- Nickel-catalysed direct C2-arylation of N-heterocyclic carbenes
-
A highly efficient nickel catalysed method for the direct C2-arylation of N-heterocyclic carbenes (NHCs) is reported. This protocol enables a facile access to C2-arylated imidazolium salts (NHC-Ar)X (X = Cl, Br, I or OTf). Experimental and theoretical studies suggest the viability of a Ni(i)/Ni(ii) catalytic pathway in which the dinuclear Ni(i) species [(NHC)NiX]2 plays a key role.
- Ho, Nga Kim T.,Neumann, Beate,Stammler, Hans-Georg,Menezes Da Silva, Vitor H.,Watanabe, Daniel G.,Braga, Ataualpa A. C.,Ghadwal, Rajendra S.
-
-
Read Online
- N-heterocyclic carbenes: III. N-heterocyclic carbene ligands based on abietane in Suzuki-Miyaura reaction
-
By reactions of N-alkyl- and N-arylimidazoles with methyl 12-bromoacetyldehydroabietate a series of unsymmetrically substituted chiral imidazolium bromides with the abietane fragment was synthesized. The salts obtained were suggested as new N-heterocyclic carbene ligands in the Suzuki-Miyaura reaction.
- Glushkov,Valieva,Maiorova,Baigacheva,Gorbunov
-
-
Read Online
- Single crystal to single crystal (SC-to-SC) transformation from a nonporous to porous metal-organic framework and its application potential in gas adsorption and Suzuki coupling reaction through postmodification
-
A new amino-functionalized strontium-carboxylate-based metal-organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC-to-SC) transformation upon desolvation. Both structures have been characterized by single-crystal X-ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent £NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine-2-carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross-coupling reaction. The compound shows high activity towards the C£C cross-coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m2 g-1. The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities.
- Sen, Rupam,Saha, Debraj,Koner, Subratanath,Brand?o, Paula,Lin, Zhi
-
-
Read Online
- The study and application of three highly porous hyper-crosslinked catalysts possessing similar catalytic centers
-
Three new catalysts, in which salen ligands were successfully locked in knitting network polymers, were synthesized through the Friedel-Crafts reaction. As a result, the catalysts possessed high specific surface area as high as 512 m2/g with micro-/mesoporous structures, and showed layered morphologies. Owing to the high surface area, the abundant active centers and pores, the Poly-salen-a-Pd(II) displayed superior performance in the Suzuki-Miyaura coupling reaction of various substrates. In particular, the effect from similar catalytic centers for the catalytic properties and stability was investigated by a series of experiments and analyses such as thermogravimetric analysis (TGA), scanning and transmission electron microscopies (SEM and TEM), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS). Notably, three catalysts showed high activity in the reaction, and displayed excellent performance in the hot filtration experiments. This strategy is very cost-effective and convenient, which was highly suggestive to diverse professional audiences in a wide range of heterogeneous catalyst design and application.
- Bi, Jiajun,Dong, Yahao,Meng, Di,Zhu, Dajian,Li, Tao
-
-
Read Online
- Late stage Pd-catalyzed C-H bond functionalization: A powerful tool for the one step access to arylated Cyproheptadine and cyclobenzaprine derivatives
-
The reactivity of Cyproheptadine and Cyclobenzaprine in Pd-catalyzed arylation via C-H bond functionalizations was investigated. From Cyproheptadine using aryl bromides as aryl sources and 5 mol% of a palladium catalyst, the C10-arylated Cyproheptadine derivatives were regioselectively obtained. The highest yields were obtained with electron-rich aryl bromides, but the reaction tolerated useful functional groups on the aryl bromide such as dimethylamino, methoxy, hydroxyl, alkyl, aryl, fluoro, chloro and trifluoromethyl. Cyclobenzaprine was also reactive under the same reaction conditions.
