- Polyglycerol as a high-loading support for boronic acids with application in solution-phase Suzuki cross-couplings
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In this paper, we describe the usage of a soluble high-loading polyglycerol support for functionalized boronic acids without further linker design. The quantitatively formed polyglycerol boron esters were subsequently employed in homogeneous Suzuki cross-coupling reactions to give high yields (84-91%) of functional biaryls with minimal amounts of the Pd catalyst (0.2 mol %). In situ precipitation and ultrafiltration were used as simple and effective purification protocols. Furthermore, the reaction conditions were optimized by the choice of the solvent and the catalyst.
- Hebel, Andre,Haag, Rainer
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- Organozinc-mediated direct cross-coupling under microwave irradiation
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We report a direct cross-coupling reaction between (het)aryl pivalates/tosylates and di(het)arylzinc species in 2-methyltetrahydrofuran/N-methyl pyrrolidone (1:1), which occurs via C–O bond cleavage under microwave irradiation. The reaction takes place smoothly in short reaction times without the addition of any catalyst or ligand. The reaction is suitable for a broad scope of substrates and exhibits good functional group compatibility, utilizes a simple work-up procedure, and gives the desired products in high purity.
- Li, Chun-Jing
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p. 869 - 875
(2021/07/02)
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- Polysulfide Anions as Visible Light Photoredox Catalysts for Aryl Cross-Couplings
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Polysulfide anions are endowed with unique redox properties, attracting considerable attentions for their applications in alkali metals-sulfur batteries. However, the employment of these anionic species in redox catalysis for small molecule synthesis remains underdeveloped due to their moderate-poor electrochemical potential in the ground state, whereas some of them are characterized by photoabsorptions in visible spectral regions. Herein, we disclose the use of polysulfide anions as visible light photoredox catalysts for aryl cross-coupling reactions. The reaction design enables single-electron reduction of aryl halides upon the photoexcitation of tetrasulfide dianions (S42-). The resulting aryl radicals are engaged in (hetero)biaryl cross-coupling, borylation, and hydrogenation in a redox catalytic regime involving S4?-/S42- and S3?-/S32- redox couples.
- Li, Haoyu,Tang, Xinxin,Pang, Jia Hao,Wu, Xiangyang,Yeow, Edwin K. L.,Wu, Jie,Chiba, Shunsuke
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supporting information
p. 481 - 487
(2021/01/13)
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- A general palladium-catalyzed cross-coupling of aryl fluorides and organotitanium (IV) reagents
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Pd(OAc)2/1-[2-(di-tert-butylphosphanyl)phenyl]-4-methoxy-piperidine was demonstrated to effectively catalyze cross-coupling of aryl fluoride and aryl(alkyl) titanium reagent. Both electron-deficient and electron-rich aryl fluoride can react effectively with nucleophile and provide extensive functional groups tolerance. 2-Arylated product was realized by selective activation of the C–F bond. Graphic abstract: [Figure not available: see fulltext.].
- He, Xiao-Yun
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p. 823 - 832
(2021/07/19)
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- Biaryl Cross-Coupling Enabled by Photo-Induced Electron Transfer
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We report a protocol for aryl cross-coupling of electron-deficient aryl halides with electron-rich (hetero)arenes that is driven solely by violet light. This process takes advantage of formation of photo-excited state of electron-deficient aryl halides, that are reduced by electron-rich (hetero)arenes to form a pair of aryl anion and cation radicals. The resulting aryl anion radicals of aryl halides undergo mesolysis of the carbon-halogen bond to generate aryl radicals, that are coupled most likely with aryl cation radicals to afford functionalized biaryls. (Figure presented.).
- Hayashi, Hirohito,Wang, Bin,Wu, Xiangyang,Teo, Shi Jie,Kaga, Atsushi,Watanabe, Kohei,Takita, Ryo,Yeow, Edwin K. L.,Chiba, Shunsuke
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supporting information
p. 2223 - 2231
(2020/04/30)
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- UiO-66 microcrystals catalyzed direct arylation of enol acetates and heteroarenes with aryl diazonium salts in water
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UiO-66 is a classic Metal–organic framework (MOF) that constructed by zirconium cations and terephthalate with high chemical and thermal stability. Using pristine UiO-66 nanocrystals as the catalysts, the carbon–carbon bond formation based on denitrogenat
- Sun, Zhong-Hua,Chen, Wang,Qian, Bing-Bing,Wang, Liang,Yu, Binxun,Chen, Qun,He, Ming-Yang,Zhang, Zhi-Hui
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- A facile synthesis of mesoporous graphitic carbon nitride supported palladium nanoparticles as highly effective and reusable catalysts for Stille coupling reactions under mild conditions
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The development of a Stille coupling protocol that is operable under moderate conditions without using a base is highly required for the synthetic organic chemistry community, which requires an efficient nanocatalyst. In this respect, addressed herein is a facile one-pot synthesis of mesoporous graphitic carbon nitride (mpg-CN) supported Pd NPs, denoted as mpg-CN/Pd hereafter, and investigation of their catalytic activity in Stille cross-coupling reactions for the first time. It has been demonstrated that mpg-CN nanosheets can serve as not only a support material but also a stabilizer for the generation of 4.5 nm Pd NPs. The ecofriendly generated heterogeneous nanocatalyst was characterized by TEM, XRD, XPS, BET surface area and ICP-MS analysis. The mpg-CN/Pd nanocatalysts showed high activity in the Stille coupling reaction of a variety of electron-deficient and electron-rich aryl iodides/bromides and two different organostannanes with a wide substrate scope to afford the corresponding biaryls without using any bases and additional ligands under relatively mild conditions. The catalyst can be easily recovered from the reaction medium by centrifugation. It can be reused at least 5 times without any loss of activity.
