- Structure-activity relationship of N-heterocyclic carbene-Pd(II)-imidazole complexes in Suzuki-Miyaura coupling between 4-methoxyphenyl chloride and phenylboronic acid
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A series of N-heterocyclic carbene-PdCl2-imidazole [NHC-Pd(II)-Im] complexes were synthesized and the structure of most of them was unambiguously determined by X-ray single-crystal diffraction. The structure-activity relationship of these complexes was investigated for the Suzuki-Miyaura coupling between 4-methoxyphenyl chloride and phenylboronic acid, and the effect of the NHCs and Im moieties were fully discussed. The sterically hindered IPr-based complex showed the highest catalytic activity. Copyright
- Lv, Huan,Zhu, Lei,Tang, Yi-Qiang,Lu, Jian-Mei
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- Porphyrin-based polymer-supported palladium as an excellent and recyclable catalyst for Suzuki–Miyaura coupling reaction in water
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A porphyrin-based polymer with high surface area was synthesized using 5,10,15,20-tetraphenylporphyrin through a one-pot Friedel–Crafts alkylation reaction. Pd(II) was successfully supported on this polymer. This strategy provides an easy approach to produce highly stable Pd–porphyrin-based polymer. The resulting Pd catalyst was characterized using Fourier transform infrared and X-ray photoelectron spectroscopies, thermogravimetric analysis, scanning and transmission electron microscopies and N2 adsorption–desorption measurements. This porphyrin-based polymer-supported Pd was used as a heterogeneous catalyst for Suzuki–Miyaura coupling reaction in water. The results demonstrated that this Pd catalyst indeed exhibited excellent catalytic activity and recycling performance in water, even for inactive aryl chloride substrate. A new heterogeneous strategy for catalyzing the Suzuki–Miyaura reaction in water is provided.
- Chen, Jian,Zhang, Ju,Zhu, Dajian,Li, Tao
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- Palladium(II) Complexes with Small N-Heterocyclic Carbene Ligands as Highly Active Catalysts for the Suzuki-Miyaura Cross-Coupling Reaction
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Four new palladium(II) complexes of the type [Pd(NHC)2X2] with N-heterocyclic carbene (NHC) ligands of relatively small steric hindrance were prepared and characterized by using spectroscopic and X-ray methods. For [Pd(bmim-y)2Br2] (bmim-y=1-butyl-3-methylimidazol-2-ylidene), crystals of both cis and trans isomers were obtained. All the studied complexes demonstrated very high activity in Suzuki-Miyaura cross-coupling in ethylene glycol, which yielded turnover numbers of up to 760000. High activity was also observed if NaBPh4 was used instead of PhB(OH)2, and the best results (turnover number=580000) were obtained with [Pd(emim-y)2Cl2] (emim-y=1-ethyl-3-methylimidazol-2-ylidene). In the reaction mixture, different forms containing [Pdx(NHC)y]+ fragments (x=1-4, y=2-5) were identified by using ESI-MS. In the presence of Suzuki-Miyaura reaction substrates, catalytic palladium intermediates with aryl groups-[Pd(NHC)2Ph]+ and [Pd3(NHC)4Ph]+-were detected. Additional mechanistic investigations, such as TEM observations and mercury poisoning experiments, substantiated the formation of nanoparticles as a catalyst resting state. These heterogeneous particles serve as a reservoir for soluble palladium species-atoms or clusters that function as homogeneous catalysts for the Suzuki-Miyaura reaction.
- Szulmanowicz, Michal S.,Gniewek, Andrzej,Gil, Wojciech,Trzeciak, Anna M.
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- In situ prepared mesoporous silica nanosphere supported palladium(ii) 2-aminopyridine complex catalyst for Suzuki-Miyaura cross-coupling reaction in water
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We report the synthesis and catalytic activities of a mesoporous silica nanosphere supported palladiumII 2-aminopyridine complex (Pd-AMP-MSN). First, chloroalkyl functionalized mesoporous silica nanospheres (Cl-MSN) is prepared by an in situ co-condensation reaction of tetraethyl orthosilicate (TEOS) with ((chloromethyl)phenylethyl)trimethoxysilane (CMPE-TMS) using cetyltrimethylammonium bromide (CTAB) as the structure directing agent. The reaction of Cl-MSN with 2-aminopyridine followed by complexation with palladium acetate produces the catalyst Pd-AMP-MSN. FTIR spectroscopic analysis confirms the presence of 2-aminopyridine functionality inside the mesopores of the Pd-AMP-MSN. Nitrogen adsorption-desorption and X-ray diffraction analyses reveal mesoporous structures of the Pd-AMP-MSN catalyst with a specific surface area of 372 m2 g-1, a pore volume of 0.172 cm3 g-1 and a narrow pore size distribution (D ～ 1.92 nm). FESEM and HRTEM results indeed show the formation of nanospheres with mesoporous structures. This catalytic system exhibits excellent activity in Suzuki-Miyaura cross-coupling reactions of aryl iodides, aryl bromides and also aryl chlorides with phenylboronic acids in water medium with high yields. This Pd-AMP-MSN catalyst could be quantitatively recovered by simple filtration and is found to be highly active without any significant loss of its catalytic activity in eight consecutive runs.
- Mondal, Paramita,Banerjee, Sanjib,Roy, Anupam Singha,Mandal, Tarun K.,Islam
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- Controlled synthesis of nickel(ii) dihalides bearing two different or identical N-heterocyclic carbene ligands and the influence of carbene ligands on their structures and catalysis
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Ni(ii) dihalides bearing two different or identical NHC ligands have been prepared via a controlled indene elimination synthesis, and the former product provides a new route for the design of biscarbene Ni(ii)-based catalysts. The indene elimination reaction of the indenynickel(ii) complex (1-H-Ind)Ni(NHC)X (Ind = indenyl) with one equiv. of a distinct imidazolium salt at 100 °C afforded the first example of Ni(ii) dihalides bearing two different NHC ligands, i.e., Ni(iPr)(IPr)X2 [iPr = 1,3-diisopropylimidazol-2- ylidene, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), X = Cl, 1; X = Br, 2] and Ni(iPr)(IMes)Br2 [IMes = 1,3-bis(mesityl)imidazol-2- ylidene, 3]. Alternatively, complexes 1-3 can be synthesized using a bis-indenyl Ni(ii) complex (1-H-Ind)2Ni as starting materials via a step-by-step indene elimination at different reaction temperatures. The direct reaction of (1-R-Ind)2Ni (R = H or Me) with two equiv. of imidazolium salts at 100 °C afforded Ni(ii) dihalides bearing two identical NHC ligands, i.e., Ni(iPr)X2 (X = Cl, 4; X = Br, 5) and Ni(IPr)Cl2 (6). All of these complexes were characterized by elemental analysis, NMR spectroscopy and X-ray crystallography for complexes 1-5. The two identical or different NHC ligands in complexes 1-6 changed the coordination sphere of the nickel center from a typical square-planar geometry to a slightly tetrahedral array. A preliminary catalytic study on the cross-coupling reactions of aryl Grignard reagents with aryl halides revealed that complexes 1 and 2 possess the highest activity. In comparison, complexes 3 and 6 exhibited moderate activity and the least active complexes were 4 and 5.
- Liu, Zhi-Hong,Xu, Yan-Chao,Xie, Ling-Zhi,Sun, Hong-Mei,Shen, Qi,Zhang, Yong
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- Activation of Aryl Chlorides for Suzuki Cross-Coupling by Ligandless, Heterogeneous Palladium
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matrix presented We demonstrate that Pd/C without added ligands catalyzes the Suzuki cross-coupling reaction with aryl chlorides. The ability of heterogeneous Pd to activate the C-Cl bond is explained in terms of a synergistic anchimeric and electronic effect that occurs between the Pd surface and the aryl chloride. Furthermore, the importance of selectivity control following C-Cl bond activation is illustrated by the striking role that solvents play in determining homo- vs cross-coupling pathways of the aryl chlorides.
- LeBlond, Carl R.,Andrews, Arthur T.,Sun, Yongkui,Sowa Jr., John R.
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- Highly active Pd nanoparticles dispersed on amine functionalized layered double hydroxide for Suzuki coupling reaction
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The synthesis of well dispersed palladium nanoparticles (1-5 nm) on diamine functionalized LDH is reported. The heterogeneous catalyst displayed unprecedented activity in Suzuki coupling reaction.
- Singha, Sudarshan,Sahoo, Mitarani,Parida
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- Suzuki-Miyaura reaction in water, conducted by employing an amphiphilic dendritic phosphine-palladium catalyst: a positive dendritic effect on chemical yield
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A series of amphiphilic dendritic ligands with a phosphine core was synthesized by use of tris(4-hydroxyphenyl)phosphine oxide and poly(benzyl ether) dendron. The corresponding phosphine-palladium core dendrimers were applied as a catalyst to an aqueous-media Suzuki-Miyaura reaction. A positive dendritic effect on chemical yields of cross-coupling products was observed.
- Hattori, Hatsuhiko,Fujita, Ken-ichi,Muraki, Takahito,Sakaba, Ai
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- Mechanistic and asymmetric investigations of the Au-catalysed cross-coupling between aryldiazonium salts and arylboronic acids using (P,N) gold complexes
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In order to explore the different mechanisms possibly occurring in the Au-catalysed cross-coupling of ArN2BF4 and ArB(OH)2 in the presence of CsF, various stoichiometric experiments were performed on gold complexes with (P,N) ligands. Employing 2-pyridylphenyl-diphenylphosphine allowed us to suggest three different mechanistic pathways, starting either with a transmetallation step, via two consecutive single electron transfers, or by implying a transmetallation between Au(i) and Au(iii) species. Moreover, when using commercially available chiral (P,N) ligands, the asymmetric formation of atropoisomeric biaryls from suitable aryldiazonium salts and arylboronic acids could be achieved with e.e. up to 26%.
- Tabey, Alexis,Berlande, Murielle,Hermange, Philippe,Fouquet, Eric
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- Chelate Palladium(II) Complexes with Saturated N-Phosphanyl-N-Heterocyclic Carbene Ligands: Synthesis and Catalysis
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N-Phosphanyl-N-heterocyclic carbenes (NHCPs) featuring a saturated imidazolin-2-ylidene or tetrahydropyrimid-2-ylidene ring have been synthesized and characterized. The free carbenes exhibit good stability and can be stored in the solid state for months at ambient temperature without decomposition. Contrary to imidazoline-based NHCPs, which decompose by ring opening, N-phosphanyltetrahydropyrimid-2-ylidenes isomerize to 2-phosphanyl tetrahydropyrimidines upon heating. The free carbenes are capable of acting as chelating ligands toward palladium(II), forming very stable mononuclear complexes that have been structurally characterized. The catalytic potential of the complexes has been preliminarily assessed in cross-coupling reactions, most notably in the Suzuki coupling of aryl chlorides, where these complexes display promising activity, and in the copper- and amine-free Sonogashira coupling of aryl bromides.