- Atoui, Dhieb,Li, Haoran,Ben Salem, Ridha,Roisnel, Thierry,Caytan, Elsa,Soulé, Jean-Fran?ois,Doucet, Henri
-
-
Read Online
- Synthesis of Symmetric and Nonsymmetric NiII Thiophosphinito PECSP (E = S, O) Pincer Complexes and Their Applications in Kumada Coupling under Mild Conditions
-
The reaction of 1,3-dimercaptobenzene with iPr2PCl in the presence of the base NaH, furnishes the symmetric ligand [C6H4-1,3-(SPiPr2)2] (1a). The direct reaction of this ligand as well as of the literature-known nonsymmetric ligand [C6H4-1-(SPiPr2)-3-(OPiPr2)] (1b) with NiCl2 affords the symmetric bis(thiophosphinito) PSCSP pincer complex [{C6H3-2,6-(SPiPr2)2}NiCl] (2a) as well as the phosphinito–thiophosphinito POCSP pincer complex [{C6H3-2-(SPiPr2)-6-(OPiPr2)}NiCl] (2b). Both complexes were fully characterised and their catalytic performance in Kumada coupling of aryl halides and p-tolylmagnesium bromide under mild conditions was evaluated.
- Hasche, Patrick,Joksch, Markus,Vlachopoulou, Georgia,Agarwala, Hemlata,Spannenberg, Anke,Beweries, Torsten
-
-
Read Online
- Catalytic activation of a single C-F bond in trifluoromethyl arenes
-
Synthetic methods for the direct transformation of ArCF3 to ArCF2R would enable efficient diversification of trifluoromethyl arenes and would be of great utility in medicinal chemistry. Unfortunately, the development of such methods has been hampered by the fundamental properties of C-F bonds, which are exceptionally strong and become stronger with increased fluorination of the carbon atom. Here, we describe a method for the catalytic reduction of ArCF3 to ArCF2H through a highly selective activation of a single C-F bond. Mechanistic studies reveal separate reaction pathways for the formation of ArCF2H and ArCH3 products and point to the formation of an unexpected intermediate as the source of the unusual selectivity for the mono-reduction.
- Dang, Hester,Whittaker, Aaron M.,Lalic, Gojko
-
-
Read Online
- A new aspect of nickel-catalyzed Grignard cross-coupling reactions: Selective synthesis, structure, and catalytic behavior of a T-shape three-coordinate nickel(I) chloride bearing a bulky NHC ligand
-
Novel T-shape three-coordinate nickel(I) chlorides bearing an N-heterocyclic carbene ligand, NiCl(IPr)2 (IPr = 1,3-bis-(2,6- diisopropylphenyl)imidazolin-2-ylidene), were isolated by a reaction of Ni(0)(NHC)2 with aryl chlorides. This Ni(I) complex was shown to act as a catalyst in a cross-coupling reaction of aryl halides with phenylmagnesium chloride. The Royal Society of Chemistry 2010.
- Miyazaki, Satoshi,Koga, Yuji,Matsumoto, Taisuke,Matsubara, Kouki
-
-
Read Online
- Iron(II) Corrole Anions
-
Reduction of [Fe(TPC)(THF)] (TPC = trianion of 5,10,15-Triphenylcorrole) with KC8 generates the iron(II) corrole anion, K(THF)2[FeII(TPC)] (3a). Compound 3a represents the first example of an isolated and crystallographically characterized corrole complex of divalent iron. The compound adopts an intermediate-spin state (S = 1), displaying square-planar geometry about the iron atom. All-electron density functional theory (OLYP and B3LYP) calculations with STO-TZP basis sets indicate two essentially equienergetic d electron configurations, dxy2dz22dxz1dyz1 (occupation 1) and dxy2dz21dxz1dyz2 (occupation 2), as likely contenders for the ground state of [FeII(TPC)]-, with the optimized geometry of the former in slightly better agreement with the low-Temperature X-ray structure. Solutions of 3a react with carbon monoxide to afford the low-spin (S = 0) complex, [Fe(TPC)(CO)]-, whereas introduction of oxygen at-78 °C leads to a putative O2 adduct, [Fe(TPC)(O2)]-, which decays rapidly even at low temperatures. Treatment of 3a with organic electrophiles results in formal oxidative addition to give both iron(III) and iron(IV) corrole species. With iodomethane, [Fe(TPC)Me] is produced, illustrating the first instance of alkyl ligand coordination in an iron corrole complex.