- Cetin, Sultan,Kalay, Erbay,Kolemen, Safacan,Metin, ?nder
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p. 6714 - 6723
(2020/05/16)
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- Diamines as interparticle linkers for silica-titania supported PdCu bimetallic nanoparticles in Chan-Lam and Suzuki cross-coupling reactions
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A series of highly efficient amine functionalized SiO2-TiO2 supported bimetallic PdCu catalysts with varied metal composition have been synthesized. Ethane-1,2-diamine, butane-1,4-diamine and hexane-1,6-diamine were employed as interparticle linkers for amine functionalization of a SiO2-TiO2 support material so as to study the effect of pendant chain length on stabilization and immobilization of bimetallic nanoparticles. The shortest carbon chain length on the support provided the best results, which may be due to the trapping of metal nanoparticles more efficiently by the basic nitrogen sites. The catalytic activities of these materials were evaluated for C-N and C-C coupling reactions. The most active catalyst, Pd1Cu1@12DA-STS, was characterized by various techniques including SEM, HR-TEM, ICP-AES, XRD, FTIR, EDX, CHN analysis and TGA studies. Moreover, the synthesized catalyst was found to be recyclable for up to five runs without significant loss of activity.
- Jamwal, Babita,Kaur, Manpreet,Sharma, Harsha,Khajuria, Chhavi,Paul, Satya,Clark
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p. 4919 - 4928
(2019/03/26)
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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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- Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
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Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
- Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 4364 - 4369
(2019/05/10)
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- Recyclable cellulose-palladium nanoparticles for clean cross-coupling chemistry
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Cheap, recyclable, and robust cellulose-palladium nanoparticles were developed and fully characterized by FTIR, TEM, XPS, TGA, and NMR. The nanoparticles enabled cross-coupling chemistry in a truly general fashion i.e., Suzuki-Miyaura, Heck, Sonogashira, and C-H activation. Notably, all types of transformations were achieved with a single type of nanocatalyst. Complete recyclability of the catalyst and low traces of palladium in the product demonstrates the greenness of the protocol.
- Lu, Zhichao,Jasinski, Jacek B.,Handa, Sachin,Hammond, Gerald B.
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supporting information
p. 2748 - 2752
(2018/04/27)
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- Non-Directed Cross-Dehydrogenative (Hetero)arylation of Allylic C(sp3)?H bonds enabled by C?H Activation
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Herein, we report the selective, non-directed and cross-dehydrogenative coupling of allylic C(sp3)?H bonds with C(sp2)?H bonds of (hetero)arenes. The methodology employs olefins and (hetero)arenes which are abundantly available chemical feedstocks, and could be applied in late-stage functionalization reactions of pharmaceuticals. Furthermore, the system exclusively delivers the allylic C?C coupling products highlighting the preservation of the olefin substitution pattern for further derivatization.
- Lerchen, Andreas,Knecht, Tobias,Koy, Maximilian,Ernst, Johannes B.,Bergander, Klaus,Daniliuc, Constantin G.,Glorius, Frank
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supporting information
p. 15248 - 15252
(2018/10/20)
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- One-step highly selective borylation/Suzuki cross-coupling of two distinct aryl bromides in pure water
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A Na2PdCl4-catalysed B2(OH)4-mediated direct cross-coupling of two distinct aryl bromides in pure water is described. This one-step borylation/Suzuki method exhibits an outstanding cross-coupling selectivity and no tendency to produce homocoupling products, therefore leading to biaryls and heterobiaryls in moderate to good yields. Moreover, the reaction has high regio-selectivity and can be scaled-up. Using such a simple, economical and practical protocol, the unsymmetrical diarylation of 3,5-dibromopryidine is achieved.
- Xu, Shan Dong,Sun, Fang Zhou,Deng, Wei Hang,Hao, Han,Duan, Xin Hong
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supporting information
p. 16464 - 16468
(2018/10/24)
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- Synthesis of bench-stable solid triorganoindium reagents and reactivity in palladium-catalyzed cross-coupling reactions
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Bench-stable solid triorganoindium compounds have been prepared by coordination with 4-(dimethylamino)pyridine (DMAP). The solid R3In(DMAP) complexes are obtained from the corresponding solution of R3In in quantitative yield and can
- Gil-Negrete, José M.,Pérez Sestelo, José,Sarandeses, Luis A.
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supporting information
p. 1453 - 1456
(2018/02/19)
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- C-H arylation reactions through aniline activation catalysed by a PANI-g-C3N4-TiO2 composite under visible light in aqueous medium
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A PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for radical C-H arylation reactions. The arylation process involved coupling of in situ generated aryl diazonium salts from aniline with heteroarenes, enol acetates or benzoquinones under visible light in aqueous medium or pure water. A broad range of substrates survived the reaction conditions to provide the desired products in moderate to good yields. Scale-up (10 mmol) synthesis was also achieved. This semiconductor photocatalyst showed good photocatalytic performance and stability. Recycle studies showed that this composite could be readily recovered and a slight decrease in the catalytic activity was observed after ten consecutive runs.
