- General and efficient methodology for the Suzuki-Miyaura reaction in technical grade 2-propanol
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The reaction profile of a series of palladium-based catalysts was examined in the Suzuki-Miyaura reaction using technical grade 2-propanol as solvent and potassium t-butoxide as base. The results generally show high activity. The method allows for the coupling of electron-rich aryl chlorides with sterically hindered aryl boronic acids to produce tri-ortho-substituted biaryls in high yields using very mild conditions and short reaction times.
- Navarro, Oscar,Oonishi, Yosihiro,Kelly, Roy A.,Stevens, Edwin D.,Briel, Oliver,Nolan, Steven P.
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Read Online
- Biphenylene-substituted ruthenocenylphosphine for Suzuki-Miyaura coupling of sterically hindered aryl bromides
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(Chemical Equation Presented) A highly general, active, and stable catalytic system was realized in the palladium-catalyzed Suzuki-Miyaura reactions of sterically hindered aryl bromides with arylboronic acids using biphenylene-substituted di-tert-butylrut
- Hoshi, Takashi,Saitoh, Ippei,Nakazawa, Taichi,Suzuki, Toshio,Sakai, Jun-Ichi,Hagiwara, Hisahiro
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Read Online
- Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, aC36H12 open geodesic polyarene
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Circumtrindene (6, C, one of the largest open geodesic polyarenes ever reported, exhibits fullerene-like reactivity at its interior carbon atoms, whereas its edge carbons react like those of planar polycyclic aromatic hydrocarbons (PAHs). The Bingel-Hirsc
- Cho, Hee Yeon,Ansems, Ronald B. M.,Scott, Lawrence T.
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Read Online
- Halogen-Bridged Methylnaphthyl Palladium Dimers as Versatile Catalyst Precursors in Coupling Reactions
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Halogen-bridged methylnaphthyl (MeNAP) palladium dimers are presented as multipurpose Pd-precursors, ideally suited for catalytic method development and preparative organic synthesis. By simply mixing with phosphine or carbene ligands, they are in situ converted into well-defined monoligated complexes. Their catalytic performance was benchmarked against state-of-the-art systems in challenging Buchwald–Hartwig, Heck, Suzuki and Negishi couplings, and ketone arylations. Their use enabled record-setting activities, beyond those achievable by optimization of the ligand alone. The MeNAP catalysts permit syntheses of tetra-ortho-substituted arenes and bulky anilines in near-quantitative yields at room temperature, allow mono-arylations of small ketones, and enable so far elusive cross-couplings of secondary alkyl boronic acids with aryl chlorides.
- Doppiu, Angelino,Goo?en, Lukas J.,Hu, Zhiyong,Pirkl, Nico,Sivendran, Nardana
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supporting information
p. 25151 - 25160
(2021/10/19)
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- Palladium(II) Complexes of a Neutral CCC-Tris(N-heterocyclic carbene) Pincer Ligand: Synthesis and Catalytic Applications
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Treatment of tris-azolium precursor 1 with palladium acetate under thermal conditions provided a CCC-pincer palladium(II) complex (2) bearing three NHCs (one imidazolylidene and two triazolylidenes) and one iodide ligand. Further treatment of complex 2 with an excess of AgSbF6 generates tris(carbene) dicationic palladium complex 3 in which the iodine ligands are exchanged with SbF6 anions and the metal center is stabilized by one acetonitrile ligand. Complexes 2 and 3 were tested in several cross coupling reactions showing high conversions under low catalyst loadings and mild reaction conditions. Additionally, complexes 2 and 3 performed well in the hydrosilylation of terminal alkynes with good selectivity toward the E-isomer.
- Angeles-Beltrán, Deyanira,Mendoza-Espinosa, Daniel,Rendón-Nava, David,Rheingold, Arnold L.
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supporting information
p. 2166 - 2177
(2021/07/20)
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- Non-c2-symmetric bis-benzimidazolium salt applied in the synthesis of sterically hindered biaryls
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A novel non-C2-symmetric bis-benzimidazolium salt derived from (±)-valinol has been prepared by a simple and straightforward process in good yield. The structure of bis-benzimidazolium salt provided a bulky steric group on the ethylene bridge; which facilitates the catalytic efficacy in the C(sp2 )–C(sp2 ) formation. Its catalytic activity in Suzuki–Miyaura cross-coupling reaction of unactivated aryl chlorides has been found to have high efficacy in 1 mol% Pd loading. This protocol demonstrated the potential on the synthesis of sterically hindered biaryls.
- Chen, Yen-Hsin,Hsu, Tung-Yu,Huang, Shu-Jyun,Hung, Pei-Yu,Lee, Dong-Sheng,Lu, Ta-Jung,Wei, Ting-Rong
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- A substituted tricyclohexylphosphane with “conformational lock”
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A substituted tricyclohexylphosphane with “conformational lock”, tri(4-trans-(tert-butyl)cyclohexyl)phosphane L, has been designed and synthesized. The ligand has shown similar steric bulkiness and conformations to tricyclohexylphosphane at solid state. The comparable or slightly better performance of ligand L compared to PCy3 in Suzuki-Miyaura coupling has demonstrated the similar steric properties of two ligands in reaction and the effectiveness of the chair conformer of the cyclohexyl rings. The ineffectiveness of both L and PCy3 in palladium-catalyzed aminations has also manifested the weakness of such ligands and a sterically more bulky ligand is needed in order to develop a more efficient amination.