- Marchenko, Anatoliy,Koidan, Georgyi,Hurieva, Anastasiia N.,Vlasenko, Yurii,Kostyuk, Aleksandr,Biffis, Andrea
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- N,N-Bis(2-hydroxyethyl)-2-Aminoethanesulfonic Acid-Assisted Liquid-phase Growth of Au@Pd coreshell nanoparticles with high catalytic activity
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Au@Pd coreshell nanoparticles were successfully synthesized via sequential reduction of Au(III) and Pd(II) ions with N,N-bis(2-hydroxyethyl)-2-Aminoethanesulfonic acid (BES) at room temperature. Their size and morphology could be changed by varying the BES concentration and pH value of the reaction system. The Au@Pd coreshell nanoparticles exhibited significantly higher catalytic activity for various Suzuki reactions than monometallic Pd or Au nanoparticles. The size-dependent catalytic activity was also observed, i.e., the Au@Pd coreshell nanoparticles of 10nm showed higher activity.
- Zhang, Wei,Zhao, Huiping,Lu, Zhong,Chen, Fengxi,Chen, Rong
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- Water-soluble metal nanoparticles with PEG-tagged 15-membered azamacrocycles as stabilizers
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The synthesis of palladium, platinum and ruthenium nanoparticles stabilized by azamacrocycles bearing polyoxyethylenated chains has been achieved by decomposition of the corresponding organometallic precursors (Pd(dba) 2, Pt2(dba)3 and Ru(COD)(COT)) under dihydrogen atmosphere, whereas gold and rhodium nanoparticles have been obtained in the presence of these ligands by reduction of HAuCl4 and RhCl 3, respectively. The metal nanoparticles were characterized by several techniques including IR, NMR, UV-vis, HRTEM, ED, and elemental analysis. The Pd nanoparticles have been used as recoverable catalyst in Suzuki cross-coupling in aqueous medium.
- Mejias, Nereida,Serra-Muns, Anna,Pleixats, Roser,Shafir, Alexandr,Tristany, Mar
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- Hemicelluloses supported palladium/xylan nanocomposites containing N and O ligands: Highly-performance heterogeneous catalysts for Suzuki reaction
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Two kinds of xylan/palladium catalysts (PACMX-Pd and EDAX-Pd) were simply fabricated by integrating two N bidentate ligands into the skeleton of oxygen-rich xylan and followed with the in-situ reduction of palladium. The Pd loading in PACMX-Pd and EDAX-Pd nanocomposites was 0.353 mmol/g and 0.302 mmol/g, respectively. The catalysts exhibited an excellent catalytic activity for the Suzuki reaction with a yield of high up to 100% as well as a superior turnover frequency (TOF: 9626 h?1). Moreover, the catalysts showed outstanding stability and could be reused for at least 5 times without significant decrease in activity. Compared with other polymers and non-polymers supported palladium catalysts, the as-prepared biomass-based catalysts possess potential applications in a wide range of organic catalysis.
- Du, Fan,Zhang, Lei,Ma, Jiliang,Peng, Xinwen
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- One-pot solvothermal synthesis of Pd/Fe3O4 nanocomposite and its magnetically recyclable and efficient catalysis for Suzuki reactions
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A facile solvothermal synthetic route has been successfully developed to fabricate Pd/Fe3O4 nanocomposite with the assistance of polyvinylpyrrolidone (PVP) in N,N-dimethylformamide (DMF) solution. The as-prepared Pd/Fe3O4 nanocomposite was composed of uniform 5 nm-sized Pd nanoparticles and Fe3O4 nanocrystals with dimension of 40 nm. In this fabrication, PVP played an important role as a capping agent. The as-prepared Pd/Fe3O4 nanocomposite exhibited superior catalytic performance and stability for various Suzuki coupling reactions, compared with single-component Pd nanoparticles under the same reaction conditions. More importantly, it displayed good magnetic property and could be easily separated from the reaction mixture by using a magnet and recycled for 10 times without losing its catalytic activity.
- Li, Shaozhong,Zhang, Wei,So, Man-Ho,Che, Chi-Ming,Wang, Runming,Chen, Rong
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- The application of organic bases in microwave-promoted Suzuki coupling reactions in water
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Traditionally, mineral bases are used in Suzuki coupling protocols. The use of DBU or DABCO as alternative bases for the reaction is reported and the application discussed.
- Chanthavong, Florine,Leadbeater, Nicholas E.
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- Palladium-coated nickel nanoclusters: New Hiyama cross-coupling catalysts
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The advantages of bimetallic nanoparticles as C-C coupling catalysts are discussed, and a simple, bottom-up synthesis method of core-shell Ni-Pd clusters is presented. This method combines electrochemical and 'wet chemical' techniques, and enables the preparation of highly monodispersed structured bimetallic nanoclusters. The double-anode electrochemical cell is described in detail. The core-shell Ni-Pd clusters were then applied as catalysts in the Hiyama cross-coupling reaction between phenyltrimethoxysilane and various haloaryls. Good product yields were obtained with a variety of iodo- and bromoaryls. We found that, for a fixed amount of Pd atoms, the core-shell clusters outperform both the monometallic Pd clusters and the alloy bimetallic Ni-Pd ones. THF is an excellent solvent for this process, with less than 2% homocoupling by-product. The roles of the stabiliser and the solvent are discussed. the Owner Societies 2006.
- Duran Pachon, Laura,Thathagar, Mehul B.,Hartl, Frantisek,Rothenberg, Gadi
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- Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acids over gold nano-particles supported on MgO (or CaO) and other metal oxides
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Gold nano-particles-supported alkaline earth metal oxides, particularly MgO or CaO, show high catalytic activity in the Suzuki-Miyaura cross-coupling reaction in the presence of K2CO3 and DMF (as a solvent). The catalytic activity is strongly influenced by the nature or type of metal oxide support (viz. alkaline earth oxide, Group IIIA metal oxide, transition metal oxide, or rare earth oxide actinide oxide). It is also strongly influenced by the nature of aryl halide (aryl iodide, bromide, chloride, or fluoride), amount of K2CO3 in the reaction mixture and catalyst calcination temperature. Influence of reaction parameters viz. temperature and time and different substituents in aryl halides and/or phenylboronic acids on the biphenyl product yield in the reaction over Au/MgO catalyst has also been investigated. The catalyst showed excellent reusability in the reaction. Moreover, it is ligand-free and also has much lower cost than the commonly used homogeneous and heterogeneous Pd catalysts.
- Dumbre,Yadav,Bhargava,Choudhary
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- Facile synthesis, characterization and application of highly active palladium nano-network structures supported on electrospun carbon nanofibers
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Palladium nano-network structures supported on electrospun carbon nanofibers (Pd-NNSs-ECNFs) were successfully prepared through a novel K2PdIICl4/K4FeII(CN)6 cyanogel method. The Pd-NNSs have the features and properties of small particle size, low dimensionality, quantum effects and high stability. SEM, TEM and XPS were used to characterize the Pd-NNSs-ECNFs. The Pd-NNSs-ECNFs were used as a catalyst in different types of Suzuki coupling reactions to evaluate the catalytic abilities. The results showed that the heterogeneous catalyst (Pd-NNSs-ECNFs) had a high catalytic activity (high yields to the products) to the Suzuki coupling reactions in an environmentally friendly solvent system (ethanol/H2O). The catalyst can be recycled by filtration, and reused seven times without losing the catalytic activity. This research opens new applications of Pd-NNSs-ECNFs in the area of green chemistry. This journal is
- Peng, Xinwen,Ye, Wan,Ding, Yichun,Jiang, Shaohua,Hanif, Muddasir,Liao, Xiaojian,Hou, Haoqing
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- Heterogeneous Suzuki and Stille coupling reactions using highly efficient palladium(0) immobilized MCM-41 catalyst
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An efficient palladium(0) immobilized MCM-41 catalytic system for C-C cross-coupling reaction has been developed. Ligand-free Pd(0)-MCM-41 catalyst can be successfully used in coupling reaction between various aryl halides including deactivated chlorobenzene with aryl borane and organotin to give biaryls in excellent yields with high turnover frequency (TOF) (the maximal TOFs are up to 6990 for the reaction of bromobenzene with phenylboronic acid). The catalyst can be recycled and reused without any loss of catalytic activity.
- Jana, Sreyashi,Haldar, Satyajit,Koner, Subratanath
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- Palladium-dodecanethiolate nanoparticles as stable and recyclable catalysts for the Suzuki-Miyaura reaction of aryl halides under ambient conditions
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Palladium-dodecanethiolate nanoparticles (PdTNs) catalyze the quantitative Suzuki-Miyaura coupling of halogenoarenes under biphasic conditions in THF/water at room temperature and can be recovered by precipitation using ethanol and re-used.
- Lu, Feng,Ruiz, Jaime,Astruc, Didier
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- Synthesis of a recyclable and efficient Pd(ii) 4-(2-pyridyl)-1,2,3-triazole complex over a solid periodic mesoporous organosilica support by "click reactions" for the Stille coupling reaction
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A highly efficient, reusable B-PMO-TZ-Pd(ii) catalyst was synthesized by anchoring 4-(2-pyridyl)-4-(2-pyridyl)-1,2,3-triazole ligand over the surface of an organo-functionalized benzene support containing periodic mesoporous organosilica (B-PMO) via "click reaction" and the subsequent complexation with PdCl2. B-PMO materials with uniform hexagonal arrangements were prepared using C16 alkyl trimethyl ammonium bromide [CTAB] surfactant under basic conditions. The physiochemical properties of the functionalised catalyst were analysed by elemental analysis, ICP-OES, XRD, N2 sorption, TGA & DTA, solid state 13C, 29Si NMR spectra, FT-IR, XPS, UV-vis, SEM and TEM. XRD and N2 sorption revealed the morphological and textural properties of the synthesized catalyst, confirming that ordered mesoporous channel structure was retained even after the multistep synthetic procedure. The (100), (110) and (200) reflections in B-PMO are evidence of its good structural stability and the existence of long range order. The TGA-DTA results reveal that the synthesized catalyst B-PMO-TZ-Pd(ii) was thermally stable, even at high temperature. The organic moieties anchored over the surface of B-PMO were demonstrated by solid state 13C NMR and FT-IR spectroscopy. Solid state 29Si NMR spectroscopy provides information about the degree of functionalization of the surface silanol group. The electronic environment and oxidation state of Pd in B-PMO-TZ-Pd(ii) were monitored by XPS and UV-visible techniques. Moreover, the morphologies and topographic information of the synthesized B-PMO-TZ-Pd(ii) catalyst were confirmed by SEM and TEM analyses. The catalytic properties of the catalyst for the Stille coupling reaction were screened, and higher catalytic activities with high TONs were observed. The anchored solid B-PMO-TZ-Pd(ii) catalyst can be recycled efficiently and reused several (four) times without a major loss in reactivity. This journal is
- Sharma, Priti,Singh
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- Evaluation of catalytic properties of aminocarbene species derived from the integration between 3-iminoisoindolin-1-ones and palladium-bound isonitriles in Suzuki-Miyaura cross-coupling
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A series of palladium aminocarbene complexes [PdCl{C(NC(C6R 2R3R4R5CON))N(H)R 1}(CNR1)] (9-23, 80-85% isolated yield) were obtained via the metal-mediated integration of one ison
- Chay, Rogerio S.,Luzyanin, Konstantin V.