- Wang, Liang,Shen, Jun,Yang, Sen,Liu, Wenjie,Chen, Qun,He, Mingyang
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supporting information
p. 1290 - 1296
(2018/03/26)
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- Visible-Light-Promoted Arylation Reactions Photocatalyzed by Bismuth(III) Oxide
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Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol-%), this cheap and nontoxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the process admits straightforward scale-up (10 mmol; 1 mol-% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 also catalyzed the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes.
- Buglioni, Laura,Riente, Paola,Palomares, Emilio,Pericàs, Miquel A.
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supporting information
p. 6986 - 6990
(2017/12/26)
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- Wavelength Selective Generation of Aryl Radicals and Aryl Cations for Metal-Free Photoarylations
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Photochemical reactions have become an important tool for organic chemists. Visible (solar) light can be conveniently adopted, however, only when using colored organic compounds or in photocatalyzed processes induced by visible light absorbing photocatalysts. Herein we demonstrate that a photolabile, colored moiety could be incorporated in a colorless organic compound with the aim of generating highly reactive intermediates upon exposure to visible (solar) light. Arylazo sulfones, colored thermally stable derivatives of aryl diazonium salts, were used as valuable substrates for the photoinduced metal-free synthesis of (hetero)biaryls with no need of a (photo)catalyst or of other additives to promote the reaction. Noteworthy, selective generation of aryl radicals and aryl cations can be attained at will by varying the irradiation conditions (visible light for the former and UVA light for the latter).
- Crespi, Stefano,Protti, Stefano,Fagnoni, Maurizio
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p. 9612 - 9619
(2016/11/02)
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- Novel heterogeneous catalyst systems based on Pd(0) nanoparticles onto amine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs]: Synthesis, characterization and catalytic activity toward C-C and C-S coupling reactions in water under limiting basic conditions
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Novel heterogeneous catalyst systems based on the immobilization of Pd(0) nanoparticles onto ethylene diamine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs] are reported with a view to introduce new synthetic routes under base-free conditions. The base functionalized organic/inorganic hybrid provides specific basic sites for the reactions to occur under base-free or less basic conditions, and that too with excellent yields. Moreover, the basic nitrogen sites present on the substrate can effectively stabilize and enhance the activity of Pd(0) nanoparticles by preventing their agglomeration and controlling their size. All the catalysts were characterized by TGA and FTIR analysis and the most active catalyst, [Pd(0)-EDA/SC-2] was further characterized by SEM, TEM, HRTEM, EDX, CHN and XRD studies. Additionally, it is shown that the Pd(0)-EDA/SCs exhibits excellent activity under limiting basic conditions for the C-C and C-S coupling reactions employing water as the "Green solvent". Furthermore, the novel catalyst could be recovered in a facile manner from the reaction mixture and could be reused up to five times without significant loss of catalytic activity.
- Bhardwaj, Madhvi,Sahi, Seema,Mahajan, Hitesh,Paul, Satya,Clark, James. H.
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- Fluorosolvatochromism of furanyl- and thiophenyl-substituted acetophenones
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A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy.
- Friebe, Nadine,Schreiter, Katja,Kübel, Joachim,Dietzek, Benjamin,Moszner, Norbert,Burtscher, Peter,Oehlke, Alexander,Spange, Stefan
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p. 5171 - 5179
(2015/07/07)
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- Palladium nanoparticles supported on graphene and reduced graphene oxide as efficient recyclable catalyst for the Suzuki-Miyaura reaction of potassium aryltrifluoroborates Dedicated to the memory of Prof. Carlos F. Barbas III.
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Palladium nanoparticles supported on graphene platelets have been efficiently used as catalyst in the Suzuki-Miyaura coupling between aryl bromides and potassium aryltrifluoroborates using 0.1 mol% of Pd and potassium carbonate as base in MeOH/H2O as solvent at 80 °C. The reaction can be performed using conventional and microwave heating showing the catalyst high reusability, particularly with microwaves, where lower aggregation of Pd nanoparticles has been observed. A dissolution/re-deposition catalytic mechanism is proposed, based on the fact that palladium leaching to the solution is detected under microwave irradiation.
- Gómez-Martínez, Melania,Buxaderas, Eduardo,Pastor, Isidro M.,Alonso, Diego A.
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- General suzuki coupling of heteroaryl bromides by using tri-tert-butylphosphine as a supporting ligand
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A general procedure for the fast Suzuki coupling of major families of heteroaryl bromides was realized by using Pd(OAc)2/PtBu3 as the catalyst. Many couplings were finished within minutes at room temperature in n-butanol. Different from previous studies, three typical heteroaryl bromides were systematically examined in couplings of various heteroaryl and aryl boronic acids. A fast, general coupling of heteroaryl bromides is realized by using a single palladium catalyst supported by tri-tert-butylphosphine.
