- Nickel/β-CD-catalyzed Suzuki–Miyaura cross-coupling of aryl boronic acids with aryl halides in water
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In this study, a convenient nickel-catalyzed protocol has been introduced for the Suzuki–Miyaura coupling reaction. A simple mixture of Ni(II) and unfunctionalized β-cyclodextrin (β-CD) was used to cross-coupling of aryl halides with aryl boronic acids for the synthesis of biaryls in water. β-CD is a water-soluble seminatural cyclic oligosaccharide, environmentally friendly biomaterial, inexpensive, and commercially available ligand. This ligand with low solubility in usual organic solvents has been used for the synthesis of biaryls in good to excellent yields. The cross-coupling results in the presence of Ni(II)/β-CD catalytic system showed that the coupling reaction carried out with appropriate yields for both electron-rich and electron-deficient aryl halides. The coupling reaction completed in water as a green solvent. The catalyst was also recycled for four runs with a small decrease in its catalytic activity. The presented new method allows an easier and more cost-efficient synthesis of biaryls from the reaction of arylboronic acids with various aryl halides in water.
- Payamifar, Sara,Kazemi, Foad,Kaboudin, Babak
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- Synthesis of mixed silylene-carbene chelate ligands from nheterocyclic silylcarbenes mediated by nickel
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The NiII -mediated tautomerization of the N-heterocyclic hydrosilylcarbene L2Si(H)(CH2)NHC1, where L2 = CH(C=CH2)(CMe)(NAr)2, Ar = 2,6-iPr2C6H3 ; NHC = 3,4,5-trimethylimidazol-2-yliden-6-yl, leads to the first N-heterocyclic silylene (NHSi)-carbene (NHC) chelate ligand in the dibromo nickel(II) complex [L1SiD(CH2)(NHC)NiBr2]2 (L1 = CH(MeC=NAr)2). Reduction of 2 with KC8 in the presence of PMe3 as an auxiliary ligand afforded, depending on the reaction time, the N-heterocyclic silyl-NHC bromo NiII complex [L2Si(CH2)NHCNiBr(PMe3)] 3 and the unique Ni0 complex [h2(Si-H){L2Si(H)(CH2)NHC}Ni(PMe3)2] ,inf>4 featuring an agostic Si-H→!Ni bonding interaction. When 1,2-bis(dimethylphosphino)ethane (DMPE) was employed as an exogenous ligand, the first NHSi-NHC chelate-ligand-stabilized Ni0 complex [L1SiD(CH2)NHCNi(dmpe)] 5 could be isolated. Moreover, the dicarbonyl Ni0 complex 6, [L1SiD-(CH2)NHCNi(CO)2], is easily accessible by the reduction of 2 with K(BHEt3) under a CO atmosphere. The complexes were spectroscopically and structurally characterized. Furthermore, complex 2 can serve as an efficient precatalyst for Kumada-Corriu-type cross-coupling reactions.
- Tan, Gengwen,Enthaler, Stephan,Inoue, Shigeyoshi,Blom, Burgert,Driess, Matthias
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- Synthesis of 3-aryl thiophenes from disodium 2-aryl succinates: Role of red phosphorus
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Role played by red phosphorus in the synthesis of 3-aryl thiophenes from disodium 2-aryl succinates using P4S10 discussed. A new simple method for the synthesis of 2-(4-methylphenyl)succinic acid is also described.
- Marwah,Marwah,Shankar Rao,Trivedi
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- Ni ion-containing ionic liquid salt and Ni ion-containing immobilized ionic liquid on silica: Application to Suzuki cross-coupling reactions between chloroarenes and arylboronic acids
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Bis(1-n-butyl-3-methyl-imidazolium)tetrachloronickelate ([Bmim]2[NiCl4]), which is a nickel ion-containing ionic liquid, and immobilized nickel ion-containing ionic liquid (ImmNi2+_IL) on silica surface were prepared and applied as new catalysts for Suzuki cross-coupling reactions between aryl chlorides and arylboronic acids. It was found that pretreatment of the catalysts and the addition of triphenylphosphine to the reaction system greatly promoted the reactions. Before the addition of substrates, [Bmim]2[NiCl4] should be treated with K3PO4 in dioxane at a refluxing temperature for 1 h, and ImmNi2+_IL should be treated with NaOtBu in dioxane at room temperature for 30 min. An active precursor for the catalytic reactions was found to be a Ni carbene species formed by pretreatment with the bases as characterized by NMR and EXAFS. Reusability was confirmed for ImmNi2+_IL.
