobiphenyls and 2,2′-dinitrobiphenyls are disclosed. It is revealed that obstacles appear during the transmetalation step when the phenylboronic acid is substituted with a nitro group in the 2-position, whereas when substituted in the 3- or 4-positions, the reaction follows similar patterns as found in the electrophilic substitution of nitrobenzenes, an observation that may be attributed to the elimination step of the catalytic cycle.
- Gonzalez, Raquel Rodriguez,Liguori, Lucia,Carrillo, Alberto Martinez,Bjorsvik, Hans-Rene
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p. 9591 - 9594
(2007/10/03)
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- Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents
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(Chemical Equation Presented) Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents is described. The reaction is highly chemoselective (CN, COOEt and NO2 groups are tolerated). The procedure was used to perform intramolecular couplings. This cyclization reaction is the key step of the total synthesis of the N-methylcrinasiadine.
- Cahiez, Gerard,Chaboche, Christophe,Mahuteau-Betzer, Florence,Ahr, Mathieu
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p. 1943 - 1946
(2007/10/03)
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- Synthesis of quinolines, 2-quinolones, phenanthridines, and 6(5H)-phenanthridinones via palladium[0]-mediated Ullmann cross-coupling of 1-bromo-2-nitroarenes with β-halo-enals, -enones, or -esters
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Palladium[0]-mediated Ullmann cross-coupling of 1-bromo-2-nitrobenzene (1 R = H) and its derivatives with a range of β-halo-enals, -enones, or -esters readily affords the corresponding β-aryl derivatives, which are converted into the corresponding quinolines, 2-quinolones, phenanthridines, or 6(5H)-phenanthridinones on reaction with dihydrogen in the presence of Pd on C or with TiCl3 in aqueous acetone.
- Banwell, Martin G.,Lupton, David W.,Ma, Xinghua,Renner, Jens,Sydnes, Magne O.
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p. 2741 - 2744
(2007/10/03)
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- An efficient phosphine-free palladium coupling for the synthesis of new 2-arylbenzo[b]thiophenes
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Straightforward and rapid access to 2-arylbenzo[b]thiophenes has been developed. It involved a catalytic coupling of 3-activated benzo[b]thiophenes with several aryl halides in the presence of a phosphine-free palladium system. In case of fragile functional groups such as aldehydes, a quaternary ammonium was used as an additive as with the other substrates, the coupling performed better and faster in the presence of a crown ether, the best one being DCH-18-C-6, with good yields and low reaction times. This method would provide a direct access to novel structures of biological interest.
- Dit Chabert, Jérémie Fournier,Joucla, Lionel,David, Emilie,Lemaire, Marc
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p. 3221 - 3230
(2007/10/03)
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- Synthesis of indoles via palladium[0]-mediated ullmann cross-coupling of o-halonitroarenes with α-halo-enones or -enals
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(Matrix presented) Palladium[0]-mediated Ullmann cross-coupling of o-halonitrobenzene (1) and various related nitroarenes with a range of α-halo-enones (e.g., 2) or -enals readily affords the expected α-arylenones, e.g., 3, or -enals, which are converted into the corresponding indoles, e.g., 4, on reaction with dihydrogen in the presence of Pd on C.
- Banwell, Martin G.,Kelly, Brian D.,Kokas, Okanya J.,Lupton, David W.
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p. 2497 - 2500
(2007/10/03)
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- Total synthesis of (±)-rhazinal, an alkaloidal spindle toxin from Kopsia teoi
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The title alkaloid I and its B-nor-congener 3, both of which display potent and unusual anti-mitotic properties, have been synthesized in racemic form and characterised by single-crystal X-ray analysis.
- Banwell, Martin G.,Edwards, Alison J.,Jolliffe, Katrina A.,Smith, Jason A.,Hamel, Ernest,Verdier-Pinard, Pascal
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p. 296 - 305
(2007/10/03)
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- Synthesis of Secondary Arylamines through Copper-Mediated Intermolecular Aryl Amination
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(Equation presented) A mild intermolecular copper-mediated amination of aryl iodides has been developed. The reaction takes place at room temperature or heating at 90°C and tolerates halogens attached to the aromatic ring. Its synthetic applications include a synthetic protocol for unsymmetrical N,N′-dialkylated phenylenediamines and both a stepwise and a general synthetic method for N-aryl secondary amines via Ns-anilides (readily obtained by reaction of the Ns-amide).
- Okano, Kentaro,Tokuyama, Hidetoshi,Fukuyama, Tohru
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p. 4987 - 4990
(2007/10/03)
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- Palladium-catalyzed synthesis of 1,2-dihydro-4(3H)-carbazolones. Formal total synthesis of murrayaquinone A
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Two sequential palladium-catalyzed reactions are the key steps in a novel synthetic route to 1,2-dihydro-4(3H)-carbazolones. The steps are an intermolecular Stille cross-coupling followed by a reductive N-heteroannulation. A formal total synthesis of murrayaquinone A, employing this sequence, is reported.
- Scott, Tricia L.,S?derberg, Bj?rn C. G.
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p. 6323 - 6332
(2007/10/03)
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- Synthetic reactions using metal powders under microwave irradiation
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Liquid-phase synthetic reactions that require the use of metal powders are widely regarded as being unsuited to heating with microwave radiation, as they tend to exhibit destructive arcing. In a previous paper, we examined the factors that lead to arcing in these systems and, hence, how it may be controlled. This paper describes the application of those findings in a range of microwave-induced syntheses of organometallic and organic compounds, where metal powders are necessary. Although reaction yields were similar to those observed when conventional heating is used, the rapid nature of microwave heating leads to a slight reduction in reaction times.
- Whittaker,Mingos
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p. 3967 - 3970
(2007/10/03)
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- ARYL BORATES
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The invention provides a process for covalently coupling organic compounds which comprises reacting an aromatic ring compound having a halogen or halogen-like substituent at a coupling position with a diboron derivative in the presence of a Group VIII metal catalyst and a suitabIe base. The invention also provides useful arylboron intermediates.
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