- Zou, Yinjun,Yue, Guizhou,Xu, Jianwei,Zhou, Jianrong
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supporting information
p. 5901 - 5905
(2015/03/30)
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- A general approach to N-heterocyclic carbenes with a fused tetracyclic core: Ligands for suzuki-miyaura cross-coupling reaction
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The synthesis of an N-heterocyclic carbene (NHC) based on a tetracyclic scaffold by using simple, general, and scalable chemistry is disclosed. The developed route is suitable for introducing multiple substitutions on the tetracyclic scaffold. The utility of the present NHC as a ligand in the Suzuki-Miyaura cross-coupling reaction is demonstrated with a low catalyst loading. Copyright
- Sutar, Revannath L.,Kumar, Vinod,Shingare, Rahul D.,Thorat, Shridhar,Gonnade, Rajesh,Reddy, D. Srinivasa
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supporting information
p. 4482 - 4486
(2014/08/05)
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- An efficient palladium N-heterocyclic carbene catalyst allowing the suzuki-miyaura cross-coupling of aryl chlorides and arylboronic acids at room temperature in aqueous solution
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The application of a highly active Pd-NHC catalyst for the Suzuki-Miyaura cross-coupling of a broad variety of electronically activated and deactivated aryl chlorides with different arylboronic acids in excellent yields is described. This catalyst can be handled under aerobic conditions, is active with low catalyst loadings at room temperature and in an aqueous reaction medium and allows the application of cheap potassium carbonate as the base.
- Rajabi, Fatemeh,Thiel, Werner R.
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p. 1873 - 1877
(2014/06/09)
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- A general catalyst for Suzuki-Miyaura and Sonogashira reactions of aryl and heteroaryl chlorides in water
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We report the synthesis of 2-(3-sulfonatomesityl)-5-sulfonatoindenyl) dicyclohexylphosphine hydrate sodium salt and its use in palladium-catalyzed Suzuki-Miyaura and Sonogashira coupling reactions in water (and biphasic water-organic solvent mixtures) to prepare a variety of functionalized biaryls and aryl alkynes in excellent yield. This journal is the Partner Organisations 2014.
- Peng, Hui,Chen, Ya-Qin,Mao, Shu-Lan,Pi, Yun-Xiao,Chen, You,Lian, Ze-Yu,Meng, Tong,Liu, Sheng-Hua,Yu, Guang-Ao
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supporting information
p. 6944 - 6952
(2014/09/29)
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- Efficient one-pot cross-coupling of two aryl halides by stannylation/stille reaction in water under microwave irradiation
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A simple and highly efficient one-pot approach has been developed for the Pd(PPh3)4-catalyzed cross-coupling of two different aryl or heteroaryl bromides/iodides. This method involves the combined use of microwave irradiation and water as a single solvent to achieve sequential stannylation and Stille cross-coupling reactions, which allows rapid access to a wide variety of biaryls in good to high yields. Furthermore, utilizing this step-economical protocol, 2,5-dibromopyridine was iteratively diarylated and the Boscalid intermediate was also synthesized in a one-pot manner. Copyright
- Tan, Xin,Zhou, Zi Jie,Zhang, Jia Xin,Duan, Xin Hong
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supporting information
p. 5153 - 5157
(2014/09/29)
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- Palladium-catalyzed acetylation of arenes
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A simple method for the preparation of aryl methyl ketones is reported. The transformation involves the Pd-catalyzed coupling of an acyl anion equivalent, acetyltrimethylsilane, with aryl bromides to afford the corresponding acetylated arenes in synthetically useful yields. The methodology is tolerant of heterocycles and provides a new method for arene functionalization.
- Ramgren, Stephen D.,Garg, Neil K.
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supporting information
p. 824 - 827
(2014/03/21)
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- Reusable, highly active heterogeneous palladium catalyst by convenient self-encapsulation cross-linking polymerization for multiple carbon-carbon cross-coupling reactions at ppm to ppb palladium loadings
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Designing reusable high-performance heterogeneous palladium (Pd) catalysts via convenient, economic synthesis is of great importance to the industrial applications of various carbon-carbon crosscoupling reactions. We demonstrate herein a convenient one-pot self-encapsulation synthesis of a heterogeneous Pd catalyst [Pd@PDEB, PDEB = poly(1,3-diethynylbenzene)] directly from commercially available, economic precursors. In the synthesis, the formation of the cross-linked polymer networks and Pd encapsulation are accomplished simultaneously, turning a homogeneous Pd polymerization catalyst into the heterogeneous cross-coupling catalyst. As a unique, practical heterogeneous catalyst, Pd@PDEB shows remarkably high activity, high reusability, and high versatility towards at least four types of cross-coupling reactions (Suzuki-Miyaura, Stille, allylic arylation, and Mizoroki-Heck reactions) with even difficult reactants (aryl chlorides and heteroaryl halides) under aerobic conditions with Pd loadings down to ppm or even ppb levels. Evidences from hot filtration and 3-phase tests demonstrate the heterogeneous nature of the catalyst with very low Pd leaching and negligible contributions of leached homogeneous Pd species towards the coupling reactions.
- Donga, Zhongmin,Yea, Zhibin
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p. 3401 - 3414
(2015/02/05)
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- One-by-one hydrogenation, cross-coupling reaction, and Knoevenagel condensations catalyzed by PdCl2 and the downstream palladium residue
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A novel catalyst-economic strategy with a recovered palladium catalyst was successfully applied for multi-task and maximum reuse in different types of one-by-one downstream reactions, from catalytic hydrogenation to Suzuki and Sonogashira-type cross-coupling reactions, Knoevenagel condensations, and trans-Knoevenagel-like condensations.