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- Transition-metal-free Suzuki-type coupling reactions: Scope and limitations of the methodology
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The scope and limitations of the transition-metal-free Suzuki-type coupling of aryl halides and arylboronic acids to form biaryls are presented. Confirmation that the reaction is indeed metal-free is presented. The effects of changing base, solvent, reaction temperature, phase-transfer catalyst, and substrate are shown and the implications of these results discussed in terms of their impact on the synthetic versatility of the methodology. The main findings are that the reaction works well for aryl bromides, water is necessary as a solvent for the reaction, the optimum temperature for the reaction is 150 °C, the reaction is best performed by using microwave promotion with the exception of an electron-poor aryl bromide example where conventional heating may be used, only limited boronic acids can be used as coupling partners, sodium carbonate is the best base for the reaction, tetrabutylammonium bromide proves to be the best phase-transfer catalyst for the reaction, the reaction is limited to couplings between aryl halides and aryl boronic acids with sp2-sp3 couplings proving ineffective, and NaBPh4 can be used in the place of phenylboronic acid as a phenylating agent.
- Leadbeater, Nicholas E.,Marco, Maria
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- Highly active, air-stable palladium catalysts for Kumada-Tamao-Corriu cross-coupling reaction of inactivated aryl chlorides with aryl Grignard reagents
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Palladium (II) chlorides possessing phosphinous acid ligands have proved to be remarkably active and efficient catalysts for cross-coupling reactions of inactivated aryl chlorides with aryl Grignard reagents (Kumada-Tamao-Corriu reaction) at room temperat
- Li, George Y
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- Three-coordinate nickel(i) complexes stabilised by six-, seven- and eight-membered ring N-heterocyclic carbenes: Synthesis, EPR/DFT studies and catalytic activity
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Comproportionation of [Ni(cod)2] (cod=cyclooctadiene) and [Ni(PPh3)2X2] (X=Br, Cl) in the presence of six-, seven- and eight-membered ring N-aryl-substituted heterocyclic carbenes (NHCs) provides a route to a series of isostructural three-coordinate Ni I complexes [Ni(NHC)(PPh3)X] (X=Br, Cl; NHC=6-Mes 1, 6-Anis 2, 6-AnisMes 3, 7-o-Tol 4, 8-Mes 5, 8-o-Tol 6, O-8-o-Tol 7). Continuous wave (CW) and pulsed EPR measurements on 1, 4, 5, 6 and 7 reveal that the spin Hamiltonian parameters are particularly sensitive to changes in NHC ring size, N substituents and halide. In combination with DFT calculations, a mixed SOMO of |3dz2〉 and |3dx2 - y2〉 character, which was found to be dependent on the complex geometry, was observed and this was compared to the experimental g values obtained from the EPR spectra. A pronounced 31P superhyperfine coupling to the PPh3 group was also identified, consistent with the large spin density on the phosphorus, along with partially resolved bromine couplings. The use of 1, 4, 5 and 6 as pre-catalysts for the Kumada coupling of aryl chlorides and fluorides with ArMgY (Ar=Ph, Mes) showed the highest activity for the smaller ring systems and/or smaller substituents (i.e., 1>4≈6?5). Copyright
- Page, Michael J.,Lu, Wei Y.,Poulten, Rebecca C.,Carter, Emma,Algarra, Andres G.,Kariuki, Benson M.,MacGregor, Stuart A.,Mahon, Mary F.,Cavell, Kingsley J.,Murphy, Damien M.,Whittlesey, Michael K.
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- Efficient click-polymer-stabilized palladium nanoparticle catalysts for Suzuki-Miyaura reactions of bromoarenes and reduction of 4-nitrophenol in aqueous solvents
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Palladium nanoparticles (size=1.6 ± 0.3 nm) stabilized by a polyethylene glycol containing triazolyl rings, synthesized by click reaction in water, are efficient catalysts for the Suzuki-Miyaura coupling of bromoarenes in aqueous ethanol and the borohydride reduction of 4-nitrophenol in water. Turnover numbers (TONs) reach 99,000 and turnover frequencies (TOFs) are up to 198,000 h-1 for the C-C cross coupling reactions in water/ethanol.
- Deraedt, Christophe,Salmon, Lionel,Ruiz, Jaime,Astruc, Didier
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- Suzuki-Miyaura reaction catalyzed by a dendritic phosphine-palladium complex
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We prepared several of a new type of a dendritic ligand with a phosphine core by using tris(4-hydroxyphenyl)phosphine oxide and poly(aryl ether) dendron. In particular, when an amphiphilic dendritic phosphine-palladium complex was used as a catalyst, the aqueous media Suzuki-Miyaura reaction proceeded smoothly to provide the corresponding cross-coupling product at 50 °C. A positive dendritic effect on chemical yields was observed.
- Fujita, Ken-Ichi,Hattori, Hatsuhiko
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- A novel P,O-type phosphorinane ligand for the Suzuki-Miyaura cross-coupling of aryl chlorides
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The Pd-mediated Suzuki-Miyaura cross-coupling of substituted and unsubstituted aryl chlorides with phosphorinane ligands was investigated uncovering an interesting ligand effect. The scope of the most effective 4-hydroxyl-substituted phosphorinane ligand in Suzuki cross-coupling with challenging aryl chlorides is described.
- Ullah, Ehsan,McNulty, James,Robertson, Al
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- Disubstituted benzenes from acyclic precursors by a [5+1] annulation
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Horner-Wadsworth-Emmons reaction of stannylvinylphosphonates with aldehydes and mild thermal cyclisation provides disubstituted arylstannanes. Subsequent Stille coupling leads to regiospecific synthesis of m- and p-terphenyls. Georg Thieme Verlag Stuttgar
- Daniels, David S. B.,Brown, John M.,Gayral, Maud,Xu, Yingjian,Stewart, Malcolm I.
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- Microwave-assisted facile synthesis of palladium nanoparticles in HEPES solution and their size-dependent catalytic activities to Suzuki reaction
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Palladium nanoparticles (NPs) were successfully synthesized via a rapid and facile microwave route in HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid) buffer solution. The shape- and size-controlled Pd nanoparticles could be obtained by one-step method without dependence of seed-mediated growth. The capping agent plays a key role in the formation of Pd NPs with different shape and size, which could be tuned by varying capping agents such as polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), sodium citrate (Na3(cit)) and potassium bromide (KBr). The size-dependent catalytic activities of the obtained Pd NPs for Suzuki coupling reaction were also investigated. It demonstrated that the catalytic activity of Pd NPs was enhanced regularly with the decrease of particle size. Pd NPs less than 10 nm exhibited better catalytic activities for Suzuki reaction than the commercial Pd/C catalyst. Pd/MWCNTs and Pd/SBA-15 nanocomposites were also prepared by a facile method and afforded good catalytic activity and reusability. This "green" synthetic protocol could be used as a general method for the rapid synthesis of transition metal nanoparticles. Copyright
- Zhang, Wei,Wang, Qiao,Qin, Fan,Zhou, Huamin,Lu, Zhong,Chen, Rong
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- Palladium-catalysed Grignard cross-coupling using highly concentrated Grignards in methyl-tetrahydrofuran
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The cross-coupling of Grignard reagents at 5 molar concentration in methyl-tetrahydrofuran with no added reaction solvents can be achieved with the appropriate matching of catalyst to substrate, significantly reducing solvent use when compared to a typical protocol in tetrahydrofuran. Me-THF was also used in an improved microwave accelerated synthesis of the [Pd(L)Cl2] pre-catalysts from sodium tetrachloropalladate in very high yield.
- Milton, Edward J.,Clarke, Matthew L.
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- Supramolecular reactor in an aqueous environment: Aromatic cross Suzuki coupling reaction at room temperature
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We have investigated supramolecular reactors for the Suzuki coupling reactions of aryl halides with phenyl boronic acids by using self-assembly of amphiphilic rod-coil molecules in aqueous solution at room temperature. All the rod-coil molecules synthesized in this work showed to self-assemble into discrete micelles consisting of aromatic rod bundles encapsulated by hydrophilic poly-(ethylene oxide) coils. We present a comparative study of rod-coil molecules' efficiency as supramolecular reactors for Suzuki coupling reaction. The closed-packed aromatic bundles play an efficient role in supramolecular reactors for the coupling reactions at room temperature. The supramolecular reactor based on hexa-p-phenylene confers unprecedented activity, allowing reactions to be performed at very low catalyst levels, without conventional heating or microwave.
- Ryu, Ja-Hyoung,Jang, Cheong-Jin,Yoo, Yong-Sik,Lim, Sung-Gon,Lee, Myongsoo
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- Combining N-heterocyclic carbenes and phosphines: Improved palladium(II) catalysts for aryl coupling reactions
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Complexes of the type (NHC)Pd(PR3)I2 with bulky N-heterocyclic carbenes (NHC) are efficient catalysts for aryl coupling reactions such as the Suzuki and Stille cross-coupling reaction. These catalysts combine the advantageous stability of bis(carbene) complexes and the good activity of the bis(phosphine) complexes in these reactions. Both arylbromides and arylchlorides can be used as substrates.
- Weskamp, Thomas,Boehm, Volker P.W.,Herrmann, Wolfgang A.
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- Heteropolymetallic complexes linked to a 9,10-dihydroanthracenyl frame. Ruthenium as active spectator for palladium reactivity
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New monometallic Pd(II) (3, 4) and heteropolymetallic Pd(II)/Ru(II) complexes (5, 6) linked to an original 9,10-dihydroanthracenyl-pyrrolidine scaffold were synthesized and fully characterized. For monometallic complexes, exo-3 and endo-4 conformers were exclusively obtained from Pd(OAc)2 and [PdCl2(COD)], respectively. The formation of the sterically hindered endo-4 was justified by the positive noncovalent intramolecular Cl-π interaction, observed by X-ray diffraction. The reaction of endo-4 with 1 and 2 equiv of [RuCp(NCMe)3]PF6 led to complexes 5 and 6, respectively. It is worth noting that lower conversions in the Suzuki-Miyaura coupling were found using 5 and 6 as catalysts, in comparison to those with monometallic palladium complexes. This behavior could be related to the higher stabilization of Pd(II) species for the heteropolymetallic complexes, as proven by electrochemical analyses.