- Li, Tiejun,Liu, Ziyue,Tang, Wenjun,Zhao, Jianhong
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- Hydroxyl-functionalized triazolylidene-based PEPPSI complexes: Metallacycle formation effect on the Suzuki coupling reaction
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We report the preparation and full characterization of a series of hydroxyl functionalized 1,2,3-triazolylidene-based PEPPSI complexes 2a-c and their catalytic application in the Suzuki cross coupling reaction of aryl chlorides/amides with boronic acids. Under basic reaction conditions, complexes 2a-c show a notable increase in their catalytic efficiency compared with two ether-wingtip functionalized PEPPSI analogues (3 and 4) and a commercially available NHC-Pd complex (5). The catalytic results suggest that deprotonation of the hydroxyl group in complexes 2a-c plays an important role in the overall process. Deprotonation of the alcohol moiety of complexes 2a-b with sodium tert-butoxide allows for the isolation of metallacycles 6a-b, which are proposed as the active species of cross coupling reactions.
- Rendón-Nava, David,álvarez-Hernández, Alejandro,Rheingold, Arnold L.,Suárez-Castillo, Oscar R.,Mendoza-Espinosa, Daniel
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supporting information
p. 3214 - 3222
(2019/03/13)
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- Catalyst shuttling enabled by a thermoresponsive polymeric ligand: Facilitating efficient cross-couplings with continuously recyclable ppm levels of palladium
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A polymeric monophosphine ligand WePhos has been synthesized and complexed with palladium(ii) acetate [Pd(OAc)2] to generate a thermoresponsive pre-catalyst that can shuttle between water and organic phases, with the change being regulated by temperature. The structure of the polymeric ligand was confirmed with matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry and size-exclusion chromatography (SEC) analysis, as well as nuclear magnetic resonance (NMR) measurements. This polymeric metal complex enables highly efficient Pd-catalyzed cross-couplings and tandem reactions using 50 to 500 ppm palladium, and this can facilitate reactions that are tolerant to a broad spectrum of (hetero)aryl substrates and functional groups, as demonstrated with 73 examples with up to 99% isolated yields. Notably, 97% Pd remained in the aqueous phase after 10 runs of catalyst recycling experiments, as determined via inductively coupled plasma-atomic emission spectrometry (ICP-AES) measurements, indicating highly efficient catalyst transfer. Furthermore, a continuous catalyst recycling approach has been successfully developed based on flow chemistry in combination with the catalyst shuttling behavior, allowing Suzuki-Miyaura couplings to be conducted at gram-scales with as little as 10 ppm Pd loading. Given the significance of transition-metal catalyzed cross-coupling and increasing interest in sustainable chemistry, this work is an important step towards the development of a responsive catalyst, in addition to having high activity, by tuning the structures of the ligands using polymer science.
- Wang, Erfei,Chen, Mao
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p. 8331 - 8337
(2019/09/30)
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- METHOD FOR PRODUCING AROMATIC COMPOUND
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In a cross coupling reaction, in a case where a halogen atom is selected as the leaving group of the raw material compound, a harmful halogen waste forms as a by-product after the reaction, and disposal of the waste liquid is complicated and environmental burden is high. In a carbon-hydrogen activation cross coupling reaction which requires no halogen atom as the leaving group, although no halogen waste forms as a by-product, the reaction substrate is considerably restricted, and the reaction remains a limited molecular construction method. A method for producing an aromatic compound, which comprises subjecting an aromatic nitro compound and a boronic acid compound to a cross coupling reaction in the presence of a metal catalyst.
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Paragraph 0038; 0039; 0040; 0140; 0141; 0142; 0152
(2018/05/16)
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- Synthesis of a class of binaphthyl monophosphine ligands with a naphthofuran skeleton and their applications in Suzuki-Miyaura coupling reactions
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A series of new monophosphine ligands containing a naphthofuran skeleton have been prepared, characterized and evaluated in palladium-catalyzed Suzuki-Miyaura coupling reactions. Using Pd2(dba)3-L6 as the catalyst the reactions were performed with high catalytic activity under mild reaction conditions and the desired coupling products were obtained in good to excellent yields. The new catalyst system also showed broad substrate adaptability and practicality for gram-scale production.
- Zhou, Zihong,Liang, Hao,Xia, Wang,Chen, Huixuan,Zhang, Yaqi,He, Xuefeng,Yu, Sifan,Cao, Rihui,Qiu, Liqin
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p. 5967 - 5971
(2018/04/23)
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- SYNTHESIS OF PHOSPHINE LIGANDS BEARING TUNABLE LINKAGE: METHODS OF THEIR USE IN CATALYSIS
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A series of novel linked indolyl phosphine ligands for transition metals, the synthesis thereof and their use in catalytic coupling reactions are provided. The ligands provide improvements of trasition-metal-catalyzed reactions, including the range of substrates scope, reaction conditions and efficieny.
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Page/Page column 16; 18
(2017/12/02)
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- The Suzuki-Miyaura Coupling of Nitroarenes
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Synthesis of biaryls via the Suzuki-Miyaura coupling (SMC) reaction using nitroarenes as an electrophilic coupling partners is described. Mechanistic studies have revealed that the catalytic cycle of this reaction is initiated by the cleavage of the aryl-nitro (Ar-NO2) bond by palladium, which represents an unprecedented elemental reaction.
- Yadav, M. Ramu,Nagaoka, Masahiro,Kashihara, Myuto,Zhong, Rong-Lin,Miyazaki, Takanori,Sakaki, Shigeyoshi,Nakao, Yoshiaki
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supporting information
p. 9423 - 9426
(2017/07/24)
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- Mechanistic study of an improved Ni precatalyst for Suzuki-Miyaura reactions of aryl sulfamates: Understanding the role of Ni(I) species
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Nickel precatalysts are potentially a more sustainable alternative to traditional palladium precatalysts for the Suzuki-Miyaura coupling reaction. Currently, there is significant interest in Suzuki-Miyaura coupling reactions involving readily accessible phenolic derivatives such as aryl sulfamates, as the sulfamate moiety can act as a directing group for the prefunctionalization of the aromatic backbone of the electrophile prior to cross-coupling. By evaluating complexes in the Ni(0), (I), and (II) oxidation states we report a precatalyst, (dppf)Ni(σ-tolyl)(Cl) (dppf = 1,1'-bis(diphenylphosphino)-ferrocene), for Suzuki-Miyaura coupling reactions involving aryl sulfamates and boronic acids, which operates at a significantly lower catalyst loading and at milder reaction conditions than other reported systems. In some cases it can even function at room temperature. Mechanistic studies on precatalyst activation and the speciation of nickel during catalysis reveal that Ni(I) species are formed in the catalytic reaction via two different pathways: (i) the precatalyst (dppf)Ni(σ-tolyl)(Cl) undergoes comproportionation with the active Ni(0) species; and (ii) the catalytic intermediate (dppf)Ni(Ar) (sulfamate) (Ar = aryl) undergoes comproportionation with the active Ni(0) species. In both cases the formation of Ni(I) is detrimental to catalysis, which is proposed to proceed via a Ni(0)/Ni(II) cycle. DFT calculations are used to support experimental observations and provide insight about the elementary steps involved in reactions directly on the catalytic cycle, as well as off-cycle processes. Our mechanistic investigation provides guidelines for designing even more active nickel catalysts.