- Zhong, Chongmin,Sasaki, Takehiko,Tada, Mizuki,Iwasawa, Yasuhiro
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- Redox-Divergent Construction of (Dihydro)thiophenes with DMSO
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Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.
- Chen, Qing-An,He, Gu-Cheng,Hu, Yan-Cheng,Ji, Ding-Wei,Liu, Heng,Zhang, Xiang-Xin,Zhao, Chao-Yang
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supporting information
p. 24284 - 24291
(2021/10/08)
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- Pd-NHCs Enabled Suzuki-Miyaura Cross-Coupling of Arylhydrazines via C–N Bond Cleavage
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We describe a highly efficient protocol for cross-coupling of phenylhydrazines with arylboronic acids by Pd-NHCs under aerobic reaction condition. A series of well-defined Pd-NHCs complexes were evaluated and the relationship between the structure and the catalytic properties was investigated. It was disclosed that the Pd-PEPPSI-IPr proved to be the robust precatalyst, providing access to a range of (hetero)biaryls in good to excellent yields.
- Zeng, Xiao-Xiao,Li, Dong-Hui,Zhou, Zhen,Xu, Chang,Liu, Feng-Shou
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supporting information
(2021/03/01)
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- Modular and Selective Arylation of Aryl Germanes (C?GeEt3) over C?Bpin, C?SiR3 and Halogens Enabled by Light-Activated Gold Catalysis
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Selective C (Formula presented.) –C (Formula presented.) couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe3, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings.
- Dahiya, Amit,Fricke, Christoph,Funes-Ardoiz, Ignacio,Gevondian, Avetik G.,Schoenebeck, Franziska,Sherborne, Grant J.
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supporting information
p. 15543 - 15548
(2020/06/22)
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- para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
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Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
- Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
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p. 5058 - 5061
(2020/05/18)
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- Preparation method of para-substituted aryl compound
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The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
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- Schiff-based Pd(II)/Fe(III) bimetallic self-assembly monolayer—preparation, structure, catalytic dynamic and synergistic
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Graphene oxide supported Pd (II)/Fe (III) bimetallic catalytic monolayer (denoted as GO@H-Pd/Fe) was prepared and characterized. Its catalytic performances for Suzuki coupling reaction, synergetic effect and catalytic mechanism were systematic investigated. Results showed that orientation, composition and distribution of catalyst had efficient effect on catalytic activity. Catalytic activity of GO@H-Pd0.10/Fe0.90 was 475 times more than that of GO@H-Pd due to the ordered catalytic monolayer immobilized on GO, proper ratio of Pd/Fe and the synergetic effect between Pd(II) and Fe(III) which could form active cluster containing Pd and Fe. The Pd(II) could be made more negative by transferring electron from GO to Fe(III) via ligand and then to Pd, improving its catalytic activity since it was easy for oxide addition. It also exhibited better stability and recyclability at least 8 times due to proper functional ligand and support. Deactivation mechanism was confirmed to be the aggregation of active centre during the recycling. Heterogeneous catalytic mechanism was also proved by poison test, hot filtration and ReactIR. The results of ReactIR presented different dynamic catalytic process for GO@H-Pd0.10Fe0.90 and homogeneous catalyst (Li2PdCl4/FeCl3·6H2O).The activation energies were 9.7 KJ/mol and 3.7 KJ/mol obtained for heterogeneous and homogeneous catalyst, respectively. Considering the diffusion effect, the factor of supports on the activity was also investigated by ReactIR, with which that GO@H-Pd0.10Fe0.90 catalytic activity was higher than that of homogeneous catalyst could be confirmed.