- Bratko, Ielyzaveta,Mallet-Ladeira, Sonia,Teuma, Emmanuelle,Gomez, Montserrat
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- A highly controllable, effective, and recyclable magnetic-nanoparticle-supported palladium catalyst for the Suzuki–Miyaura cross-coupling reaction
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In this work, a highly efficient palladium catalyst was facilely immobilized on the surfaces of magnetic nanoparticles with the coordination of N-heterocyclic carbene. The prepared Pd–NHC@NCPs were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectrometry. With suitably designed emulsion polymerization and immobilization, the final palladium loading could reach 0.78 mmol/g. The catalyst showed outstanding catalytic performance in the Suzuki–Miyaura cross-coupling reaction among various substrates, with little catalyst usage (0.03 mol.%), short reaction time, and mild reaction conditions. In addition, the catalyst could be separated conveniently from the reacting system with an external magnet and show good catalytic performance even after being reused five times or more, indicating good recyclability.
- Ye, Lu,Liu, Xiaojing,Lu, Yangcheng
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- Revisiting Claims of the Iron-, Cobalt-, Nickel-, and Copper-Catalyzed Suzuki Biaryl Cross-Coupling of Aryl Halides with Aryl Boronic Acids
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Intrigued by recent reports on the surprisingly excellent activity of a range of cobalt-, iron-, copper-, and nickel-based catalysts in the Suzuki biaryl cross-coupling of simple aryl boronic acids with aryl halides, we undertook a reexamination of the syntheses of representative examples of the reported precatalysts and their application to the catalytic reaction. A reported PNP-Fe pincer complex proved to be a mixture of starting materials; a mono-Schiff base cobalt complex in fact the bis-ligated adduct and a monomeric copper(II) PNP-pincer complex a di- or oligomeric copper(I) species. In our hands, neither these complexes nor any other of the selected precatalysts investigated showed any activity in a Suzuki cross-coupling reaction of an electronically activated aryl bromide with phenyl boronic acid. Meanwhile, switching the nucleophile to the BuLi-activated phenyl boronic pinacol ester gave some promising activity with cobalt precatalysts.
- Tailor, Sanita B.,Manzotti, Mattia,Asghar, Soneela,Rowsell, Benjamin J. S.,Luckham, Stephen L. J.,Sparkes, Hazel A.,Bedford, Robin B.
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- Fluorine-substituted arylphosphine for an NHC-Ni(I) system, air-stable in a solid state but catalytically active in solution
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Monovalent NHC-nickel complexes bearing triarylphosphine, in which fluorine is incorporated onto the aryl groups, have been synthesized. Tris(3,5-di(trifluoromethyl)phenyl)phosphine efficiently gave a monovalent nickel bromide complex, whose structure was determined by X-ray diffraction analysis for the first time. In the solid state, the Ni(I) complex was less susceptible to oxidation in air than the triphenylphosphine complex, indicating greatly improved solid-state stability. In contrast, the Ni(I) complex in solution can easily liberate the phosphine, high catalytic activity toward the Kumada–Tamao–Corriu coupling of aryl bromides.
- Matsubara, Kouki,Fujii, Takahiro,Hosokawa, Rion,Inatomi, Takahiro,Yamada, Yuji,Koga, Yuji
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- Carboxyl-containing microporous organic nanotube networks as a platform for Pd catalysts
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In this work, we present a novel synthesis of carboxyl-containing microporous organic nanotube networks (COOH-MONNs) by combination of hyper-cross-linking and molecular templating of core-shell bottlebrush copolymers. Highly dispersed palladium nanoparticles (Pd NPs) anchored on the COOH-MONNs (Pd@MONNs) have been prepared by in situ thermal decomposition of Pd(OAc)2. The Pd@MONNs composites were characterized by XRD, N2 adsorption, TEM, ICP-AES and XPS. The results show that bulk production of highly dispersed palladium nanoparticles can be achieved by a thermal decomposition method. Moreover, the obtained Pd@MONNs exhibit high activities for the Suzuki-Miyaura cross-coupling reaction and can be easily recovered and reused. This approach of using MONNs as a platform for catalysts is expected to open doors for new types of catalytic support for practical applications.
- Xu, Yang,Wang, Tianqi,He, Zidong,Zhong, Aiqing,Huang, Kun
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- Fe3O4 nanoparticles-supported palladium-bipyridine complex: Effective catalyst for suzuki coupling reaction
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Fe3O4 nanoparticles-supported palladium-2, 2-bipyridine complex was synthesized and used as catalyst for Suzuki coupling reactions between different aryl iodides and bromides with phenyl boronic acid under mild conditions. This catalyst can be separated magnetically. However, due to the aggregation of catalyst with the increase in reaction times, the activity dropped dramatically from >99% for the first time use to 45% for the fourth time use and then kept constant subsequently.
- Zhang, Yan-Qi,Wei, Xian-Wen,Yu, Rui
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- Recyclable palladium-graphene nanocomposite catalysts containing ionic polymers: efficient Suzuki coupling reactions
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Palladium nanoparticles on ionic polymer-doped graphene (Pd-IPG) nanocomposite catalysts have been investigated for efficient Suzuki coupling reactions. This combination effected highly accelerated Suzuki coupling reactions due to several advantageous features associated with the flanking ionic polymer part of the catalyst system. These include a high level of Pd incorporation, excellent dispersion stability, and increased accessibility and diffusion of the substrates onto the surface of Pd NPs. The enhanced availability of the Pd catalyst to the reacting substrates is believed to allow for ca. 16-fold higher catalytic activity than that of Pd-graphene without the ionic polymer. Moreover, high recycling capability of the catalyst (10 times) in combination with excellent product yields (>96%) and no significant leaching of the catalyst upon hot-filtration test suggest that the Pd-IPG nanocomposite catalysts have high reusability with significant retention (>95%) of the Pd species.
- Kwon, Tae Hui,Cho, Kie Yong,Baek, Kyung-Youl,Yoon, Ho Gyu,Kim, B. Moon
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- Palladium Immobilized on a Polyimide Covalent Organic Framework: An Efficient and Recyclable Heterogeneous Catalyst for the Suzuki–Miyaura Coupling Reaction and Nitroarene Reduction in Water
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An efficient and recyclable Pd nano-catalyst was developed via immobilization of Pd nanoparticles on polyimide linked covalent organic frameworks (PCOFs) that was facilely prepared through condensation of melamine and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. The Pd nanoparticles (Pd NPs) catalyst was thoroughly characterized by FT-IR, XRD, SEM, TEM. Furthermore, the catalytic activity of Pd NPs catalyst was evaluated by Suzuki–Miyaura coupling reaction and nitroarene reduction in water, respectively. The excellent yields of corresponding products revealing revealed that the Pd NPs catalyst could be applied as an efficient and reusable heterogeneous catalyst for above two reactions. Graphical Abstract: [Figure not available: see fulltext.]
- Dong, Zhenhua,Pan, Hongguo,Gao, Pengwei,Xiao, Yongmei,Fan, Lulu,Chen, Jing,Wang, Wentao
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p. 299 - 306
(2021/05/10)
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- An environment-friendly dip-catalyst with xylan-based catalytic paper coatings
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Replacing catalyst supports with sustainable and degradable materials is an urgent task. Xylan is a type of abundant natural polymers with potential applications in dispersing, anchoring, and coating materials, but its material values have always been underestimated. In this study, polyethyleneimine modified dialdehyde xylan (DAX-PEI) was used as a dispersing and anchoring agent to bind Pd nanoparticles onto paper surface to produce a DAX-PEI-Pd coated paper, which was used to catalyze Suzuki-Miyaura reactions. The catalytic coated paper exhibited a good catalytic activity with a yield of 91% and a high turnover frequency (TOF) of 3300 h?1. Besides, it showed an excellent recyclability with the same catalytic coated paper being used 15 times and still having a yield of nearly 90%. This environment-friendly catalytic coated paper owns its great prospect in organic synthesis.
- He, Mengyun,Song, Tao,Qi, Haisong,Xiang, Zhouyang
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- An Imidazole-Rich Pd(II)-Polymer Pre-catalyst for the Suzuki-Miyaura Coupling: Stability Influenced by Dissolved Oxygen and Reactants Concentration
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Herein a novel Pd(II)-polymeric pre-catalyst was prepared by coordinating Pd(II) ions to a low cost imidazole/carboxylate-rich polymer. The material displays good activity in the Suzuki-Miyaura coupling towards a range of aryl bromides and iodides in iPrOH/H2O mixtures at 25 or 60 °C. Catalyst longevity and recyclability proved to be sensitive to the concentration of the cross-coupling partners. When the concentration of PhBr is high ([PhBr]=250 mmol L?1), inactive Pd(0) aggregates were detected. On the other hand, when the reaction was performed at 20-fold dilution ([PhBr]=12.5 mmol L?1) the material could be reused up to 12 times without significant loss of catalytic activity. In this condition, minimum amount of Pd(0) was detected by XPS analysis and no Pd(0) aggregates were observed by XRPD. Importantly, it was found that the presence of oxygen is fundamental for avoiding formation of inactive Pd(0) aggregates.
- Nishida, Elvis N.,Leopoldino, Elder C.,Zaramello, Laíze,Centurion, Higor A.,Gon?alves, Renato V.,Affeldt, Ricardo F.,Campos, Carlos E. M.,Souza, Bruno S.
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- Carbohydrate-substituted N-heterocyclic carbenes Palladium complexes: High efficiency catalysts for aqueous Suzuki–Miyaura reaction
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Metal complexes that contain carbohydrate-substituent (Carb-) N-heterocyclic carbenes (NHCs) ligand have demonstrated great success as catalysts for organic synthesis reactions. In this study, four new Carb-NHC-Pd complexes 2a-d were prepared and their catalytic activities for Suzuki–Miyaura reaction were evaluated. The Carb-NHC-Pd complex behaved as a general surfactant which leads to the formation of a temporary oil-in-water contact interface, thereby promoting the Suzuki–Miyaura reaction. A long hydrophobic alkyl chain (–nC16H33) was remotely linked to complex 2d, in which Carb-NHCs showed high electron-donating properties, and steric bulk with 1JCH constant of 1H NMR. Complex 2d exhibited a higher catalytic activity as compared with 2a (–nC2H5), 2b (–nC4H9), and 2c (–nC8H17). A series of fluorene-cored materials with different aryl groups were synthesized with high yields (34 examples, 91–99%) under the optimized reaction conditions.
- Hu, Yunchi,Huang, Qing,Huang, Yanxia,Li, Jing,Wen, Xiaoming,Xie, Qian,Xie, Yongrong,Xu, Guohai,Zhou, Zhonggao
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supporting information
(2022/02/10)
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- Organocatalytic synthesis of (Het)biaryl scaffoldsviaphotoinduced intra/intermolecular C(sp2)-H arylation by 2-pyridone derivatives
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A uniqueN,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcasedviathe construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
- Das, Tapas Kumar,Kundu, Mrinalkanti,Mondal, Biswajit,Ghosh, Prasanjit,Das, Sajal
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p. 208 - 218
(2021/12/29)
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- Suzuki-Miyaura Cross-Coupling Reaction with Potassium Aryltrifluoroborate in Pure Water Using Recyclable Nanoparticle Catalyst
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This paper describes the Suzuki Miyaura cross-coupling reaction of aryl bromides with potassium aryltrifluoroborates in water catalyzed by linear polystyrene-stabilized PdO nanoparticles (PSPdONPs). The reaction of aryl bromides having electron-withdrawing groups or electron-donating groups took place smoothly to give the corresponding coupling product in high yields. The catalyst recycles five times without significant loss of catalytic activity although a little bit increase in size of PdNPs was observed after the reaction.