- Beromi, Megan Mohadjer,Nova, Ainara,Balcells, David,Brasacchio, Ann M.,Brudvig, Gary W.,Guard, Louise M.,Hazari, Nilay,Vinyard, David J.
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supporting information
p. 922 - 936
(2017/05/16)
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- TRI-(ADAMANTYL)PHOSPHINES AND APPLICATIONS THEREOF
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In one aspect, phosphine compounds comprising three adamantyl moieties (PAd3) and associated synthetic routes are described herein. Each adamantyl moiety may be the same or different. For example, each adamantyl moiety (Ad) attached to the phosphorus atom can be independently selected from the group consisting of adamantane, diamantane, triamantane and derivatives thereof. Transition metal complexes comprising PAd3 ligands are also provided for catalytic synthesis including catalytic cross-coupling reactions.
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Page/Page column 22
(2017/05/17)
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- Resorcinarene-Based o-Biarylphosphines in Palladium-Catalysed Suzuki–Miyaura Cross-Coupling Reactions of Bulky Substrates
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Two o-biarylphosphines, in which the arene ring remote from the phosphorus atom is part of a resorcin[4]arene cavitand, have been synthesised, characterised by X-ray diffraction and assessed in the cross-coupling reactions of bulky aryl chlorides with sterically hindered arylboronic acids. Only atropisomers with externally located P atoms were obtained. The resorcinarene ligand with the o-PCy2C6H4substituent was found to be more efficient than the Buchwald analogue SPhos in catalysing coupling reactions, reacting around 1.4 times faster. Its superior performance has been attributed to the permanent exo positioning of the metal centre, which engenders steric interactions with two pentyl substituents and therefore facilitates the reductive elimination step.
- Elaieb, Fethi,Sémeril, David,Matt, Dominique
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supporting information
p. 685 - 693
(2017/02/05)
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- NOVEL PRECATALYST SCAFFOLDS FOR CROSS-COUPLING REACTIONS, AND METHODS OF MAKING AND USING SAME
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The present invention provides novel transition-metal precatalysts that are useful in preparing active coupling catalysts. In certain embodiments, the precatalysts of the invention are air-stable and moisture-stable. The present invention further provides methods of making and using the precatalysts of the invention.
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Page/Page column 20
(2016/05/02)
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- An efficient indenyl-derived phosphine ligand for the Suzuki-Miyaura coupling of sterically hindered aryl halides
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An air-stable aryl substituted indenyl phosphine used in combination with Pd(OAc)2 provides a highly efficient catalyst for the Suzuki-Miyaura cross-coupling reaction of sterically hindered aryl halides with aryl boronic acids.
- Liu, Yan,Peng, Hui,Yuan, Jia,Yan, Meng-Qi,Luo, Xue,Wu, Qing-Guo,Liu, Sheng-Hua,Chen, Jian,Yu, Guang-Ao
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supporting information
p. 4664 - 4668
(2016/06/09)
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- Tri(1-adamantyl)phosphine: Expanding the Boundary of Electron-Releasing Character Available to Organophosphorus Compounds
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We report here the remarkable properties of PAd3, a crystalline air-stable solid accessible through a scalable SN1 reaction. Spectroscopic data reveal that PAd3, benefiting from the polarizability inherent to large hydrocarbyl groups, exhibits unexpected electron releasing character that exceeds other alkylphosphines and falls within a range dominated by N-heterocyclic carbenes. Dramatic effects in catalysis are also enabled by PAd3 during Suzuki-Miyaura cross-coupling of chloro(hetero)arenes (40 examples) at low Pd loading, including the late-stage functionalization of commercial drugs. Exceptional space-time yields are demonstrated for the syntheses of industrial precursors to valsartan and boscalid from chloroarenes with ~2 × 104 turnovers in 10 min.
- Chen, Liye,Ren, Peng,Carrow, Brad P.
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supporting information
p. 6392 - 6395
(2016/06/09)
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- Naphthofuran-structure-containing biaryl monophosphine ligands, and preparation method and application thereof
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The invention discloses naphthofuran-structure-containing biaryl monophosphine ligands, and a preparation method and application thereof. The biaryl monophosphine ligands are compounds disclosed the chemical structural formula (VIII) or antipodes or racemates thereof. According to the biaryl monophosphine ligands, the furan ring is introduced and forms a conjugated structure with the dinaphthalene, thereby increasing the steric hindrance of the phosphine ligands (including antipodes or racemates thereof) and the cloud density of the aromatic ring, and enhancing the stability of the complexes. The steric hindrance of the ligands is regulated, so that the ligands have novel structure. The preparation process comprises the steps of Sonogashira reaction, intramolecular cyclization, C-P coupling reaction and the like. The synthesis method is simple; and the obtained ligands have the advantages of high activity, favorable selectivity and the like when being used for Suzuki-Miyuara reaction.