- Huang, Pingping,Song, Erran,Sun, Yimeng,Li, Tiesheng,Wei, Donghui,Liu, Minghua,Wu, Yangjie
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- Stannylation of Aryl Halides, Stille Cross-Coupling, and One-Pot, Two-Step Stannylation/Stille Cross-Coupling Reactions under Solvent-Free Conditions
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Solvent-free protocols for palladium-catalyzed stannylation of aryl halides, Stille cross-coupling, and one-pot, two-step stannylation/Stille cross-coupling (SSC) are reported for the first time. (Het)aryl halides bearing acceptor, donor, as well as sterically demanding substituents are stannylated and/or coupled in high yields. The reactions are catalyzed by conventional palladium(II) acetate/PCy3 [Pd(OAc)2/PCy3] under air, using available base CsF, and without the use of high purity reagents. The developed synthetic procedures are versatile, robust, and easily scalable. The absence of solvent, and the elimination of isolation procedures of aryl stannanes makes the SSC protocol simple, step economical, and highly efficient for the synthesis of biaryls in a one-pot two-step procedure.
- Gribanov, Pavel S.,Golenko, Yulia D.,Topchiy, Maxim A.,Minaeva, Lidiya I.,Asachenko, Andrey F.,Nechaev, Mikhail S.
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p. 120 - 125
(2018/01/17)
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- Synthesis of heteroaryl compounds through cross-coupling reaction of aryl bromides or benzyl halides with thienyl and pyridyl aluminum reagents
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An efficient method for synthesis of useful biaryl building blocks containing 2-thienyl, 3-thienyl, 2-pyridyl, and 3-pyridyl moieties was provided through cross-coupling reactions of aryl bromides or benzyl halides with heteroaryl aluminum reagents in the presence of Pd(OAc)2 and (o-tolyl)3P. The coupling reaction also worked efficiently with heteroaryl bromides affording series of heterobiaryl compounds. The reaction of phenylbromide with in situ prepared 3-pyridyl aluminum was demonstrated to afford the product 8a in high yield. Additionally, the catalytic system was also suited well for the coupling reaction of benzyl halides with pyridyl aluminum reagents to afford series of pyridyl-arylmethane.
- Chen, Xu,Zhou, Lingmin,Li, Yimei,Xie, Tao,Zhou, Shuangliu
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p. 230 - 239
(2014/01/17)
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- Suzuki-miyaura cross-coupling under solvent-free conditions
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A solvent-free reaction protocol for Suzuki-Miyaura cross-couplings was developed. (Hetero)aryl bromides and chlorides are coupled with pinacol arylboronates in high yields. The reaction is catalyzed by conventional bis(triphenylphosphine)palladium(II) chloride [(PPh3) 2PdCl2] and/or palladium(II) acetate/SPhos [Pd(OAc) 2/SPhos] under air. Copyright
- Asachenko, Andrey F.,Sorochkina, Kristina R.,Dzhevakov, Pavel B.,Topchiy, Maxim A.,Nechaev, Mikhail S.
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p. 3553 - 3557
(2014/01/06)
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- Benzenesulfonyl chlorides: New reagents for access to alternative regioisomers in palladium-catalysed direct arylations of thiophenes
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The palladium-catalysed coupling of benzenesulfonyl chlorides with thiophene derivatives allows regioselective access to β-arylated thiophenes. The reaction proceeds with easily accessible catalyst, base and substrates, without oxidant or ligand and tolerates a variety of substituents on both the benzene and thiophene moieties.
- Yuan, Kedong,Doucet, Henri
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p. 392 - 396
(2014/01/06)
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- A simple catalytic system based on PdCl2(CH3CN) 2 in water for cross-coupling reactions using diazonium salts
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Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts.
- El Bakouri, Ouissam,Fernández, Martí,Brun, Sandra,Pla-Quintana, Anna,Roglans, Anna
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p. 9761 - 9765
(2013/10/22)
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- Expanded ring diaminocarbene palladium complexes: Synthesis, structure, and Suzuki-Miyaura cross-coupling of heteroaryl chlorides in water
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A series of new 6- and 7-membered N-heterocyclic carbene (NHC) complexes of palladium (NHC)Pd(cinn)Cl (cinn = cinnamyl = 3-phenylallyl) were synthesized and characterized structurally in the solid state. The influence of ring size (5, 6 or 7) and bulkiness of N-aryl substituents (Mes = 2,4,6-trimethylphenyl, or Dipp = 2,6-diisopropylphenyl) in carbenes on palladium catalysed Suzuki-Miyaura cross-coupling was revealed. Due to the unique stereoelectronic properties of expanded ring NHCs, a versatile, highly efficient green protocol of coupling of heteroaromatic chlorides and bromides with boronic acids has been developed. High quantitative yields of biaryls were achieved with water as solvent, under air, using low catalyst and phase transfer agent loadings, and with mild and environmentally benign base NaHCO3. The Royal Society of Chemistry 2013.