- Wang, Hu,Li, Li,Bai, Xing-Feng,Deng, Wen-Hui,Zheng, Zhan-Jiang,Yang, Ke-Fang,Xu, Li-Wen
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supporting information
p. 2349 - 2355
(2013/09/12)
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- Palladium, iridium and ruthenium complexes with acyclic imino-N-heterocyclic carbenes and their application in aqua-phase Suzuki-Miyaura cross-coupling reaction and transfer hydrogenation
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Palladium (4a-4c), iridium (5a-5c) and ruthenium (6a-6c) complexes have been prepared by in situ transmetalation from the corresponding silver complexes of acyclic imino-functionalized imidazolium chlorides [1-(Me)-imidazolium-3- {C(p-CH3-Ph)N(Ar)}]Cl (3) (Ar = 2,4,6-trimethylphenyl (3a), 2,6-diisopropylphenyl (3b) and phenyl (3c)) with [Pd(COD)Cl2], [Cp*IrCl2]2 or [Ru(p-cymene)Cl2] 2, respectively. Iridium and ruthenium complexes, 5a[PF 6]-5c[PF6], 6a[PF6]-6c[PF6], 6c[BF4], 6c[BPh4] and 6c[NTf2], were obtained directly from 5a-5c and 6a-6c through an anion-exchange process with KPF 6, NaBF4, NaBPh4 and LiNTf2 (bis(trifluoromethylsulfonyl)imide lithium), respectively. All complexes were characterized by FT-IR, 1H and 13C NMR spectroscopy and elemental analysis. Crystal structures of 4a, 5a and 6c[NTf2] show that five-membered chelate ring is formed in these complexes by the coordination of the carbene carbon and the imino nitrogen atom, and the latter two are cationic compounds with Cl- and NTf2- as counteranion respectively. The catalytic performance of Pd complexes for Suzuki-Miyaura cross-coupling reactions in pure water and Ir and Ru complexes for transfer hydrogenation of ketones and imines was tested in a wide scope of substrates. Pd complex 4b with the largest steric hinder exhibited the best performance to gain moderate to excellent yields on catalyzing Suzuki-Miyaura cross-coupling of aryl chlorides and arylboronic acids in water. While in transfer hydrogenation of various ketones, all the Ir and Ru complexes were effective with good to excellent yields. Among all these complexes, 6c[PF 6] was found most effective, and moderate yields could be obtained even in the transfer hydrogenation of imines. Moreover, different counteranions of Ru complexes are influential on catalyzing the transfer hydrogenation, with the sequence of PF6- ≈ BF4- > BPh4- > Cl- > NTf2 -.
- Guo, Xu-Qing,Wang, Ya-Nong,Wang, Dong,Cai, Li-Hua,Chen, Zhen-Xia,Hou, Xiu-Feng
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p. 14557 - 14567
(2013/01/16)
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- Room-temperature Suzuki-Miyaura coupling of heteroaryl chlorides and tosylates
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Suzuki-Miyaura coupling of heteroaryls is an important method for the preparation of compound libraries for medicinal chemistry and materials research. Although many catalysts have been developed, none of them have been generally applicable to the coupling reactions of heteroaryl chlorides and tosylates at room temperature. We discovered that a catalyst combination of Pd(OAc)2 and XPhos (2-dicyclohexylphosphanyl-2',4',6'- triisopropylbiphenyl) could efficiently catalyze these couplings. Besides the choice of catalyst, the use of hydroxide bases in an aqueous alcoholic solvent was essential for fast couplings. These conditions promoted fast release of active catalyst (XPhos)Pd0, and accelerated the transmetalation in the catalytic cycle. Most of the major families of heteroaryl chlorides (31 examples) and tosylates (17 examples) reached full conversion within minutes to hours at room temperature. The method could be easily scaled up for gram-scale synthesis. Furthermore, we examined the relative reactivity of coupling partners in whole reactions. Electron-rich heteroaryl chlorides and tosylates reacted more slowly than electron-deficient ones, in the order of indole, pyrrole furan, thiophene > pyridine. Similarly, electron-deficient arylboronic acids were less reactive than electron-neutral and electron-rich ones. The reactivity trends from this study can help to choose appropriate coupling partners for Suzuki reactions.
- Yang, Junfeng,Liu, Sijia,Zheng, Jian-Feng,Zhou, Jianrong
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supporting information
p. 6248 - 6259,12
(2020/09/16)
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- Direct 2-arylation of thiophene using low loading of a phosphine-free palladium catalyst
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The direct coupling of aryl halides with thiophene would be a considerable advantage for sustainable development because of only HBr associated with a base as by-product is formed and the number of steps to prepare these compounds is less than in more cla
- Bensaid, Souhila,Roger, Julien,Beydoun, Kassem,Roy, David,Doucet, Henri
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experimental part
p. 3524 - 3531
(2011/09/16)
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- Ni(COD)2/PCy3 catalyzed cross-coupling of aryl and heteroaryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates in THF at room temperature
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Reaction conditions for the Ni(COD)2/PCy3 catalyzed cross-coupling of aryl neopentylglycolboronates with aryl mesylates were developed. By using optimized reaction conditions, Ni(COD)2/PCy 3 was shown to be a versatile catalyst for the cross-coupling of a diversity of aryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates containing both electron-donating and electron-withdrawing substituents in their para, ortho, and meta positions in THF at room temperature. This Ni-catalyzed cross-coupling of aryl neopentylglycolboronates is also effective for the synthesis of heterobiaryls and biaryls containing electrophilic functionalities sensitive to organolithium and organomagnesium derivatives. In combination with the recently developed Nicatalyzed neopentylglycolborylation, all Ni-catalyzed routes to functional biaryls and heterobiaryls are now easily accessible (Figure presented).