- Kawase, Misa,Matsuoka, Kyosuke,Shinagawa, Tsutomu,Hamasaka, Go,Uozumi, Yasuhiro,Shimomura, Osamu,Ohtaka, Atsushi
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- Nickel-Catalyzed Direct Cross-Coupling of Aryl Sulfonium Salt with Aryl Bromide
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The direct cross-couplings of aryl sulfonium salts with aryl halides could be achieved by using nickel as a reaction catalyst. The reactions proceeded efficiently via C-S bond activation in the presence of magnesium turnings and lithium chloride in THF at ambient temperature to afford the corresponding biaryls in moderate to good yields, potentially serving as an attractive alternative to conventional cross-coupling reactions employing preprepared organometallic reagents.
- Ma, Na-Na,Ren, Jing-Ao,Liu, Xiang,Chu, Xue-Qiang,Rao, Weidong,Shen, Zhi-Liang
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p. 1953 - 1957
(2022/03/27)
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- Biaryl Coupling of Aryldiazonium Salts and Arylboronic Acids Catalysed by Gold
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A gold-catalysed coupling of aryldiazonium salts with arylboronic acids is described. The reactions proceed in satisfactory yields under irradiation with blue LEDs in the presence of KF and a catalytic amount of ascorbic acid. Notably, 4-nitrobenzendiazonium tetrafluoroborate is sufficiently reactive to undergo the coupling with a variety of arylboronic acids in the absence of aryl radical initiators. The coupling is applicable for electron-donating and electron-withdrawing groups present at the para, ortho, and meta positions of both substrates.
- Medina-Mercado, Ignacio,Porcel, Susana
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- Palladium-catalyzed aryl group transfer from triarylphosphines to arylboronic acids
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A study of Pd-catalyzed arylation of arylboronic acids with triarylphosphines is presented. Various parameters of this transformation, such as the oxygen presence, choice of solvent, temperature, palladium source, bases and oxidants, were tested and the optimal conditions of the aryl transfer were determined. The effect of electron-withdrawing and electron-donating substituents on the aryl groups of both reactants was also investigated. The unusual transfer of the acetate group from Pd(OAc)2 to p-nitrophenylboronic acid in the presence of PAr3 is reported. A plausible mechanism of the Pd-catalyzed aryl group transfer from PAr3 to the arylboronic acid is proposed.
- Enright, Dale R.,Gogate, Akash R.,Smoliakova, Irina P.,Vasireddy, Purna C. R.
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- Silk?Fibroin-Supported Palladium Catalyst for Suzuki-Miyaura and Ullmann Coupling Reactions of Aryl Chlorides
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Recently, we have reported the preparation of a silk fibroin-supported Palladium catalyst (Pd/SF) and its use in the Suzuki-Miyaura cross-coupling of aryl iodides. Since its synthetic applicability and structural features are still far from being fully ex
- Albano, Gianluigi,Farinola, Gianluca M.,Giannini, Cinzia,Musio, Roberta,Omenetto, Fiorenzo G.,Rizzo, Giorgio,Sibillano, Teresa
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- 'Awaken' aryl sulfonyl fluoride: a new partner in the Suzuki-Miyaura coupling reaction
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An example of the activation of the -SO2F group, which is traditionally considered a stable group even in the presence of a transition metal, is described using a novel partner in the Suzuki-Miyaura coupling reaction catalyzed by Pd(OAc)2 and Ruphos as ligands. The products showed good to outstanding yields and broad functional group compatibility under optimal conditions. The sequential synthesis of non-symmetric terphenyls and the gram grade process highlight the approach's synthetic utility. DFT calculations have shown that Pd0 prefers to insert between C-S bonds rather than S-F bonds. This journal is
- Ding, Chengrong,Guan, Chenfei,Miao, Huihui,Zhang, Guofu,Zhao, Yiyong
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supporting information
p. 3560 - 3564
(2022/03/07)
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- Porous Organic Phenanthroline-Based Polymer as an Efficient Transition-Metal-Free Heterogeneous Catalyst for Direct Aromatic C?H Activation
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Direct C?H bond transformation has been regarded as one of the most important areas in organic synthesis in both academia and industry. However, the heterogeneous transition-metal-free catalysis of direct C?H bond transformation has remained a contemporary challenge. To tackle this challenge, we designed and constructed a porous phenanthroline-based polymer (namely POP-Phen) via free radical polymerization of vinyl-functionalized phenanthroline monomers. POP-Phen shows excellent catalytic performances in transition-metal-free catalyzed C?H arylation, even better than those of the corresponding homogeneous catalyst, which is mainly attributed to the high density of catalytically active sites in the heterogeneous catalyst. Kinetic isotope experiments and spectral characterizations demonstrate the electron-transfer between the heterogeneous catalyst and the base (t-BuOK), a key step for C?H activation. We believe that this porous organic phenanthroline polymer could open a new door for the design of novel heterogeneous transition-metal-free catalysts for direct C?H activation.
- Tang, Yongquan,Chen, Fang,Wang, Sai,Sun, Qi,Meng, Xiangju,Xiao, Feng-Shou
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supporting information
p. 8684 - 8688
(2021/05/25)
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- Anchored Pd(0) Nanoparticles on Synthetic Talc for the Synthesis of Biaryls and a Precursor of Angiotensin II Inhibitors
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The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction is one of the most important and efficient reactions to prepare a variety of organic compounds, including biaryls. Despite the overwhelming number of reports related to this topic, some methodological difficulties persist in terms of catalyst handling, recovery, and reuse, as well as the reaction media. This work reports the rational design of new, efficient, cost-effective, and reusable palladium catalysts supported on synthetic talc for the Suzuki-Miyaura reaction. From the results, key points were identified: both designed catalysts accelerated the reaction in EtOH and an open-flask setup, affording moderate to excellent yields within a short time (e.g., 30 min) even for deactivated aryl halides; the protocol can be applied to a great number of both cross-coupling partners, showing an excellent functional group tolerance; the catalysts can be recovered and reused without significant loss of activity. This protocol was used for the synthesis of a precursor of angiotensin II inhibitors such as valsartan, losartan, irbesartan, and telmisartan.
- Dos Santos, Beatriz F.,Da Silva, Beatriz A. L.,De Oliveira, Aline R.,Sarragiotto, Maria H.,Domingues, Nelson Luís C.
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p. 933 - 942
(2020/12/28)
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- Fe3O4-SAHPG-Pd0 nanoparticles: A ligand-free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C-H activation of pyrimidine cores
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This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd0 nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe3O4 nanoparticles (Fe3O4-SAHPG-Pd0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of PdII to Pd0 nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)2 was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.
- Azizollahi, Hamid,Eshghi, Hossein,García-López, José-Antonio
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- Polydopamine-Encapsulated Dendritic Organosilica Nanoparticles as Amphiphilic Platforms for Highly Efficient Heterogeneous Catalysis in Water
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Aqueous heterogeneous catalysis is a green, sustainable catalytic process that attracts increasing attention, but it often suffers from poor mass transfer, substrate adsorption and catalyst dispersion. Herein, we synthesized a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine (PDA) shell and a hydrophobic dendritic organosilica nanoparticle (DON) core for heterogeneous catalysis in water. The hydrophilic shell allowed the catalyst dispersing well in water, and the hydrophobic core facilitated the absorption of organic reactants. The hierarchical core-shell structure facilitated rational arrangement of the location of catalytic species to match the reaction sequence. The obtained metal, enzyme and metal-enzyme amphiphilic catalysts demonstrated improved stability, selectivity and activity in aqueous reactions, including Pd-catalyzed cross-couplings (Suzuki, Liebeskind-Srogl, Heck and Sonogashira), enzymatic enantioselective reduction, chemoenzymatic cascade synthesis of chiral compounds and chemoenzymatic cascade degradation of organophosphates. The amphiphilic catalysts could be easily in situ recovered, and their high catalytic performance was sustained for five cycles.
- Gao, Jing,Guo, Na,Jiang, Yanjun,Liu, Guanhua,Liu, Pengbo,Liu, Yunting,Wang, Zihan,Zhang, Lei
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supporting information
p. 1975 - 1982
(2021/06/09)
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- Heterogeneous Fe3O4@Si–NHC–Pd Catalyst: Synthesis, Characterization, and Catalytic Activity in the Suzuki–Miyaura Cross-Coupling Reaction under Mild Conditions
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Abstract: A novel Fe3O4@Si–NHC–Pd catalystwith N-heterocyclic carbenes (NHCs) moiety as an alternative ligand tophosphines for metal complexes has been synthesized and characterized by variousmethods. Synthesis of metal nanoparticles has been accomplished withoutaggregation, and the prepared catalyst has been applied in theSuzuki–Miyauracross-coupling reaction of boronic acids and aryl halides in water usingEt3N as a base. The catalyst has demonstrated highefficiency at room temperature and can be easily removed from the reaction mediausing an external magnetic field and recycled at least five times withoutsignificant decrease of its activity.
- Kalishomi, R. Ghavidel,Rostamizadeh, S.
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p. 1140 - 1146
(2021/08/06)
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- Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
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The photoelectric properties and catalytic activities of substituted triphenylphosphine and sulfur/selenium ligand supported aromatic triangular tri-palladium complexes1-4, abbreviated as [Pd3]+, were investigated. The cyclic voltammogram of [Pd3]+in CH3CN-nBu4NPF6showed a single quasi-reversible wave which was consistent with their robust property and provided preliminary proof for their electron transfer processes in catalysis. With excitation at 267 nm, [Pd3]+exhibited strong ratiometric fluorescence at 550 and 780 nm at a temperature gradient from 77 K to 287 K. These peculiar triangular tri-palladium complexes showed excellent catalytic activities and exclusive reactivity with aryl iodides over the other halogenated aromatics in the Suzuki-Miyaura coupling reaction. The electronic and steric hindrance effects of substituents on the aryl iodides and aryl boronic acids including heteroaromatics like pyridine, pyrazine and thiophenes were explored and most substrates achieved up to 99% of yields. (2-[1,1′-Biphenyl]-2-ylbenzothiazole) which was analogous to the selective cyclooxygenase-2 (COX-2) inhibitors was also synthesized with our tri-palladium catalyst and gave good isolated yield (94%). The study of the catalytic process revealed that the mechanism of the reaction may involve the replacement of the sulphur ligand on [Pd3]+by iodine from aryl iodides, which was beneficial for the matching of C-I bond energy.