- Kolychev, Eugene L.,Asachenko, Andrey F.,Dzhevakov, Pavel B.,Bush, Alexander A.,Shuntikov, Viacheslav V.,Khrustalev, Victor N.,Nechaev, Mikhail S.
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p. 6859 - 6866
(2013/08/25)
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- Nickel-catalyzed Suzuki-Miyaura coupling of heteroaryl ethers with arylboronic acids
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Nickel-catalyzed Suzuki-Miyaura coupling of heteroaryl ethers with arylboronic acids was described. Selective activation of the phenol C-O bonds was achieved by converting them into the corresponding aryl 2,4-dimethoxy-1,3,5- triazine-6-yl ethers, in which aryl C-O bond could be selectively cleaved with inexpensive, air-stable NiCl2(dppf) as a catalyst. Coupling of these readily accessible heteroaryl ethers proved tolerant of extensive functional groups.
- Li, Xiao-Jian,Zhang, Jin-Ling,Geng, Yu,Jin, Zhong
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p. 5078 - 5084
(2013/06/27)
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- Catalytic C-H arylation of unactivated heteroaromatics with aryl halides by cobalt porphyrin
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Direct C-H arylation of unactivated heteroaromatics with aryl halides catalyzed by cobalt porphyrin is reported. The reaction is proposed to go through a homolytic aromatic substitution reaction. The aryl radical is electrophilic and a SOMO-HOMO interaction is predominant in the aryl radical addition process.
- Qian, Ying Ying,Wong, Ka Lai,Zhang, Meng Wen,Kwok, Tsz Yiu,To, Ching Tat,Chan, Kin Shing
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supporting information; experimental part
p. 1571 - 1575
(2012/04/11)
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- General and highly efficient fluorinated-N-heterocyclic carbene-based catalysts for the palladium-catalyzed Suzuki-Miyaura reaction
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A general and highly efficient trifluoromethylated-N-heterocyclic carbene (NHC)-based catalyst for the palladium-catalyzed Suzuki-Miyaura reaction was reported. In the presence of the catalyst, reactions of non-activated aryl chlorides and triflates with aryl boronic acids occurred at room temperature with good to excellent yields (63-98%). In addition, catalysts generated from a combination of Pd(OAc)2/imidazolium salt 6a is not only effective for the coupling of heteroaryl boronic acid with aryl halides and heteroaryl halides, but also efficient for coupling of other heteroaryl halides and heteroaryl boronic acids. Finally, the catalyst is highly effective for Suzuki-Miyaura reaction of aryl bromides and chlorides with 0.01-0.1 mol % loading if the temperature was raised at refluxed THF/H2O.
- Liu, Taoping,Zhao, Xiaoming,Shen, Qilong,Lu, Long
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supporting information; experimental part
p. 6535 - 6547
(2012/08/28)
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- Nickel-catalysed cross-coupling reaction of aryl(trialkyl)silanes with aryl chlorides and tosylates
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Using highly stable, readily accessible, and recyclable 2-(2-hydroxyprop-2-yl)cyclohexyl-substituted arylsilanes activated by a mild carbonate base, nickel-catalysed silicon-based aryl-aryl cross-coupling reaction proceeds for the first time with inexpensive aryl chlorides and tosylates in a highly chemoselective manner.
- Tang, Shi,Takeda, Masahide,Nakao, Yoshiaki,Hiyama, Tamejiro
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supporting information; experimental part
p. 307 - 309
(2011/02/24)
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- Highly active and recyclable silica gel-supported palladium catalyst for mild cross-coupling reactions of unactivated heteroaryl chlorides
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Silica gel-supported β-ketoiminatophosphane-Pd complex (Pd@SiO 2) was shown to be a highly active and long-lived catalyst for aqueous Suzuki, Stille and Sonogashira coupling reactions of heteroaryl chlorides. A wide range of heteroaryl chlorides could be efficiently coupled with different nucleophilic partners in the presence of only 0.5 mol% catalyst and under mild conditions. This is one of the most powerful heterogeneous catalysts for the couplings of diverse heteroaryl chlorides. Furthermore, the catalyst could be reused with almost consistent activity. The Royal Society of Chemistry 2010.