- Leowanawat, Pawaret,Zhang, Na,Resmerita, Ana-Maria,Rosen, Brad M.,Percec, Virgil
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experimental part
p. 9946 - 9955
(2012/01/15)
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- Negishi cross-coupling reaction catalyzed by an aliphatic, phosphine based pincer complex of palladium. biaryl formation via cationic pincer-type Pd IV intermediates
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The aliphatic, phosphine-based pincer complex [(C10H 13-1,3-(CH2P(Cy2)2)Pd(Cl)] (1) is a highly active Negishi catalyst, enable to quantitatively couple various electronically activated, non-activated, deactivated, sterically hindered and functionalized aryl bromides with various diarylzinc reagents within short reaction times and low catalyst loadings. Experimental observations strongly indicate that a molecular mechanism is operative with initial chloride dissociation of 1 and formation of the cationic T-shaped 14e- complex [(C10H13-1,3-(CH2P(C6H 11)2)2)Pd]+ (B), which undergoes oxidative addition of an aryl bromide (Ar′Br) to yield the cationic, penta-coordinated aryl bromide pincer complexes of type [(C10H 13-1,3-(CH2P(Cy2)2)Pd(Br) (aryl′)]+ (C) with the metal center in the oxidation state of +IV and the aryl unit in cis position relative to the aliphatic pincer core. Subsequent transmetalation with Zn(aryl)2 result in the cationic diaryl pincer complexes of type [(C10H13-1,3-(CH 2P(Cy2)2)Pd(aryl)(aryl′)]+ (D), which reductively eliminate the coupling products, thereby regenerating the catalyst. The neutral square planar aryl pincer complex - a possible key intermediate in the catalytic cycle - was found to be reversibly formed in the reaction mixture but is not involved in the catalytic mechanism. Similarly, palladium nanoparticles as the catalytically active form of 1 could have been excluded. The Royal Society of Chemistry 2011.
- Gerber, Roman,Blacque, Olivier,Frech, Christian M.
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experimental part
p. 8996 - 9003
(2011/10/31)
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- Ionic liquid supported organotin reagents: Green tools for stille cross-coupling reactions with brominated substrates
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Efficiency of ionic liquid supported organotin reagents in Stille cross-coupling reactions involving aryl bromides has been investigated. In a general manner, products were isolated with good yields by using a very simple catalytic system without the need of solvent, ligand, or additives. The organotin compounds were recycled without loss of activity and the contamination by tin was limited and controlled ([Sn] 3 ppm). Clean tin's good! Efficiency of ionic liquid supported organotin reagents in Stille cross-coupling reactions involving aryl bromides has been investigated. Products were isolated with good yields by using a verysimple catalytic system. Organotin compounds were recycled without loss of activity and the contamination by tin was limited ([Sn] 3 ppm).
- Louaisil, Nicolas,Pham, Phuoc Dien,Boeda, Fabien,Faye, Djibril,Castanet, Anne-Sophie,Legoupy, Stephanie
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supporting information; experimental part
p. 143 - 149
(2011/03/18)
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- Palladium-catalyzed cross-coupling reaction of heteroaryltriolborates with aryl halides for synthesis of biaryls
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Cyclic triolborates possessing a heteroaromatic ring on the boron atom [ArB(OCH2)3CHCH3]M (M=K, Na, Li) were prepared in high yields from heteroarylboronic acids, 1,1,1-tris(hydroxymethyl)ethane (triol) and KOH or NaH. The corresponding lithium salts were synthesized from aryllithiums, B(OMe)3 and triol. They were air-stable white solids that were convenient for handling in air. High performance of these triolborates for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions with haloarenes. Although the use of heteroarylboronic acids often results in very low yields due to competitive hydrolytic B-C bond cleavage with water under typical conditions using aqueous bases, triolborates possessing a 2-pyridyl, 3-pyridyl or 2-thiophenyl ring afforded biaryls in high yields at 50-120C in anhydrous DMF. There was a strong accelerating effect of CuI for reactions of 2-and 3-pyridylborate derivatives, whereas 2-thiophenyl derivatives reacted smoothly resulting in high yields in the absence of CuI.
- Yamamoto, Yasunori,Takizawa, Miho,Yu, Xiao-Qiang,Miyaura, Norio
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experimental part
p. 359 - 368
(2010/04/27)
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- Palladium nanoparticles in ionic liquid by sputter deposition as catalysts for suzuki-miyaura coupling in water
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Palladium nanoparticles in an ionic liquid prepared readily by sputter deposition efficiently catalyze the Suzuki-Miyaura coupling of hydrophobic as well as hydrophilic aryl halides in water.