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Paragraph 0081; 0082; 0083; 0089
(2017/01/02)
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- The Influence of Imidazolylidene Ligands with Bulky Resorcinarenyl Substituents on Catalysts for Suzuki-Miyaura Coupling
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PEPPSI-type imidazolylidene palladium complexes having their carbenic ring N-substituted with an aryl ring and a cavity-shaped unit [25,26,27,28-tetrapropyloxycalix[4]aren-5-yl or 6(10),12(16),18(22)-tetramethylenedioxy-2,8,14,20-tetrapentylresorcin[4]aren-5-yl (TPR)] have been prepared and assessed in Suzuki-Miyaura cross-couplings. Remarkable efficiency in the coupling of aryl chlorides with sterically hindered arylboronic acids was observed for the carbene ligand having its N atoms (N1, N2) substituted by a mesityl and a TPR group, respectively. This good performance possibly arises from strong steric interactions between the pentyl-substituted cavitand unit and the catalytic centre, which favours reductive elimination. Two of the imidazolium salts used for complex synthesis were characterised by X-ray diffraction analysis.
- Kalo?lu, Murat,Sémeril, David,Brenner, Eric,Matt, Dominique,?zdemir, Ismail,Toupet, Lo?c
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p. 1115 - 1120
(2016/03/15)
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- Arylcalixarenyl Phosphines in Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions
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Two electron-rich arylcalixarenylphosphines have been synthesized in three steps from the appropriate 5-bromocalix[4]arene precursor 1. The combination of 5-(2-diisopropylphosphinophenyl)-25,26,27,28-tetrapropyloxycalix[4]arene (5) and 5-(2-dicyclohexylphosphinophenyl)-25,26,27,28-tetrapropyloxycalix[4]arene (6), respectively, with [Pd2(dba)3] (dba = dibenzylideneacetone) generated effective catalysts for the cross-coupling reactions of hindered aryl chlorides and arylboronic acids. Dicyclohexylphosphino-substituted ligand 6 had a higher activity that that of 5, and the structures of ligand 5 and [AuCl·5] were determined by single-crystal X-ray diffraction studies. The solid-state structure of [AuCl·5] revealed that the gold atom lies above the outer face of the calixarene unit, with distances of 3.08 and 3.28 ? between the gold atom and the two closest aromatic carbon atoms of the calixarene moiety.
- Elaieb, Fethi,Hedhli, Ahmed,Sémeril, David,Matt, Dominique
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supporting information
p. 1867 - 1873
(2016/05/09)
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- Design of a versatile and improved precatalyst scaffold for palladium-catalyzed cross-coupling: (η3-1-tBu-indenyl)2(μ-Cl)2Pd2
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We describe the development of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2, a versatile precatalyst scaffold for Pd-catalyzed cross-coupling. Our new system is more active than commercially available (η3-cinnamyl)2(μ-Cl)2Pd2 and is compatible with a range of NHC and phosphine ligands. Precatalysts of the type (η3-1-tBu-indenyl)Pd(Cl)(L) can either be isolated through the reaction of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 with the appropriate ligand or generated in situ, which offers advantages for ligand screening. We show that the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold generates highly active systems for a number of challenging cross-coupling reactions. The reason for the improved catalytic activity of systems generated from the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold compared to (η3-cinnamyl)2(μ-Cl)2Pd2 is that inactive PdI dimers are not formed during catalysis.
- Melvin, Patrick R.,Nova, Ainara,Balcells, David,Dai, Wei,Hazari, Nilay,Hruszkewycz, Damian P.,Shah, Hemali P.,Tudge, Matthew T.
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p. 3680 - 3688
(2015/06/16)
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- Copper-catalyzed cross-coupling of boronic esters with aryl iodides and application to the carboboration of alkynes and allenes
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Copper-catalyzed Suzuki-Miyaura-type cross-coupling and carboboration processes are reported. The cross-couplings function well with a variety of substituted aryl iodides and aryl boronic esters and allows for orthogonal reactivity compared to palladium-catalyzed processes. The carboboration method includes both alkynes and allenes and provides access to highly substituted and stereodefined vinyl boronic esters. The alkyne carboboration method is highlighted in the simple one-pot synthesis of Tamoxifen. Cross-Cu-pling: The title cross-couplings function well with a variety of substituted aryl iodides and aryl boronic esters and allows for reactivity orthogonal to that of the palladium-catalyzed processes. The title carboboration method includes both alkynes and allenes and provides access to highly substituted and stereodefined vinyl boronic esters. The alkyne carboboration method is highlighted in a simple one-pot synthesis of Tamoxifen.
- Zhou, Yiqing,You, Wei,Smith, Kevin B.,Brown, M. Kevin
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supporting information
p. 3475 - 3479
(2014/04/03)
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- Insight into the efficiency of cinnamyl-supported precatalysts for the suzuki-miyaura reaction: Observation of Pd(I) dimers with bridging allyl ligands during catalysis
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Despite widespread use of complexes of the type Pd(L)(η3- allyl)Cl as precatalysts for cross-coupling, the chemistry of related Pd I dimers of the form (μ-allyl)(μ-Cl)Pd2(L) 2 has been underexplored. Here, the relationship between the monomeric and the dimeric compounds is investigated using both experiment and theory. We report an efficient synthesis of the PdI dimers (μ-allyl)(μ-Cl)Pd2(IPr)2 (allyl = allyl, crotyl, cinnamyl; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) through activation of Pd(IPr)( η3-allyl)Cl type monomers under mildly basic reaction conditions. The catalytic performance of the PdII monomers and their PdI μ-allyl dimer congeners for the Suzuki-Miyaura reaction is compared. We propose that the (μ-allyl)(μ-Cl) Pd2(IPr)2-type dimers are activated for catalysis through disproportionation to Pd(IPr)( η3-allyl)Cl and monoligated IPr-Pd0. The microscopic reverse comproportionation reaction of monomers of the type Pd(IPr)( η3-allyl)Cl with IPr-Pd0 to form PdI dimers is also studied. It is demonstrated that this is a facile process, and PdI dimers are directly observed during catalysis in reactions using PdII precatalysts. In these catalytic reactions, PdI μ-allyl dimer formation is a deleterious process which removes the IPr-Pd0 active species from the reaction mixture. However, increased sterics at the 1-position of the allyl ligand in the Pd(IPr)( η3-crotyl)Cl and Pd(IPr)( η3-cinnamyl)Cl precatalysts results in a larger kinetic barrier to comproportionation, which allows more of the active IPr-Pd0 catalyst to enter the catalytic cycle when these substituted precatalysts are used. Furthermore, we have developed reaction conditions for the Suzuki-Miyaura reaction using Pd(IPr)( η3-cinnamyl)Cl which are compatible with mild bases.