- Lee, Dong-Hwan,Jung, Ji-Young,Jin, Myung-Jong
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experimental part
p. 2024 - 2029
(2011/02/22)
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- CATALYST COMPOSITION AND PROCESS FOR PRODUCING CROSS-COUPLED COMPOUND USING SAME
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A catalyst composition for a cross-coupling reaction comprising a nickel metal source, a fluorine source, and a nitrogen-containing heterocyclic compound having a specific structure, or a phosphine compound. Using this catalyst composition, a cross-coupled compound R5—R6 (wherein R5 and R6 are an aryl or heteroaryl group, or a linear, branched or cyclic alkyl group or a linear, branched or cyclic alkenyl group) is produced with a high selectivity by allowing an organometallic compound of the formula (2) R5-MY1 or the formula (3) R5-M-R5 (wherein R5 is the same as defined above, M is a Mg or Zn atom, and Y1 is a halogen atom) to react with a compound of the formula (4) R6—Y2 (wherein R6 is the same as defined above, and Y2 is a halogen atom, a methanesulfonate group, a toluenesulfonate group or a trifluoromethanesulfonate group).
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Page/Page column 9-10
(2010/08/07)
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- Synthesis of cis - and trans-diisothiocyanato-bis(NHC) complexes of nickel(II) and applications in the Kumada-Corriu reaction
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Metathetical reaction of AgSCN with a series of trans-dihalido-bis(carbene) nickel(II) complexes in CH3CN readily afforded the novel diisothiocyanato-bis(carbene) complexes [Ni(NCS)2(NHC)2] (trans-2a, NHC = 1,3-diisopropylbenzimidazolin-2-ylidene; trans-2b, NHC = 1,3-diisobutylbenzimidazolin-2-ylidene; trans-2c, NHC = 1,3- dibenzylbenzimidazolin-2-ylidene; cis-2d, NHC = 1,3-di(2-propenyl) benzimidazolin-2-ylidene; cis-2e, NHC = 1-propyl-3-methylbenzimidazolin-2- ylidene) as greenish-yellow powders in moderate to good yields. While dihalido-bis(carbene) Ni(II) complexes exclusively form trans-complexes, a trans-cis isomerization occurs upon halido-isothiocyanato exchange with complexes bearing less bulky carbene ligands, i.e., cis-2d/e. DFT calculations indicated that this isomerization can be attributed to a reduced energy difference between trans- and cis-isomers of diisothiocyanato complexes. All complexes have been characterized by multinuclear NMR spectroscopy, ESI mass spectrometry, and X-ray diffraction analysis. A catalytic study revealed that cis-complexes generally exhibit greater activities in the Kumada-Corriu coupling reaction.
- Jothibasu, Ramasamy,Huang, Kuo-Wei,Huynh, Han Vinh
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experimental part
p. 3746 - 3752
(2010/12/20)
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- Expanded heterogeneous Suzuki-Miyaura coupling reactions of aryl and heteroaryl chlorides under mild conditions
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A mesoporous LTA zeolite (MP-LTA)-supported palladium catalyst was developed for the highly efficient Suzuki-Miyaura reaction of aryl and heteroaryl chlorides. The couplings of various aryl chlorides with arylboronic acids in aqueous ethanol were efficiently achieved in the presence of 1.0 mol% of the catalyst. Furthermore, the scope of this catalyst was extended to the coupling of heteroaryl chlorides. Regardless of the substituents, all of the coupling reactions were very clean and highly efficient under mild heating. It shows that our catalyst is one of the most powerful heterogeneous catalysts for the coupling of a wide range of aryl and heteroaryl chlorides. The catalyst could be repetitively used at least 10 times without a significant loss of its catalytic activity. Compared to mesoporous SBA-15 and MCM-41 materials, the MP-LTA support proved to be very stable and robust to prevent degradation upon reuse.