- Oda, Yoshiro,Hirano, Koji,Yoshii, Kazuki,Kuwabata, Susumu,Torimoto, Tsukasa,Miura, Masahiro
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supporting information; experimental part
p. 1069 - 1071
(2011/01/09)
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- SLOW RELEASE OF ORGANOBORONIC ACIDS IN CROSS-COUPLING REACTIONS
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A method of performing a chemical reaction includes reacting a compound selected from the group consisting of an organohalide and an organo-pseudohalide, and a protected organoboronic acid represented by formula (I) in a reaction mixture: R1-B-T; where R1 represents an organic group, T represents a conformationalIy rigid protecting group, and B represents boron having sp3 hybridization. When unprotected, the corresponding organoboronic acid is unstable by the boronic acid neat stability test. The reaction mixture further includes a base having a pKB of at least 1 and a pal ladium catalyst. The method further includes forming a cross-coupled product in the reaction mixture.
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Page/Page column 65-66, 68
(2010/04/27)
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- Palladium on charcoal-catalyzed ligand-free Stille coupling
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An efficient ligand-free Stille coupling reaction catalyzed by palladium on charcoal was developed. Tetraphenyltin was reacted with a variety of aryl halides including aryl chlorides using LiCl as an additive. The reactions of tributyl organotin compounds with aryl iodides were effectively expedited by the addition of LiF. These reactions efficiently proceeded without a phosphine or arsenic ligand and no leached palladium was detected in the reaction mixture.
- Yabe, Yuki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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experimental part
p. 8654 - 8660
(2010/11/19)
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- Self-assembly of palladium nanoparticles: Synthesis of nanobelts, nanoplates and nanotrees using vitamin B1, and their application in carbon-carbon coupling reactions
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An environmentally friendly one-step method to synthesize palladium (Pd) nanobelts, nanoplates and nanotrees using vitamin B1 without using any special capping agents at room temperature is described. This greener method, which uses water as a benign solvent and vitamin B1 as a reducing agent, can be extended to prepare other noble nanomaterials such as gold (Au) and platinum (Pt). Depending upon the Pd concentration used for the preparation, Pd crystallized in different shapes and sizes. A lower Pd concentration yielded a plate-like structure where thickness of these plates varied from 100 nm to 250 nm with a length of several microns. An increase in concentration of Pd resulted in the formation of tree-like structures. The Pd plates are grown on a single Pd nanorod backbone mimicking the leaf-like structures. Upon further increase in Pd concentration, Pd nanoplates started becoming thicker by vertically aligning themselves together to form ball-like structures. The synthesized self-assembled Pd nanoparticles were characterized using, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV spectroscopy. The Pd nanoparticles showed excellent catalytic activity for several C-C bond forming reactions such as Suzuki, Heck and Sonogashira reactions under microwave (MW) irradiation conditions. The Royal Society of Chemistry 2009.
- Nadagouda, Mallikarjuna N.,Polshettiwar, Vivek,Varma, Rajender S.
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experimental part
p. 2026 - 2031
(2010/04/26)
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- Ligand-less palladium-catalyzed direct 5-arylation of thiophenes at low catalyst loadings
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Ligand-less Pd(OAc)2 provides a very efficient catalyst for the direct 5-arylation of thiophene derivatives. With this catalyst, a low palladium concentration (0.1-0.001 mol%) should be employed in order to obtain high yields of coupling products. At higher concentrations a fast formation of inactive "Pd black" generally occurs. Substrates/catalysts ratios up to 100000 can be employed with the most reactive aryl bromides. A very wide variety of functional groups is tolerated on both coupling partners. The major waste of this reaction is HBr associated with KOAc. Therefore this procedure is more economically and environmentally attractive than the traditional cross-coupling procedures employing organometallic derivatives.
- Roger, Julien,Pozgan, Franc,Doucet, Henri
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experimental part
p. 425 - 432
(2010/04/22)
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- Fluoride-triggered indium-mediated synthesis of (hetero)biaryls
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A simple method for the preparation of triorganoindium reagents under mild conditions based in indium-silicon exchange is described.
- Font-Sanchis, Enrique,Sastre-Santos, Angela,Fernandez-Lazaro, Fernando
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experimental part
p. 2470 - 2473
(2009/12/02)
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- Canopied trans-chelating bis(N-heterocyclic carbene) ligand: Synthesis, structure and catalysis
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The terphspan scaffold was employed to support a bis(N-heterocyclic carbene) ligand (1) that provides a m-terphenyl canopy over one side of its metal complexes. Single-crystal X-ray diffraction studies on a silver complex of {[Ag(1)]AgBr2}2 revealed an unusual tetranuclear silver core with a Ag-Ag bond distance of 3.0241(8) with 1 as a trans-chelating ligand (C-Ag-C = 171°). A preliminary X-ray structure of pseudo-square planar [PdCl2(1)] showed a similar binding mode of 1 (C-Pd-C = 177°). High yields were obtained in Suzuki-Miyaura coupling reactions utilizing [PdCl2(1)] as the procatalyst and the results were compared with analogous complexes of trans-spanning diphosphine (2) and diphosphinite (3) complexes. The diphosphinite complex, [PdCl2(3)], decomposes to [μ-ClPd(PPh2OH)(PPh2O)]2 at room temperature. The Royal Society of Chemistry 2009.
- Morgan, Brad P.,Galdamez, Gabriela A.,Gilliard Jr., Robert J.,Smith, Rhett C.