- Hruszkewycz, Damian P.,Balcells, David,Guard, Louise M.,Hazari, Nilay,Tilset, Mats
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supporting information
p. 7300 - 7316
(2014/06/09)
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- Suzuki-Miyaura cross-coupling reaction catalyzed by PEPPSI-type 1,4-di(2,6-diisopropylphenyl)-1,2,3-triazol-5-ylidene (tzIPr) palladium complex
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A 1,4-di(2,6-diisopropylphenyl)-1,2,3-triazol-5-ylidene (tzIPr)-based PEPPSI-type palladium complex was developed as an excellent precatalyst for the Suzuki-Miyaura cross-coupling reaction. The complex showed high activity under mild conditions for the cross-coupling reactions between various types of aryl chlorides and aryl boronic acids regardless of the steric and electronic nature of the substrates.
- Huang, Jie,Hong, Jong-Tai,Hong, Soon Hyeok
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p. 6630 - 6635
(2013/01/15)
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- Synthetic, structural, and catalytic studies of well-defined allyl 1,2,3-triazol-5-ylidene (tzNHC) palladium complexes
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A series of allyl 1,2,3-triazol-5-ylidene (tzNHC) palladium complexes was prepared, and the structures of the complexes were fully characterized by NMR and X-ray diffraction analyses. The donor properties of these ligands were evaluated by studying the vibrational spectra of their carbonyliridium complexes and their X-ray photoelectron spectra. These evaluations showed that the structures of the tzNHC palladium complexes are almost identical to those of the corresponding imidazole carbene palladium complexes, and that the tzNHC ligands have stronger donor properties than the imidazole carbene ligands. The relationship between catalytic activity and structure was examined by carrying out a room-temperature Suzuki-Miyaura coupling reaction, and the cinnamylpalladium complex bearing 1,4-bis(2,6-diisopropylphenyl)-3-methyl-1,2,3- triazol-5-ylidene (TPr) was found to be the most active catalyst. (cinnamyl)(TPr)PdCl showed high activity in the room-temperature reaction performed with aryl chlorides regardless of the electronic and steric properties of the substituents, and was effective in reactions with sterically crowded arylboronic acids. A series of (η3-allyl)palladium complexes bearing 1,2,3-triazole carbene (tzNHC) ligands has been prepared and characterized. The donor properties of tzNHC ligands are stronger than those of imidazole carbene ligands. The [1,4-bis(2,6-diisopropylphenyl)-3-methyl-1,2,3- triazol-5-ylidene](cinnamyl)PdCl complex shows high activity in the room-temperature Suzuki-Miyaura coupling reaction with aryl chlorides.
- Terashima, Takahiro,Inomata, Sayuri,Ogata, Kenichi,Fukuzawa, Shin-Ichi
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experimental part
p. 1387 - 1393
(2012/05/31)
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- METHOD FOR PRODUCING UNSATURATED ORGANIC COMPOUND
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A method for producing an unsaturated organic compound represented by the formula (3): [in-line-formulae](Y1)m-1—R1—R2—(Y2)n-1??(3)[/in-line-formulae] wherein Y1 represents R2 or X1, and Y2 represents R1 or B(X2)2, which comprises reacting a compound represented by the formula (1): [in-line-formulae]R1(X1)m??(1)[/in-line-formulae] wherein R1 represents an aromatic group or the like, X1 represents a leaving group and m represents 1 or 2, with a compound represented by the formula (2): [in-line-formulae]R2{B(X2)2}n??(2)[/in-line-formulae] wherein R2 represents an aromatic group or the like, X2 represents a hydroxyl group or the like, and n represents 1 or 2, in the presence of(a) a nickel compound selected from a nickel carboxylate, nickel nitrate and a nickel halide,(b) a phosphine compound such as 1,4-bis(dicyclohexylphosphino) butane,(c) an amine selected from a primary amine and a diamine such as N,N,N′,N′-tetramethyl-1,2-ethanediamine, and(d) an inorganic base.
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Page/Page column 10
(2011/04/14)
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- Highly efficient carbazolyl-derived phosphine ligands: Application to sterically hindered biaryl couplings
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A new family of phosphine ligands bearing a bulky carbazolyl scaffold is described. With the combination of ligand 2a and Pd(OAc)2, difficult tri-ortho-substituted biaryl couplings are accomplished smoothly. In particular, the catalyst loading as low as 0.02 mol% of Pd for non-activated 2,6-disubstituted aryl chloride coupling can be achieved.
- Chun To, Sheung,Yee Kwong, Fuk
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supporting information; experimental part
p. 5079 - 5081
(2011/06/10)
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- N-heterocyclic carbene/Pd(II)/1-methylimidazole complex catalyzed suzuki-miyaura coupling reaction of aryl chlorides in water
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A well-defined N-heterocyclic carbene (NHC)/palladium chloride/imidazole complex exhibited high catalytic activity in the Suzuki-Miyaura coupling reactions of aryl or heteroaryl chlorides performed in water. Under optimal conditions, all reactions gave the desired coupling products in good to high yields. Georg Thieme Verlag Stuttgart New York.