- Lee, Dong-Hwan,Choi, Minkee,Yu, Byung-Woo,Ryoo, Ryong,Taher, Abu,Hossain, Shahin,Jin, Myung-Jong
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supporting information; experimental part
p. 2912 - 2920
(2010/04/01)
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- Formation of homoleptic tetracarbene versus m-Chelating dicarbene complexes of nickel(ii) and applications in kumada-Corriu couplings
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The formation of mono- versus bis(chelate) Ni11 complexes bearing N-heterocyclic dicarbene ligands can be controlled by the flexibility of the ligand bridge. A short methylene spacer exclusively gives rise to a dicationic bis(chelate) complex [Ni(MeCCmeth)2]Br2 (1), whereas a more flexible propylene spacer affords a neutral monochelate complex [NiBr2(MeCCprop)] (2). Complex 2 was found to autoionize very slowly to the corresponding dicationic bis(chelate) over ca. 45 d in [D6]dmso. The formation of the bis-versus mono-chelate complex can be attributed to the different stabilities of the resulting metallacycles. The catalytic activity of mono-chelate 2 was tested in the Kumada-Corriu coupling of aryl halides with arylmagnesium reagents at ambient temperature. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.
- Huynh, Han Vinh,Jothibasu, Ramasamy
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experimental part
p. 1926 - 1931
(2009/10/30)
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- Highly selective biaryl cross-coupling reactions between aryl halides and aryl Grignard reagents: A new catalyst combination of N-heterocyclic carbenes and iron, cobalt, and nickel fluorides
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Combinations of N-heterocyclic carbenes (NHCs) and fluoride salts of the iron-group metals (Fe, Co, and Ni) have been shown to be excellent catalysts for the cross-coupling reactions of aryl Grignard reagents (Ar1MgBr) with aryl and heteroaryl halides (Ar2X) to give unsymmetrical biaryls (Ar1-Ar2). Iron fluorides in combination with SIPr, a saturated NHC ligand, catalyze the biaryl cross-coupling between various aryl chlorides and aryl Grignard reagents in high yield and high selectivity. On the other hand, cobalt and nickel fluorides in combination with IPr, an unsaturated NHC ligand, exhibit interesting complementary reactivity in the coupling of aryl bromides or iodides; in contrast, with these substrates the iron catalysts show a lower selectivity. The formation of homocoupling byproducts is suppressed markedly to less than 5% in most cases by choosing the appropriate metal fluoride/NHC combination. The present catalyst combinations offer several synthetic advantages over existing methods: practical synthesis of a broad range of unsymmetrical biaryls without the use of palladium catalysts and phosphine ligands. On the basis of stoichiometric control experiments and theoretical studies, the origin of the unique catalytic effect of the fluoride counterion can be ascribed to the formation of a higher-valent heteroleptic metalate [Ar1MF2]MgBr as the key intermediate in our proposed catalytic cycle. First, stoichiometric control experiments revealed the stark differences in chemical reactivity between the metal fluorides and metal chlorides. Second, DFT calculations indicate that the initial reduction of di- or trivalent metal fluoride in the wake of transmetalation with PhMgCl is energetically unfavorable and that formation of a divalent heteroleptic metalate complex, [PhMF2]MgCl (M ) Fe, Co, Ni), is dominant in the metal fluoride system. The heteroleptic ate-complex serves as a key reactive intermediate, which undergoes oxidative addition with PhCl and releases the biaryl cross-coupling product Ph-Ph with reasonable energy barriers. The present crosscoupling reaction catalyzed by iron-group metal fluorides and an NHC ligand provides a highly selective and practical method for the synthesis of unsymmetrical biaryls as well as the opportunity to gain new mechanistic insights into the metal-catalyzed cross-coupling reactions.
- Hatakeyama, Takuji,Hashimoto, Sigma,Ishizuka, Kentaro,Nakamura, Masaharu
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supporting information; experimental part
p. 11949 - 11963
(2009/12/08)
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- Biaryl and aryl ketone synthesis via Pd-catalyzed decarboxylase coupling of carboxylate salts with aryl triflates
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A bimetallic catalyst system has been developed that for the first time allows the decarboxylative crosscoupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic crosscoupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of CuI/1,10- phenanthroline (10-15 mol %) and PdI2/phosphine (23 mol%) in NMP for 1-24 h, the other involving CuI/l,10-phenanthroline (615mol%) and PdBr2/Tol-BINAP (2 mol % ) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylase crosscouplings are discussed.
- Goossen, Lukas J.,Linder, Christophe,Rodriguez, Nuria,Lange, Paul P.