- Li, Xujun,Li, Jia,Wang, Xiaoshuang,Wu, Lingang,Wang, Yanlan,Maestri, Giovanni,Malacria, Max,Liu, Xiang
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supporting information
p. 11834 - 11842
(2021/09/06)
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- Palladium supported on structurally stable phenanthroline-based polymer nanotubes as a high-performance catalyst for the aqueous Suzuki-Miyaura coupling reaction
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Though the Suzuki-Miyaura coupling reaction has intrinsic advantages in organic synthesis, it is still a challenging task to develop a highly active and truly heterogeneous catalyst for the aqueous Suzuki-Miyaura coupling reaction (SMR). In this work, a series of phenanthroline-based polymers (PBPs; PBP1 to PBP8) were synthesized by a simple one-step AlCl3-catalyzed Friedel-Crafts polymerization method. Systematic measurements of PBPs by N2adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) show that most of the PBPs have a nanosheet morphology, except PBP8 which has both one-dimensional nanotubular morphology and large surface area (745 m2g?1). Benefitting from the porous nanotube morphology and the two N atoms contained in the phenanthroline unit of the polymer structure, polymer PBP8 shows adsorption effects and strong chelating stabilization on the Pd active metal (size, 2-5 nm). The Pd/PBP8 catalyst exhibits superior catalytic activity within 2 h (TOF value: 3077 h?1) and reusability (7 cycles) in the SMR with typical reactants such as bromobenzene, phenylboronic acid and the base of K3PO4.3H2O at 30 °C in a solvent mixture of water and ethanol (VH2O?:?Vethanol= 3?:?2).
- Yang, Didi,Wang, Shuhui,Dan, Ting,Gao, Dashuang,Au, Chaktong,Zhang, Wanju,Zhang, Yan
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p. 12120 - 12128
(2021/07/19)
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- A recyclable self-supported nanoporous PdCu heterogeneous catalyst for aqueous Suzuki-Miyaura cross-coupling
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Nanoporous PdCu (NP-PdCu) was prepared by the dealloying strategy from a PdCuAl ternary alloy precursor and characterized systematically using SEM, TEM, XRD, and XPS. NP-PdCu was demonstrated to be a competent self-supported heterogenous catalyst for Suzuki-Miyaura cross-coupling, affording a series of synthetically valuable biaryl compounds in good to excellent yields. This catalyst could be easily separated from the productviacentrifugation and reused several times without obvious loss of catalytic performance.
- Chen, Jie,Du, Jialei,Liu, Fushan,Wang, Bin,Wang, Leichen,Xia, Hehuan,Xiang, Daili,Xu, Caixia,Zhang, Yuanyuan,Zhao, Yiwei
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supporting information
p. 11641 - 11644
(2021/11/12)
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- Complexes: Easily Synthesized, Highly Active Pd(II)-NHC Precatalysts for Cross-Coupling Reactions
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We report the synthesis, characterization, and reactivity of [(NHC)PdCl2(aniline)] complexes. These well-defined, air- and moisture-stable catalysts are highly active in the Suzuki-Miyaura cross-coupling of amides by N-C(O) activation as well as in the Suzuki-Miyaura cross-coupling of esters, aryl chlorides, and Buchwald-Hartwig amination. Most crucially, this study introduces broadly available anilines as stabilizing ligands for well-defined Pd(II)-NHC catalysts. The availability of various aniline scaffolds, including structural and electronic diversity, has a significant potential in fine-tuning of challenging cross-couplings by Pd-NHCs. The parent catalyst in this class, [Pd(IPr)(AN)Cl2], has been commercialized in collaboration with Millipore Sigma, offering broad access for reaction screening and optimization.
- Xia, Qinqin,Shi, Shicheng,Gao, Pengcheng,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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p. 15648 - 15657
(2021/10/25)
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- Synthesis of ultrafine AuPd bimetallic nanoparticles using a magnetite-cored poly(propyleneimine) dendrimer template and its sustainable catalysis of the Suzuki coupling reaction
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The poly(propyleneimine) PPI dendrimer with active amino groups and specific voids is an excellent template for the encapsulation and stabilization of size and shape-controlled metal nanoparticles. The magnetite-cored PPI dendrimer up to third generation was synthesized by a divergent method in our previous report. Bimetallic nanoparticles are more advantageous than monometallic nanoparticles in catalysis due to their synergistic effect between two metals, especially Au and Pd nanoparticles. Herein, we present the synthesis of highly monodispersed ultrafine AuPd bimetallic nanoparticles of size 3-6 nm using the magnetic-cored PPI dendrimer through a facile and convenient method without external stabilizers. The formation of the monodispersed bimetallic nanoparticles on the dendritic entity was confirmed through HRTEM, HRSEM, EDAX, XRD, XPS and VSM. The excellent structural behavior of the magnetic-cored PPI dendrimers proves their ability to encapsulate AuPd bimetallic nanoparticles, and also attain better dispersibility, stability, and improved efficacy compared to conventional dendrimer-encapsulated metal nanoparticles. Most predominantly, it was isolated by simple magnetic attraction. TheAuPd@PPI@Fe3O4/SiO2nanomaterial was utilized as a potential green catalyst in the Suzuki coupling reaction under ambient reaction conditions with greater reactivity and stability. Coupling products were characterized by1H and13C NMR. This material retained its catalytic activity in the coupling reaction for up to eight consecutive catalytic cycles.
- Rangasamy, Rajmohan,Lakshmi, Kannappan,Selvaraj, Mari
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p. 14227 - 14235
(2021/08/16)
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- Nanocellulose Supported PdNPs as in situ Formed Nano Catalyst for the Suzuki Coupling Reaction in Aqueous Media: A Green Approach and Waste to Wealth
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An effective and highly sustainable method has been developed for the Suzuki coupling reaction of aryl halides and phenylboronic acid using in situ generated nacocellulose (NC) supported palladium nanoparticles (Pd@NC NPs) as heterogeneous catalysts in water. The formation of PdNPs was observed in the absence of additional reagents, during the course of the Suzuki reaction from NC and Pd(OAc)2. In situ formed Pd@NC NPs have been systematically characterized using TEM, EDX, XRD and FT-IR techniques. The in situ generated catalyst was separated and studied for its successful reusability up to 11 cycles. The application of aqueous media, use of in situ formed catalyst, mild reaction conditions, absence of volatile organic solvents, broad substrate scope, high product isolated yields are the significant developments of this protocol. The nanocellulose used for this protocol has been generated form the waste cotton cloth and hence it is an example for the waste to wealth and sustainable approach.
- Aabaka, Sreenath Reddy,Mao, Jincheng,Lavanya, Mallu,Venkateswarlu, Katta,Huang, Zhiyu,Mao, Jinhua,Yang, Xiaojiang,Lin, Chong
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supporting information
(2021/02/21)
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- Supported phosphine free bis-NHC palladium pincer complex: An efficient reusable nanocatalyst for Suzuki-Miyaura coupling reaction
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A periodic mesoporous organosilica material functionalized with a bis-NHC palladium pincer complex was synthesized by sol-gel process. The resulting organic-inorganic hybrid nano material was characterized by XRD, TEM, SEM, TGA analysis, and BET measurements. The hybrid nanomaterial act as highly active catalysts for the Suzuki–Miyaura cross-coupling between deactivated aryl chlorides and phenylboronic acid under heterogeneous and aerobic conditions. The supported catalyst exhibited excellent activity and stability and it could be reused at least ten times without any significant loss of activity. Furthermore, the SEM image revealed that high order mesostructure of the recycled nanocatalyst. After ninth run, catalyst showed almost similar structure as compared to the fresh catalyst. ICP-AES detected no Pd contamination in the products, and leaching tests verified that the reaction was truly heterogeneous.
- Burange, Anand S.,Luque, Rafael,Rajabi, Fatemeh,Voskressensky, Leonid G.
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- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- COMPLEXES OF N-HETEROCYCLIC CARBENES FOR TRANSITION METAL CATALYSIS
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Described herein is a new class of highly active Pd(II)-NHC complexes bearing anilines as throw-away ligands. These catalysts are well-defined, air- and moisture-stable and can be easily purified by chromatographic techniques. High activity and generality has been exemplified in the Suzuki-Miyaura cross-coupling by C-N, C-O and C-Cl cleavage. Facile syntheses of these catalysts is also described.
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Paragraph 31
(2021/07/17)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0085-0092
(2021/02/24)
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- Preparation method of nitrogen-alkyl (deuterated alkyl) aromatic heterocycle and alkyl (deuterated alkyl) aryl ether compound
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The invention provides a method for preparing nitrogen-alkyl(deuterated alkyl)aromatic heterocycle and alkyl(deuterated alkyl)aryl ether compounds. The method adopted in the invention specifically comprises the following steps: firstly, adding an alkoxy base (MOR') or a combination reagent Q (comprising a base M'X, an alcohol C and a molecular sieve E) into a solvent B to be stirred; then, addingan aromatic compound D of nitrogen sulfonyl or oxygen sulfonyl into a mixture; separating and purifying after reaction to obtain nitrogen-alkyl(deuterated alkyl)aromatic heterocycle or alkyl(deuterated alkyl)aryl ether. The method can realize one-step conversion from an electron withdrawing benzenesulfonyl protecting group on a nitrogen or oxygen atom to an electron donating alkyl protecting group, avoids using highly toxic alkyl halide, and has advantages of being efficient, economical, environmentally friendly, mild in condition, good in substrate universality and high in yield; the prepareddeuterated compounds can be widely applied to the fields of pharmaceutical chemistry and organic chemistry synthesis.
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Paragraph 0093-0098
(2021/04/03)
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- Novel N-heterocyclic carbene cyclic palladium compound as well as preparation method and application thereof
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The invention discloses a novel N-heterocyclic carbene cyclic palladium compound as well as a preparation method and application thereof, and belongs to the technical field of organic catalysis. The novel N-heterocyclic carbene cyclic palladium compound is prepared by the following steps: heating, stirring and mixing N-(4-butoxybenzyl)-N-ethylethylamine, palladium chloride and an organic solvent in an inert gas atmosphere, then adding potassium carbonate, performing stirring and mixing, and finally adding 1-(2,6-diisopropyl phenyl)-3-butyl-brominated imidazole for reflux reaction; and after the reaction is finished, performing quenching with an acid solution, performing extracting to obtain a crude product, and performing column chromatography separation and purification to obtain the novel N-heterocyclic carbene cyclic palladium compound. The N-heterocyclic carbene cyclic palladium compound provided by the invention has high catalytic activity, can catalyze cross-coupling reactions between aryl chloride and aryl phenylboronic acid and between aryl chloride and secondary amine in a catalytic amount of 1 mol%, and can be used as a high-efficiency catalyst for the coupling reactions.
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Paragraph 0038-0040
(2021/06/26)
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- Magnetic nanoparticles supported N-heterocyclic palladium complex: Synthesis and catalytic evaluations in Suzuki cross-coupling reaction
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Because of the robustness and magnetic properties, the magnetic materials are promising and alternative candidate for the fabrication of noble metal in chemical catalysis from the viewpoint of green chemistry. Accordingly, an eco-friendly magnetic palladium catalyst loaded on N-Methylimidazole functionalized Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2-NMIM-Pd) has been designed and prepared in the present work. The resultant composite exhibited excellent catalytic activity towards the Suzuki cross-coupling reaction for the synthesis of the corresponding biaryls in good to excellent yields (up to 96%) under aerobic conditions. In particular, this catalyst could be easily recovered through magnetic separation in a few cycles. The as-prepared palladium complex showed advantages including high thermal stability, low toxicity, moisture and oxygen insensitivities in Suzuki reactions. More importantly, this study presents a catalysis system, which will provide the magnetic materials access to the potential applications in a wide range of green organic catalysis.