- Zhou, Xia-Xia,Shao, Li-Xiong
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experimental part
p. 3138 - 3142
(2011/10/31)
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- NHC-Pd(II)-Im (NHC = N-heterocyclic carbene; Im = 1-methylimidazole) complexes as efficient catalysts for Suzuki-Miyaura coupling reactions of aryl chlorides
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A new type of well-defined N-heterocyclic carbene (NHC)-palladium chloride-imidazole complexes derived from IPr HCl or IMes HCl, PdCl2 and 1-methylimidazole exhibits high catalytic activity in the room-temperature Suzuki-Miyaura coupling reactions of aryl or heteroaryl chlorides. Moreover, the large-scale (20.0 mmol) couplings in the presence of 0.01 mol% catalyst loading can also give the corresponding coupling products in high yields.
- Tang, Yi-Qiang,Lu, Jian-Mei,Shao, Li-Xiong
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experimental part
p. 3741 - 3744
(2011/12/02)
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- Room-temperature synthesis of tetra-ortho-substituted biaryls by NHC-catalyzed Suzuki-Miyaura couplings
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Into the groove: The introduction of a C2-symmetric N-heterocyclic carbene ligand with appropriately substituted naphthyl side chains enables the efficient Suzuki-Miyaura coupling to form bulky tetra-ortho-substituted biaryls from aryl bromides and chlorides at room temperature. DFT calculations uncover the subtle steric phenomena at play that lead to the superior catalytic performance. Cyoct=cyclooctyl. Copyright
- Wu, Linglin,Drinkel, Emma,Gaggia, Fiona,Capolicchio, Samanta,Linden, Anthony,Falivene, Laura,Cavallo, Luigi,Dorta, Reto
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supporting information; experimental part
p. 12886 - 12890
(2011/12/15)
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- Efficient synthesis of biaryls through the kumada reaction catalyzed by carbene adducts of cyclopalladated ferrocenylimine
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A series of carbene adducts of cyclopalladated ferrocenylimine were prepared, and evaluated in the cross-coupling reaction of aryl halides with Grignard reagents (the Kumada reaction). Complex d exhibited high catalytic activity for the coupling of aryl chlorides with sterically hindered Grignard reagents and the reaction tolerated various functional groups. A wide range of biaryls were efficiently obtained in good to excellent yields in the presence of 0.5 mol-% catalyst under mild reaction conditions.
- Ren, Gerui,Cui, Xiuling,Wu, Yangjie
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experimental part
p. 2372 - 2378
(2010/07/04)
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- New cyclopalladated benzothiophenes: A catalyst precursor for the Suzuki coupling of deactivated aryl chlorides
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Dimeric benzothiophene-based palladacycles were synthesized from thioanisole-substituted perfluoroalkyl propargyl imines and palladium(ii) salts via an intramolecular thiopalladation pathway. The treatment of benzothiophene-based palladacycles with an exc
- Subhas, Madavu Salian,Racharlawar, Shailesh S.,Sridhar,Kennady, P. Kavin,Likhar, Pravin R.,Kantam, Mannepalli Lakshmi,Bhargava, Suresh K.
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experimental part
p. 3001 - 3006
(2010/09/06)
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- Sulfonated N-heterocyclic carbenes for Pd-catalyzed sonogashira and suzuki-miyaura coupling in aqueous solvents
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The reactions of the N, N-diarylimidazolium and N, N-diarylimidazolinium salts with chlorosulfonic acid result in the formation of the respective disulfonated N-heterocyclic carbene (NHC) precursors in reasonable yields (46-77%). Water-soluble palladium catalyst complexes, in situ obtained from the respective sulfonated imidazolinium salt, sodium tetrachloropalladate (Na 2PdCl4) and potassium hydroxide (KOH) in water, were successfully applied in the copper-free Sonogashira coupling reaction in isopropyl alcohol/water mixtures using 0.2 mol% catalyst loading. The preformed (disulfonatedNHC)PdCl(cinnamyl) complex was used in aqueous Suzuki-Miyaura reactions at 0.1 mol% catalyst loading. The coupling protocol reported here is very useful for Sonogashira reactions of N- and 5-heterocyclic aryl bromides and chlorides with aryl- and alkylacetylenes.
- Roy, Sutapa,Plenio, Herbert
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experimental part
p. 1014 - 1022
(2010/06/17)
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- Ferrocenyl phosphine-oxazaphospholidine oxide ligands for the Suzuki-Miyaura coupling of hindered aryl bromides and chlorides
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A series of ferrocenyl oxazaphospholidine phosphines that differ electronically and sterically were investigated as ligands for the Suzuki-Miyaura cross-coupling reactions. One of these compounds, 1, was shown to be highly effective in the coupling reactions of bulky aryl bromides with boronic acids when combined with Pd(OAc)2, while another, 2, was capable of coupling aryl chlorides with boronic acids. However, these ligands were less effective in asymmetric induction.
- Vinci, Daniele,Martins, Nelson,Saidi, Ourida,Bacsa, John,Brigas, Amadeu,Xiao, Jianliang
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experimental part
p. 171 - 175
(2009/10/24)
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- Room-temperature Suzuki-Miyaura couplings in water facilitated by nonionic amphiphiles
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(Chemical Equation Presented) Use of a dilute aqueous solution containing a nonionic amphiphile allows efficient Suzuki-Miyaura cross-couplings of arylboronic acids with a wide array of aryl halides and pseudohalides, including sterically hindered and lipophilic substrates, in most cases at room temperature.
- Lipshutz, Bruce H.,Petersen, Tue B.,Abela, Alexander R.
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supporting information; experimental part
p. 1333 - 1336
(2009/04/12)
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- N-HETEROCYCLIC CARBENE METALLACYCLE CATALYSTS AND METHODS
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The present invention generally relates to materials and methods for catalytic reactions, including transition metal-catalyzed cross-coupling reactions. The materials may be stable metal complexes that do not require special handling or processing conditions. In some cases, materials of the invention advantageously may be synthesize in one synthetic step without the need for isolation of intermediate compounds. Also, materials of the invention may be synthesized from inexpensive and readily available starting materials, under relatively mild reaction conditions that do not require the exclusion of air, water, and the like. In some embodiments, the material is a N-heterocyclic carbene metallacycle complex. Such materials and methods may be useful in the production of fine chemicals, advanced materials and specialty polymers.