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supporting information; experimental part
p. 9336 - 9349
(2010/04/03)
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- Highly efficient suzuki-miyaura coupling of heterocyclic substrates through rational reaction design
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A dicyclohexyl(2-sulfo-9-(3-(4-sulfophenyl)propyl)-9H-fluoren-9-yl) phosphonium salt was synthesized in 64% overall yield in three steps from simple commercially available starting materials. The highly water-soluble catalyst obtained from the corresponding phosphine and [Na2PdCl4] enabled the Suzuki coupling of a broad variety of N- and S-heterocyclic substrates. Chloropyridines (-quinolines) and aryl chlorides were coupled with aryl-, pyridineor indoleboronic acids in quantitative yields in water/n-butanol solvent mixtures in the presence of 0.005-0.05 mol% of Pd catalyst at 100°C, chloropurines were quantitatively Suzuki coupled in the presence of 0.5 mol% of catalyst, and S-heterocyclic aryl chlorides and aryl- or 3-pyridylboronic acids required 0.01-0.05 mol % Pd catalyst for full conversion. The key to the high activity of the Pd-phosphine catalyst is the rational design of the reaction parameters (i.e., the presence of water in the reaction mixture, good solubility of reactants and catalyst in n-butanol/water (3:1), and the electron-rich and sterically demanding nature of the phosphine ligand).
- Fleckenstein, Christoph A.,Plenio, Herbert
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scheme or table
p. 4267 - 4279
(2009/05/07)
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- Decarboxylative biaryl synthesis from aromatic carboxylates and aryl triflates
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A new catalyst system, generated in situ from Cu2O, 1,10-phenanthroline, PdI2, and Tol-BINAP, for the first time allows the decarboxylative coupling of carboxylic acids with aryl triflates. In contrast to previous decarboxylative couplings that remained limited to certain activated carboxylates, e.g., ortho-substituted benzoates, this halide-free protocol is generally applicable to aromatic carboxylic acid salts regardless of their substitution pattern. Copyright
- Goossen, Lukas J.,Rodriguez, Nuria,Linder, Christophe
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supporting information; experimental part
p. 15248 - 15249
(2009/03/11)
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- Efficient Suzuki-Miyaura coupling of (hetero)aryl chlorides with thiophene- and furanboronic acids in aqueous n-butanol
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(Chemical Equation Presented) An efficient Suzuki cross-coupling protocol enables the reaction of N-hetero and normal aryl chlorides with thiophene- and furanboronic acids. Coupling is effected in aqueous n-butanol as the solvent in near quantitative yield with a catalyst loading of 0.1-1 mol %. For heterocyclic substrates aqueous catalysis is found to be more efficient than Suzuki coupling under anhydrous conditions. The developed Suzuki coupling procedure utilizes biodegradable solvents and is useful for large scale reactions, as it includes the facile product separation from a biphasic solvent mixture without the need for additional organic solvents during workup.
- Fleckenstein, Christoph A.,Plenio, Herbert
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p. 3236 - 3244
(2008/09/20)
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- Microwave-promoted Suzuki coupling reactions with organotrifluoroborates in water using ultra-low catalyst loadings
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The Suzuki reaction in water using parts per million concentrations of palladium is reported using potassium trifluoroborates as alternatives to boronic acids as substrates.
- Arvela, Riina K.,Leadbeater, Nicholas E.,Mack, Tamera L.,Kormos, Chad M.
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p. 217 - 220
(2007/10/03)
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- Polymer-Supported Synthesis of Regioregular Head-to-Tail-Coupled Oligo(3-arylthiophene)s Utilizing a Traceless Silyl Linker
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The solid-phase synthesis of regioregular head-to-tail-coupled oligo(3-arylthiophene)s has been achieved in high yield and purity by using a traceless silyl ether linkage. In the first step, the solution-phase synthesis of this class of conjugated oligomers was investigated. Benzyl alcohol was chosen to serve as a mimic for the anchoring group of the hydroxymethyl-substituted polystyrene matrix. The development of a novel regioselective iodination process for silyl-protected thiophenes faciliates the successful application of the solution-phase protocol to the solid phase. Satisfactory loading was obtained by reaction of chlorosilyl-functionalized 3-arylthiophene with hydroxymethyl polystyrene in the presence of imidazole. The suitability of the following iterative halogenation and Suzuki cross-coupling sequence is illustrated by the preparation of a quater(3-arylthiophene), the first regioregular head-to-tail-coupled oligothiophene that is synthesized on solid support. Removal of the conjugated oligomers from the solid support could be effectively achieved by treatment with tetrabutylammonium fluoride.