- Dong, Yahao,Xue, Fengjun,Wei, Yuping
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- Easily synthesizable benzothiazole based designers palladium complexes for catalysis of Suzuki coupling: Controlling effect of aryl substituent of ligand on role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)
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The present report is based on straightforward synthesis of molecular palladium complexes of benzothiazole based bulky ligands. Catalytic potential of 1[Pd(L1)2Cl2] and 2[Pd(L2)2Cl2] has been screened for Suzuki coupling. Due to structural difference between 1 and 2 (anthracen-9-yl in 1, and pyren-1-yl in 2), they behave as designers pre-catalysts and show different catalytic behaviour and nature by dispensing the nanoparticles of different materials (PdS by 1 and Pd16S7 by 2). This is an unprecedented observation as the size of the aryl substituent controls the efficiency (efficiency: 1 > 2) through determining the composition and nature of insitu generated nanoparticles.
- Arora, Aayushi,Kumar, Arun,Kumar, Sushil,Oswal, Preeti,Rao, Gyandshwar Kumar,Singh, Ajai K.,Singh, Siddhant
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- Triptycene carbene palladium compound and application thereof
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The invention discloses a triptycene carbene palladium compound and an application thereof, the structural formula of the triptycene carbene palladium compound is represented by a formula I or a formula II; compared with a conventional metal palladium catalyst, the triptycene carbene palladium compound is simple and convenient to prepare, high in yield and suitable for various substrates, the usage amount of the catalyst can be reduced to one ten thousandth, and the triptycene carbene palladium compound has a good catalytic effect on various metal palladium catalytic reactions; and the triptycene carbene palladium compound has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0101-0108
(2021/05/08)
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Bimetallic nano alloy architecture on a special polymer: Ni or Cu merged with Pd for the promotion of the Mizoroki–Heck reaction and the Suzuki–Miyaura coupling
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Abstract: Novel Ni-Pd and Cu-Pd bimetallic nano alloys was designed and heterogenized on the highly robust ABPBI [poly(2,5-benzimidazole)] polymer in high yields using NaBH4 as reducing agent. These were versatile ligand free catalysts for the Mizoroki–Heck reaction and Suzuki–Miyaura coupling. The bimetallic Ni-Pd-ABPBI catalyst for the Mizoroki–Heck reaction of 4-iodo anisole could be recycled 5 times with high yields. Aryl bromides could also be activated for the Mizoroki–Heck reaction using Cu-Pd-ABPBI NP catalysts, with moderate yields. Graphic abstract: Synopsis Novel bimetallic Ni-Pd and Cu-Pd nano alloys, heterogenized on the robust ABPBI [poly(2,5-benzimidazole)] polymer using NaBH4 as reducing agent, is described. These were versatile ligand free, noble metal conservative catalysts, for the Mizoroki–Heck reaction and the Suzuki–Miyaura coupling. Aryl bromides were activated for the Mizoroki–Heck reaction using the Cu-Pd-ABPBI catalyst.[Figure not available: see fulltext.]
- Patil, Vijay P,Kashid, Abhijit A,Solanki, Bhanupratap S,Kharul, Ulhas K,Iyer, Suresh
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- Hexagonal Boron Nitride Supported N-Heterocyclic Carbene-Palladium(II): A New, Efficient and Recyclable Heterogeneous Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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Abstract: In this study, a new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed and synthesized. The structure of the h-BN@NHC-Pd heterogeneous catalyst was characterized by various techniques such as Fourier transform infrared spectra (FT-IR), ultraviolet–visible spectroscopy (UV–Visible), inductively coupled plasma-optical emission spectroscopy (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). Then catalytic activity of h-BN@NHC-Pd heterogeneous catalyst was studied in the Suzuki–Miyaura cross-coupling reactions between aryl halides and arylboronic acids in aqueous medium at room temperature. The effects of varying solvents, bases, temperature, time and catalytic ratios on the performance of the Suzuki–Miyaura cross-coupling reaction were investigated. Moreover, h-BN@NHC-Pd heterogeneous catalyst could be easily recovered through simple filtration or centrifugation method and could be reused five times without significant loss of its catalytic efficiency. Furthermore, stability of the h-BN@NHC-Pd heterogeneous catalyst after recycling was confirmed through FESEM and FT-IR techniques. The h-BN@NHC-Pd heterogeneous catalyst shows remarkable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easily separable and high stability without leaching. Graphic Abstract: A new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed, synthesized, characterized and catalytic activity was studied in the Suzuki–Miyaura cross-coupling reactions. [Figure not available: see fulltext.]
- Antony, Arnet Maria,Kandathil, Vishal,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
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p. 1293 - 1308
(2020/10/06)
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- Ultrafine and Highly Dispersed Pd/SiO2 for Suzuki?Miyaura Cross-coupling Reactions
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Abstract: Construction of heterogeneous Pd/SiO2 catalyst via the pollution-free strategy marked strong electrostatic adsorption has been reported for the application to Suzuki–Miyaura cross-coupling reactions. The exposed negatively charged oxygen groups, which were converted from the hydroxyl groups on the surface of silica under the alkaline atmosphere, could effectively anchor palladium species to form ultrafine Pd nanoparticles (Pd NPs) with an average particle size of 1.3?nm and high dispersion (43%). Pd/SiO2 catalyst was endowed with the excellent catalytic performance which was that the yield of the Suzuki–Miyaura reaction between bromobenzene and phenylboronic acid at 40?°C was > 99% for 30?min and the TOF was ~ 80,000?h?1. The catalyst could be easily recovered and recycled by facile procedure without a significant decrease in catalytic activity, which was able to maintain the 90% yield after repeated for 8 times. In addition, a continuous flow reaction device was designed using the Pd/SiO2 catalyst to effectively improve the production efficiency of biphenyl. Graphic Abstract: Pd/SiO2 catalyst constructed with the strategy of strong electrostatic adsorption (SEA) possesses uniformly dispersed and highly exposed Pd sites which can be easily transformed into electron-deficient Pdδ+ and strengthened stability for itself due to its strong interaction with the front surface of the carrier, and has been endowed the outstanding catalytic performance for Suzuki?Miyaura cross-coupling reaction. [Figure not available: see fulltext.]
- Fan, Xizheng,Yang, Jingyi,Pang, Qingqing,Liu, Zhongyi,Zhang, Panke,Yang, Jing-He
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p. 2291 - 2301
(2021/01/04)
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- Molecular engineered palladium single atom catalysts with an M-C1N3subunit for Suzuki coupling
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Single atom catalysis has emerged as a powerful technique for catalysis due to its outstanding performance and atom economy. Controlling the hybridization of the atom with its environment is crucial in determining the selectivity and/or yield of the reaction. However, the single atom environment is usually ill-defined and hard to predict because the pyrolysis process used in preparing SACs damages the original status of the precursors in the catalyst preparation. A molecular engineering approach to synthesize single atom catalysts (SACs) on a heterogeneous template provides a strategy to make SACs with a highly uniform coordinating environment. Herein, we report the preparation of a molecular engineered Pd single atom catalyst with a pre-defined M-N3C1 coordination (Pd-N3C1-SAC) using a structure-rigid Pd-N3C1 porphyrin as the precursor, which shows more efficient Suzuki coupling compared with the SAC with Pd-N4 coordination. The origin of the high activity of the Pd-N3C1-SAC is revealed through density functional theory calculations, where a lower reaction barrier for the rate-determining oxidative addition is identified. This journal is
- Liu, Jia,Chen, Zhongxin,Liu, Cuibo,Zhang, Bao,Du, Yonghua,Liu, Chen-Fei,Ma, Lu,Xi, Shibo,Li, Runlai,Zhao, Xiaoxu,Song, Jingting,Sui, Xin Zhi,Yu, Wei,Miao, Ling,Jiang, Jianjun,Koh, Ming Joo,Loh, Kian Ping
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supporting information
p. 11427 - 11432
(2021/05/19)
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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- Synthesis of tetranuclear complex of Pd(II) with thiosemicarbazone ligands derived from 2-quinolone and its catalytic evaluation in Suzuki–Miyaura-type coupling reactions and alkoxylation of chloroquinolines
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A tetranuclear palladium(II) complex [(Pd(H-6MOQtsc-Ph))4] was obtained from the reaction between 6-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4(N)-phenylthiosemicarbazone [H2-6MOQtsc-Ph] and K2[PdCl4]. The ligand and the Pd(II) complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV–visible and 1H NMR spectroscopy. X-ray diffraction studies confirmed the tetrameric nature of the complex with the coordination of ligand through quinolone carbonyl, azomethine nitrogen and thiolate sulfur atoms, and the fourth site is occupied by 2-quinolone nitrogen atom of the adjacent ligand. The synthesized complex was tested as catalyst in Suzuki–Miyaura coupling reaction between various chloroquinoline derivatives with phenylboronic acid. The reactions afforded unexpected C-alkoxylated (C-O coupling) products instead of more expected C-arylated (C-C coupling) products in the respective alcoholic mediums. However, the reactions with traditional aryl halides probed with very good yield of the corresponding C-C coupling products.
- Nandhini, Sundar,Dharani, Sivadasan,Elamathi, Chennakrishnan,Dallemer, Frederic,Prabhakaran, Rathinasabapathi
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- Water-Dispersible Pd–N-Heterocyclic Carbene Complex Immobilized on Magnetic Nanoparticles as a New Heterogeneous Catalyst for Fluoride-Free Hiyama, Suzuki–Miyaura and Cyanation Reactions in Aqueous Media
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Abstract: Pd–N-heterocyclic carbine complex immobilized on magnetic nanoparticles is synthesized and characterized by different techniques such as FT-IR, XPS, TEM, EDX, FESEM, VSM, TGA, and ICP. The synthesized catalyst was used as a new water dispersible heterogeneous catalyst in the fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water. By this method, different types of biaryls and aryl nitriles were synthesized in good to high yields by the reaction of a variety of aryl iodides, bromides and chlorides with triethoxyphenylsilane, phenylboronic acid and K4[Fe(CN)6]·3H2O, respectively. The presence of sulfonates as hydrophilic groups on the surface of the catalyst confers a highly water dispersible, active and yet magnetically recoverable Pd catalyst. The possibility to perform the reaction in water as a green medium, ease of the catalyst recovery and reuse by magnetic separation, and the absence of any additives or co-solvents make this method as an eco-friendly and economical protocol for the synthesis of biaryl derivatives and aryl nitriles. Graphic Abstract: A new water dispersible heterogeneous Pd–N-heterocyclic carbene for the efficient fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water is developed.[Figure not available: see fulltext.].