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Page/Page column 28; Sheet 18
(2009/01/23)
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- New cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions
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The invention is directed to a phosphine compound represented by general formula (1) wherein R' and R" independently are selected from alkyl, cycloalkyl and 2-furyl radicals, or R' and R" are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle; the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals; Cps is a partially substituted or completely substituted cyclopentadien-1-yl group, including substitutions resulting in a fused ring system, and wherein a substitution at the 1-position of the cyclopentadien-1-yl group is mandatory when the cyclopentadien-1-yl group is not part of a fused ring system or is part of an indenyl group. Also claimed is the use of these phosphines as ligands in catalytic reactions and the preparation of these phosphines.
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Page/Page column 53; 59
(2008/06/13)
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- Streamlined synthesis of the bippyphos family of ligands and cross-coupling applications
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We describe the efficient preparation of Bippyphos, 1. The key precursor to Bippyphos, 5, was prepared via a one-pot bromination of diketone 2 followed by alkylation with pyrazole and condensation with phenylhydrazine. Lithiation of 5 and trapping with ditert-butylchlorophosphine afforded Bippyphos, 1. Using this approach we have prepared several derivatives of Bippyphos to probe the structure and activity relationships of this family of phosphine ligands. We also demonstrate the utility of these ligands in Pdcatalyzed amination reactions and other cross-coupling reactions.
- Withbroe, Gregory J.,Singer, Robert A.,Sieser, Janice E.
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p. 480 - 489
(2013/01/03)
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- Transition metal complexes of N-heterocyclic carbenes, method of preparation and use in transition metal catalyzed organic transformations
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The present invention relates to catalysts of transition metal complexes of N-heterocyclic carbenes, their methods of preparation and their use in chemical synthesis. The synthesis, ease-of-use, and activity of the compounds of the present invention are substantial improvements over in situ catalyst generation. Further, the transition metal complexes of N-heterocyclic carbenes of the present invention may be used as precatalysts in metal-catalyzed cross-coupling reactions.
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Page/Page column 11; 16
(2010/11/26)
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- 9-Fluorenylphosphines for the Pd-catalyzed Sonogashira, Suzuki, and Buchwald-Hartwig coupling reactions in organic solvents and water
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The lithiation/alkylation of fluorene leads to various 9-alkyl-fluorenes (alkyl = Me. Et, /Pr, -Pr. -C18H25) in > 95% yields, for which lithiation and reaction with R2PCl (R = Cy, iPr, tBu) generates 9-alkyl, 9-PR2fluorenes which constitute electron-rich and bulky phosphine ligands. The in-situ-formed palladium-phosphinc complexes ([Na2PdCl4], phosphonium salt, base, substrates) were tested in the Sonogashira. Suzuki, and Buchwald-Hartwig reactions of aryl chlorides and aryl bromides in organic solvents. The Sonogashira coupling of aryl chlorides at 100-120°C leads to >90% yields with 1 mol % of Pd catalyst. The Suzuki coupling of aryl chlorides typically requires 0.05 mol % of Pd catalyst at 100°C in dioxane for quantitative product formation. To carry out "green" cross-coupling reactions in water, 9-ethylfluorenyldicyclohexylphosphine was reacted in sulphuric acid to generate the respective 2-sulfonated phosphonium salt. The Suzuki coupling of activated aryl chlorides by using this water-soluble catalyst requires only 0.01 mol% of Pd catalyst, while a wide range of aryl chlorides can be quantitatively converted into the respective coupling products by using 0.1-0.5 mol % of catalyst in pure water at 100°C. Difficult substrate combinations, such as naphthylboronic acid or 3-pyridylboronic acid and aryl chlorides are coupled at 100°C by using 0.1-0.5 mol % of catalyst in pure water to obtain the respective N-heterocycles in quantitative yields. The copper-free aqueous Sonogashira coupling of aryl bromides generates the respective tolane derivatives in > 95 % yield.
- Fleckenstein, Christoph A.,Plenio, Herbert
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p. 2701 - 2716
(2008/03/14)
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- Efficient palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids using benzoferrocenyl phosphines as supporting ligands
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Four monodentate benzoferrocenyl phosphines were studied as supporting ligands in palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids. Of these ligands, the more electron-rich and steric demanding benzoferrocenyl dicyclohexyl phosphine was found highly effective for the reaction followed by the benzoferrocenyl diisopropyl phosphine. The corresponding diethyl and diphenyl phosphines are much less active. When the dicyclohexyl phosphine was used, both electron-rich and electron-poor aryl chlorides were coupled with arylboronic acids within 1 h giving good to excellent yields. Chloro-substituted pyridines were also found highly reactive under these conditions giving excellent yields of biaryl products. Sterically hindered biaryls can also be prepared using the dicyclohexyl phosphine as ligand.
- Thimmaiah, Muralidhara,Fang, Shiyue
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p. 6879 - 6886
(2008/02/07)
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- Easily prepared air- and moisture-stable Pd-NHC (NHC = N-heterocyclic carbene) complexes: A reliable, user-friendly, highly active palladium precatalyst for the Suzuki-Miyaura reaction
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The synthesis of NHC-PdCl2-3-chloropyridine (NHC = N-heterocyclic carbene) complexes from readily available starting materials in air is described. The 2,6-diisopropylphenyl derivative was found to be highly catalytically active in alkyl-alkyl Suzuki and Negishi cross-coupling reactions. The synthesis, ease-of-use, and activity of this complex are substantial improvements over in situ catalyst generation and all current Pd-NHC complexes. The utilization of complex 4 led to the development of a reliable, easily employed Suzuki-Miyama protocol. Employing various reaction conditions allowed a large array of hindered biaryl and drug-like heteroaromatic compounds to be synthesized without difficulty.