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experimental part
p. 2020 - 2028
(2009/05/15)
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- One-pot Negishi cross-coupling reactions of in situ generated zinc reagents with aryl chlorides, bromides, and triflates
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(Chemical Equation Presented) In situ generated aryl, heteroaryl, alkyl, or benzylic poly-functional zinc reagents obtained by the addition of zinc and LiCl to the corresponding organic iodides undergo smooth Pd(0)-catalyzed cross-coupling reactions with
- Sase, Shohei,Jaric, Milica,Metzger, Albrecht,Malakhov, Vladimir,Knochel, Paul
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supporting information; experimental part
p. 7380 - 7382
(2009/05/07)
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- Direct coupling of arenes and iodoarenes catalyzed by a rhodium complex with a strongly π-accepting phosphite ligand
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A new rhodium-based catalytic system for the direct C-H coupling of arenes and iodoarenes that shows high activity with reasonably broad scope was developed. Under the catalytic influence of RhCl(CO){P[OCH(CF3)2]3}2 and Ag2CO3, the direct C-H arylation of heteroarenes and arenes took place with iodoarenes to afford a range of biaryls in good to excellent yields with high regioselectivity. Thiophenes, furans, pyrroles, indoles, and alkoxybenzenes are applicable to this arylation protocol.
- Yanagisawa, Shuichi,Sudo, Tomoko,Noyori, Ryoji,Itami, Kenichiro
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p. 6073 - 6081
(2008/09/21)
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- A robust method for the Hiyama-type coupling of arylsiloxanes and disiloxanes with aryl halides
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Palladium catalysed Hiyama-type coupling of aryl disiloxanes or aryl silanols with aryl halides in the presence of stoichiometric silver(I) oxide and catalytic TBAF allows the rapid preparation of biaryls in moderate to high yield under mild thermal or microwave irradiation conditions.
- Napier, Spencer,Marcuccio, Sebastian M.,Tye, Heather,Whittaker, Mark
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p. 3939 - 3942
(2008/09/21)
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- Cyclic triolborates: Air- and water-stable ate complexes of organoboronic acids
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(Chemical Equation Presented) A borate in the hand is a convenient reagent for palladium- and copper-catalyzed C-C and C-N bond-forming reactions, especially when, like the title bench-stable complexes, it demonstrates high transmetalation efficiency. Cyclic triolborates can be synthesized readily from organoboronic acids (see scheme), can be handled and stored without special precautions, and are relatively soluble in organic solvents.
- Yamamoto, Yasunori,Takizawa, Miho,Yu, Xiao-Qiang,Miyaura, Norio
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p. 928 - 931
(2008/09/20)
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- Palladium/tetraphosphine catalyzed suzuki cross-coupling of heteroarylboronic acids with aryl halides
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(Chemical Equation Presented) cis,cis,cis-1,2,3,4- Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C3H 5)]2 efficiently catalyses the Suzuki reaction of heteroarylboronic acids with aryl bromides and also the coupling of arylboronic acids with heteroaryl bromides. The coupling of thiophene- or benzothiopheneboronic acids, furan- or benzofuranboronic acids and 3-pyridineboronic acid with a variety of aryl bromides gave the corresponding coupling products in good yields. However, in most cases, better results in terms of ratio substrate/catalyst were obtained for the reverse reaction using heteroaryl bromides with arylboronic acids.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
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p. 109 - 118
(2008/09/18)
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- Benzimidazolium-pyrazole-palladium(II) complexes: New and efficient catalysts for Suzuki, Heck and Sonogashira reactions
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Three unsymmetrical benzimidazoliumpyrazole N-N ligands 2-(1-propylbenzimidazolylmethyl)-3,5-di-R-pyrazole (R=H, Me, t-Bu) have been conveniently prepared and structurally analyzed. The solid lattice packingof the R=Me compound at 223 K reveals one-dimensional "zig-zag" water chains stabilized by organic molecular channels through N...H-O and O-H...O bonding. These hybrid ligands add to palladium(II) to give high yields of air-stable complexes that are fully characterized by NMR, ESI, and X-ray single-crystal crystallography. They are active Suzuki catalysts at room temperature towards cross-couplingof unactivated aryl bromides and 5- or 6-membered heteroaryl bromides with arylboronic acids with turnover frequencies (TOF) reachingas high as 60,000 h-1. Their catalytic efficiency is significantly better than that of the C-N carbene-imidazole analogue. These catalysts are also active in Heck and Sonogashira cross-coupling reactions of aryl bromides giving the desired products in good yields. These results suggested that these Pd(II) complexes with N-based hybrid ligands are versatile and efficient catalysts for different types of cross-couplingreactio ns under aerobic conditions.
- Li, Fuwei,Hor, T. S. Andy
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experimental part
p. 2391 - 2400
(2009/10/08)
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- Isolation of an [SNS]Pd(II) pincer with a water ladder and its Suzuki coupling activity in water
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A water-compatible Pd(II) pincer with a hybrid [SNS]-donor set, [L 1PdCl]Cl·2H2O [L1 = bis-(2-(i- butylsulfanyl)-ethyl)-amine] has been isolated and crystallographically characterized; its solid lattice at 223 K contains a
- Bai, Shi-Qiang,Hor, T. S. Andy
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experimental part
p. 3172 - 3174
(2009/02/04)
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