- Chahkamali, Farhad Omarzehi,Sansano, José Miguel,Sobhani, Sara
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- Fe-MIL-101 modified by isatin-Schiff-base-Co: a heterogeneous catalyst for C-C, C-O, C-N, and C-P cross coupling reactions
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A metal-organic framework functionalized with a cobalt-complex is preparedviapost-synthetic modification of Fe-MIL-101-NH2. Initially, Fe-MIL-101-NH2reacted with isatin to produce Fe-MIL-101-isatin-Schiff-base, which can anchor the cobalt by the addition of cobalt acetate. The resulting MOF-Co catalyst is characterized by employing multiple techniques. This new modified MOF acts as a heterogeneous and recyclable catalyst for efficient Ullmann, Buchwald-Hartwig, Hirao, Hiyama and Mizoroki-Heck cross-coupling reactions of several aryl halides/phenylboronic acid/phenyltosylate with phenols, anilines/heterocyclic amines, triethyl phosphite, triethoxyphenylsilane and alkenes and generates the expected coupling products in good to high yields.
- Farrokhi, Alireza,Rouzifar, Majid,Sansano, José Miguel,Sobhani, Sara
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p. 19963 - 19976
(2021/11/12)
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- Efficient photocatalytic chemoselective and stereoselective C-C bond formation over AuPd@N-rich carbon nitride
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Heterogeneous chemoselective or stereoselective C-C coupling reactions remain extremely challenging in traditional organic synthesis. Here, we constructed a AuPd@N-rich carbon nitride (NRCN) photocatalyst through simple ammonia solution heat treatment of carbon nitride and then AuPd NP loading. AuPd@NRCN exhibited extraordinary light color promoted catalytic performance in C-C bond formation under visible light in air. Surprisingly, both high chemoselectivity to unsymmetrical Ullmann biaryl products and satisfactory stereoselectivity to Z-type Heck reaction products could be achieved by changing the light source color. Various substrates exhibited great potential for the economical synthesis of unsymmetrical biaryl products and Z-type olefins. Efficient visible light promoted C-I bond activation accompanied with improved photocatalytic coupling reaction efficiency over AuPd@NRCN was verified firstly by in situ DRIFTS. Considering that the Ullmann cross-coupling reaction is a multi-photon reaction, the improved photocatalytic performance in the Ullmann cross-coupling reaction using a combination of light sources with different colors might be due to the activation of different substrates and/or steps requiring different energies, and the combination of the two energy sources was beneficial for improving the activation efficiency of different substrates and/or steps. The activation of iodobenzene and styrene in the Heck reaction with light was also beneficial to the formation of the stilbene product. The light color promoted chemoselectivity and stereoselectivity are expected to have profound impact on organic synthetic methodology improvement. This journal is
- Jiang, Heyan,Xu, Jie,Zhang, Sishi,Cheng, Hongmei,Zang, Cuicui,Bian, Fengxia
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p. 219 - 229
(2021/01/28)
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- Ligand and Base Free Synthesis of Biaryls from Aryl Halides in Aqueous Media with Recyclable Ti0.97Pd0.03O1.97 Catalyst
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Abstract: Facile protocol for the synthesis of biaryls from aryl halides in presence of magnesium metal without prior formation of organometallic intermediate has been exploited. Irrespective of aqueous medium, Ti0.97Pd0.03O1.97 catalyst supports C–C bond formation reaction in presence of metals rather than dehalogenation without any additives. Homocoupling of 16 different aryl halides furnished corresponding biphenyls in good yield with better functional group tolerance. The recovery of the catalyst was carried out by employing catalyst coated cordierite monolith up to 7th cycle with high yields. A new approach for the cross-coupling reaction is also attempted. Graphic Abstract: [Figure not available: see fulltext.]
- Prasanna,Bhat, Shrikanth K.,Usha,Hegde
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p. 3313 - 3322
(2021/03/04)
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- Introduction of a Recyclable Basic Ionic Solvent with Bis-(NHC) Ligand Property and The Possibility of Immobilization on Magnetite for Ligand- and Base-Free Pd-Catalyzed Heck, Suzuki and Sonogashira Cross-Coupling Reactions in Water
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A new versatile and recyclable NHC ligand precursor has been developed with ligand, base, and solvent functionalities for the efficient Pd-catalyzed Heck, Suzuki and Sonogashira cross-coupling reactions under mild conditions. Furthermore, NHC ligand precursor was immobilized on magnetite and its catalytic activity was also evaluated towards the coupling reactions as a heterogeneous catalyst. The NHC ligand precursor was prepared with imidazolium functionalization of TCT followed by a simple ion exchange by hydroxide ions. However, the results revealed an excellent catalytic activity for the both homogeneous and heterogeneous catalytic systems. 1.52?g.cm?3 and 1194 cP was obtained for the density and viscosity of the NHC ligand precursor respectively. On the other hand, the heterogeneous type could be readily recovered from the reaction mixture and reused for several times while preserving its properties. Heterogeneous nature of the magnetic catalyst was studied by hot filtration, mercury poisoning, and three-phase tests. High to excellent yields were obtained for all entries for the both homogeneous and heterogeneous catalysts, which reflects the high consistency of the catalyst. Graphic Abstract: [Figure not available: see fulltext.]
- Min, Qingwang,Miao, Penghua,Chu, Deyu,Liu, Jinghan,Qi, Meijuan,Kazemnejadi, Milad
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p. 3030 - 3047
(2021/02/16)
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- Surface engineered Iridium-based magnetic photocatalyst paving a path towards visible light driven C-H arylation and cyanation reaction
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The report presents the fabrication and application of a highly versatile, magnetic and robust iridium based photoredox nanocatalyst. Herein, Ir(PPy)3 based photocatalyst sites have been chemically engineered over the magnetic nanoparticles to encompass the captivating features of homogeneous iridium photocatalyst with the magnetically recyclable core. A household photoreactor was designed and fabricated to achieve highly selective visible light driven oxidative C-H arylation and C-H cyanation under sustainable and ambient reaction conditions utilizing the Ir@PyBz@ASMNPs photoredox nanocatalyst. The environment friendly Ir@PyBz@ASMNPs shows excellent photocatalytic activity, broad substrate adaptability and outstanding recyclability compared to the analogous homogeneous catalysts. Indeed, the Ir@PyBz@ASMNPs possess some key features including high surface area, high iridium metal loading and excellent stability. This work is expected to enlighten and provide new insights in the rational design of high performance and recoverable photoredox nanocatalyst through surface engineering strategy.
- Gaur, Rashmi,Gawande, Manoj B.,Kaushik, Bhawna,Rana, Pooja,Sharma, Priti,Sharma, Rakesh K.,Yadav, Priya,Yadav, Sneha
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p. 297 - 308
(2021/08/23)
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- C–H Arylation of Benzene with Aryl Halides using H2 and a Water-Soluble Rh-Based Electron Storage Catalyst
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This paper reports the first example of C?H arylation of benzene under mild conditions, using H2 as an electron source {turnover numbers (TONs)=0.7–2.0 for 24 h}. The reaction depends on a Rh-based electron storage catalyst, and proceeds at room temperature and in aqueous solution. Furthermore, the H2 is inactive during the radical transfer step, greatly reducing unwanted side reactions.
- Yatabe, Takeshi,Tome, Tamon,Takahashi, Yukina,Matsumoto, Takahiro,Yoon, Ki-Seok,Nakai, Hidetaka,Ogo, Seiji
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supporting information
p. 17326 - 17330
(2021/10/29)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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p. 6367 - 6374
(2021/09/29)
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- Nickel(II) complexes with N,O-donor thiopseudourea ligands: Syntheses, structures, and catalytic applications in Kumada–Corriu cross-coupling reactions
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Synthesis, characterization, and physical properties of benzyl-N′-(4-R-benzoyl)-N-(2,6-diisopropylphenyl)carbamimidothioates, HL1 (R = H) and HL2 (R = Cl), and their nickel(II) complexes having the general molecular formula [Ni(L1/2)2] (1 and 2) have been reported. Elemental analysis, magnetic susceptibility, solution electrical conductivity, and various spectroscopic (IR, UV–Vis, and 1H NMR) measurements were used to characterize HL1, HL2, and the two complexes (1 and 2). The molecular structures of all four compounds were determined by single-crystal X-ray crystallographic studies. The structures of HL1 and HL2 showed the imino-ketone form of both compounds. In each of 1 and 2, the six-membered chelate ring forming iminolate-O and azomethine-N donor two (L1/2)? ligands form a square-planar trans-N2O2 coordination environment around the metal center. The spectroscopic characteristics of HL1, HL2, 1, and 2 are consistent with their molecular structures. Both complexes were successfully employed as efficient catalysts in Kumada–Corriu C-C cross-coupling reactions of aryl bromides with phenylmagnesium bromide. The reactions provided biaryl products in good to excellent yields with a good substrate scope.
- Shakunthala, Kinche,Srivastava, Ankit Kumar,Babu, G. Narendra,Keesara, Srinivas,Pal, Samudranil
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- Synthesis of arylboronates via the Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates with bis(pinacolato)diboron
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The desulfitative borylation reaction of sodium arylsulfinates with bis(pinacolato)diboron or bis(neopentylglycolato)diboron under palladium catalysis has been developed, allowing selective C-B bond formation to give arylboronates with a range of functional groups in moderate to good yields under mild reaction conditions. A gram-scale preparation as well as the cascade Suzuki-Miyaura cross-coupling of arylboronates demonstrated the potential practical utility in organic synthesis.
- Qiu, Di,Li, Songyi,Yue, Guanglu,Mao, Jinshan,Xu, Bei,Yuan, Xinyu,Ye, Fei
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supporting information
(2021/11/04)
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- Effect of Alkyl Structures on the Anti-stacking and Anchoring of Pd/Diamine-Functionalized Graphene Nanoparticles in Application in Suzuki Reaction
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Three diamines (1,8-diaminooctane/p-phenylenediamine/biphenylenediamine) with different alkyl groups were used to synthesize the functionalized graphene networks. Pd as the common metal catalyst was used to explore the effects of alkyl types of diamines on anti-stacking, metal anchoring ability of functional graphene and hence the catalytic performance. The results were discussed by characterization of the material and its catalytic properties. All catalysts showed excellent catalytic performance on the Suzuki cross-coupling reaction with a high yield of up to 100%. The p-phenylenediamine and biphenylenediamine functionalized graphene with larger specific surface area was beneficial to improve the stability of the graphene catalyst and maintain good catalytic activity after 5 cycles. The Pd nanoparticles in 1,8-octanediamine materials have smaller size and a smaller loading with the same or even better catalytic performance than p-phenylenediamine, biphenylenediamine materials, due to the stronger electron donating ability of N of octanediamine than that of p-phenylenediamine.
- Tian, Yinbing,Tang, Zijie,Ru, Yu,Wang, Yuanyuan,Dai, Liyi
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p. 2745 - 2754
(2021/08/09)
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