- O'Brien, Christopher J.,Kantchev, Eric Assen B.,Valente, Cory,Hadei, Niloufar,Chass, Gregory A.,Lough, Alan,Hopkinson, Alan C.,Organ, Michael G.
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p. 4743 - 4748
(2008/02/08)
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- Modified (NHC)Pd(allyl)Cl (NHC = N-heterocyclic carbene) complexes for room-temperature Suzuki-Miyaura and Buchwald-Hartwig reactions
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A series of (NHC)Pd(R-allyl)Cl complexes [NHC: IPr = N,N′-bis(2,6- diisopropylphenyl)imidazol-2-ylidene, SIPr = N,N′-bis(2,6- diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene; R = H, Me, gem-Me2, Ph] have been synthesized and fully characterized. When compared to (NHC)Pd(allyl)Cl, substitution at the terminal position of the allyl scaffold favors a more facile activation step. This translates into higher catalytic activity in the Suzuki-Miyaura and Buchwald-Hartwig reactions, allowing for the coupling of unactivated aryl chlorides at room temperature in minutes. In the Suzuki-Miyaura reaction, aryl triflates, bromides, and chlorides react with boronic acids using very low catalyst loading. In the N-aryl amination reaction, a wide range of substrates has been coupled efficiently; primary-, secondary-, alkyl-, or aryl-amines react in high yields with unactivated, neutral, and activated aryl chlorides and bromides. In both reactions, extremely hindered substrates such as tri-ortho-substituted biaryls and tetra-ortho-substituted diarylamines can be produced without loss of activity. Finally, the present catalytic system has proven to be efficient with as low as 10 parts-per-million (ppm) of precatalyst in the Buchwald-Hartwig reaction and 50 ppm in the Suzuki-Miyaura reaction.
- Marion, Nicolas,Navarro, Oscar,Mei, Jianguo,Stevens, Edwin D.,Scott, Natalie M.,Nolan, Steven P.
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p. 4101 - 4111
(2007/10/03)
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- Suzuki-Miyaura, α-ketone arylation and dehalogenation reactions catalyzed by a versatile N-heterocyclic carbene-palladacycle complex
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The activity of the complex (IPr)PdCl(η2-N,C-C 12H7NMe2), 1 [IPr = (N,N′-bis(2,6- diisopropylphenyl)-imidazol)-2-ylidene], in the Suzuki-Miyaura cross-coupling reaction involving unactivated aryl chlorides and triflates with arylboronic acids at room temperature in technical grade 2-propanol is described. These conditions allow for the synthesis of di- and tri-ortho-substituted biaryls in very short reaction times. This complex also displays very high activity for α-ketone arylation and dehalogenation reactions of activated and unactivated aryl chlorides.
- Navarro, Oscar,Marion, Nicolas,Oonishi, Yoshihiro,Kelly III, Roy A.,Nolan, Steven P.
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p. 685 - 692
(2007/10/03)
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- Simple (imidazol-2-ylidene)-Pd-acetate complexes as effective precatalysts for sterically hindered suzuki-miyaura couplings
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(Chemical Equation Presented) A simplified synthesis of N-heterocyclic carbene (NHC)Pd-carboxylate complexes and their activity in Suzuki-Miyaura cross-coupling reactions are described. Coupling of sterically hindered aryl and activated alkyl chlorides bearing β-hydrogens has been successfully achieved.
- Singh, Rohit,Viciu, Mihai S.,Kramareva, Natalia,Navarro, Oscar,Nolan, Steven P.
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p. 1829 - 1832
(2007/10/03)
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- Palladium catalyzed Suzuki-Miyaura coupling with aryl chlorides using a bulky phenanthryl N-heterocyclic carbene ligand
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A novel bis-phenanthryl N-heterocyclic carbene (NHC) based palladium acetate catalyst was effective for the coupling of various aryl and vinyl chlorides with organoboron compounds. N,N-Bis-(2,9-dicyclohexyl-10-phenanthryl)- 4,5-dihydroimidazolium chloride 8 (H2ICP·HCl) with Pd(OAc)2 and KF·18-c-6 in THF at room temperature gave Suzuki-Miyaura coupling of aryl and vinyl chorides, including unactivated and di-ortho substituted substrates in high yields. Hindered tri- and tetra-ortho substituted products were also efficiently produced. Benzyl chloride was also found to be a useful coupling partner and trimethylboroxine was used to give methylated products. The effect of ligand, base, temperature, solvent, and reaction time are reported along with various substrates including halides and triflates.
- Song, Chun,Ma, Yudao,Chai, Qiang,Ma, Chanqin,Jiang, Wei,Andrus, Merritt B.
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p. 7438 - 7446
(2007/10/03)
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- Palladium-catalyzed arylation of α,α-disubstituted arylmethanols via cleavage of a C-C or a C-H bond to give biaryls
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The palladium-catalyzed arylation of α,α-disubstituted arylmethanols with aryl halides proceeds not only via C-H bond cleavage at the ortho-position, but also via cleavage of the sp2-sp3 C-C bond with the liberation of ketones (β-carbon elimination) to give the corresponding biaryls. Both reactions appear to occur through common arylpalladium(II) alcoholate intermediates. The results of systematic studies with respect to which C-C or C-H bond is preferentially cleaved in the arylation are reported. Among the important findings is the selective elimination of ortho-substituted aryl groups even from aryl(diphenyl)methanols due to steric reasons. Thus, various biaryls having ortho-substituents can be produced efficiently by treatment of the corresponding aryl(diphenyl or dimethyl)methanols with aryl bromides and chlorides.
- Terao, Yoshito,Wakui, Hiroyuki,Nomoto, Michiyo,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
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p. 5236 - 5243
(2007/10/03)
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