- Briehn, Christoph A.,Kirschbaum, Thomas,Baeuerle, Peter
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p. 352 - 359
(2007/10/03)
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- Direct Preparation of 3-Thienyl Organometallic Reagents: 3-Thienylzinc and 3-Thienylmagnesium Iodides and 3-Thienylmanganese Bromides and Their Coupling Reactions
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3-Thienylzinc and 3-thienylmagnesium iodides can be generated from the direct oxidative addition of Rieke zinc and magnesium to 3-iodothiophene, respectively. The direct preparation of 3-thienylmanganese bromides from the reaction of Rieke manganese with 3-bromothiophene and 3,4-dibromothiophene is also performed. These 3-thienyl organometallic reagents have been found to be regiostable intermediates and undergo coupling reactions with a variety of versatile electrophiles such as acid chlorides, aryl iodides, aldehydes, and disulfide.
- Rieke, Reuben D.,Kim, Seung-Hoi,Wu, Xiaoming
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p. 6921 - 6927
(2007/10/03)
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- Synthesis of unsymmetrical 2,3-diaryl- and 2,4-diarylthiophenes starting from 2,5-dichlorothiophene
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Unsymmetrically substituted 2,4-diaryl- and 2,3-diarylthiophenes were synthesized from 2,5-dichlorothiophene via 4-aryl-2-chlorothiophenes in two and four steps including Ni-mediated cross-coupling, respectively. Aluminum chloride-catalyzed reaction of 3-aryl-2-chlorothiophenes with some aromatic ethers unexpectedly led to the formation of the corresponding 2,4-isomers.
- Sone,Sato,Umetsu,Yoshino,Takahashi
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p. 2187 - 2194
(2007/10/02)
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- Attempted Simmons-Smith reaction on α-oxoketene dithioacetals: A new general route to 3,4-substituted and annelated thiopenes
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A new general synthesis of 3- and 3,4-substituted 4a-q, 3,4-annelated 7a-d and condensed tricyclic 9a-e thiophenes has been developed through Simmons-Smith reaction of the respective α-oxoketene dithioacetals. Extension of the reaction of α-cinnamoylketene dithioacetals 10a-e and its higher enyl analogs 13a-d, 15a-c gave the corresponding 3-styryl 11a-e and 3-di- and trienyl 14a-d, 16a-c thiophenes in highly regioselective manner. A probable mechanism involving an unusual intramolecular aldol condensation of sulphonium ylid formed through carbenoid methylene insertion on divalent sulfur has been suggested.
- Bhat,Thomas,Ila,Junjappa
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p. 10377 - 10388
(2007/10/02)
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- AN IMPROVED SYNTHESIS OF 3-ARYL THIOPHENES USING PHASE-TRANSFER CO-CATALYSTS
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An efficient and facile synthesis of 3-aryl thiophenes from disodium 2-aryl succinates using phosphorus penta sulphide-red phosphorus under phase transfer co-catalyst is reported in near quantative yield.
- Marwah, Padma,Marwah, A.K.,Rao, G. Shankar
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p. 2809 - 2816
(2007/10/02)
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- A New and Simple Route to 3-Arylthiophenes
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3-Arylthiophenes were prepared from 2,5-dichlorothiophene in two steps. 2,5-Dichlorothiophene reacted regioselective with various aromatic compounds in the presence of AlCl3 under mild conditions to give 4-aryl-2-chlorothiophenes.The latter compounds were easily converted to the corresponding 3-arylthiophenes by catalytic dechloronation in good yields.
- Sone, Tyo,Inoue, Manabu,Sato, Kazuaki
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p. 3779 - 3781
(2007/10/02)
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- A High Yielding Synthesis of 3-Arylthiophenes Under Phase-Tranfer Conditions
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A convenient, high-yield method for the large-scale preparation of 3-arylthiophenes by phase-transfer catalyzed (PTC) cyclization of disodium 2-arylsuccinates in o-dichlorobenzene using a mixture of diphosphorus pentasulfide and red phosphorous is described.
- Sastry, C. V. Reddy,Marwah, A. K.,Marwah, Padma,Rao, G. Shankar,Shridhar, D. R.
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p. 1024 - 1025
(2007/10/02)
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