- Caulfield, Kenneth P.,Conradie, Jeanet,Arman, Hadi D.,Ghosh, Abhik,Tonzetich, Zachary J.
-
-
Read Online
- Palladium-bisimidazol-2-ylidene complexes as catalysts for general and efficient Suzuki cross-coupling reactions of aryl chlorides with arylboronic acids
-
A series of bisimidazolium salts 1-6 were synthesized and evaluated as precursors to bisimidazol-2-ylidene ligands in palladium-catalyzed Suzuki cross-coupling reactions with aryl chlorides and arylboronic acids. The bisimidazolium salt 6 was found to be superior over imidazolium and other bisimidazolium salts affording high yields of biaryl products employing a wide variety of substrates. (C) 2000 Elsevier Science Ltd.
- Zhang, Chunming,Trudell, Mark L.
-
-
Read Online
- Standard enthalpies of formation of 4-methylbiphenyl and 4,4-dimethylbiphenyl
-
The energies of combustion of 4-methylbiphenyl and 4,4-dimethylbiphenyl in the crystal state were measured in a precision calorimeter equipped with a self-sealing bomb at 298.15 K. The enthalpies of vaporization of these substances were measured in an isothermal heat-conducting Calvet microcalorimeter. Standard enthalpies of formation were calculated for 4-methylbiphenyl and 4,4-dimethylbiphenyl in the crystal, liquid, and gas states.
- Pimenova,Pashchenko,Miroshnichenko,Nesterov
-
-
Read Online
- Phosphonate functionalized N-heterocyclic carbene Pd(II) complexes as efficient catalysts for Suzuki-Miyaura cross coupling reaction
-
A N-heterocyclic carbene (NHC) ligand, L1 bearing a pendant phosphonate ester group is used to prepare two new NHC-Pd(II) complexes, [Pd(L1)2I2] (1) and [Pd(L1)(py)I2] (2) (py = pyridine). Hydrolysis of phosphonate ester group in 2 results another Pd(II)-NHC complex, [Pd(L2)(py)I2] (3) where a phosphonic acid group is attached to the NHC ligand L2. All the three complexes are characterized by analytical and spectroscopic studies while the molecular structures of 1-2 are also determined by single crystal X-ray diffraction measurement. The catalytic efficacies of 1-3 in Suzuki-Miyaura cross coupling reactions of aryl halides and aryl boronic acid are investigated. DFT calculations were performed to decipher the role phosphonate ester or phosphonic acid substituents on the catalytic efficacy.
- Bhattacharyya, Bagmita,Gogoi, Nayanmoni,Guha, Ankur Kanti,Kalita, Amlan Jyoti
-
-
Read Online
- Enhanced emission and its switching in fluorescent organic nanoparticles
-
A new class of organic nanoparticles (CN-MBE nanoparticles) with a mean diameter of ca. 30-40 nm, which exhibit a strongly enhanced fluorescence emission, were prepared by a simple reprecipitation method. CN-MBE (1-cyano-trans-1,2-bis-(4′-methylbiphenyl)ethylene) is very weakly fluorescent in solution, but the intensity is increased by almost 700 times in the nanoparticles. Enhanced emission in CN-MBE nanoparticles is attributed to the synergetic effect of intramolecular planarization and J-type aggregate formation (restricted excimer formation) in nanopaticles. On/off fluorescence switching for organic vapor was demonstrated with CN-MBE nanoparticles.
- An, Byeong-Kwan,Kwon, Soon-Ki,Jung, Sang-Don,Park, Soo Young
-
-
Read Online
- A Kumada Coupling Catalyst, [Ni{(Ph2P)2N(CH2)3Si(OCH3)3-P,P′}Cl2], Bearing a Ligand for Direct Immobilization onto Siliceous Mesoporous Molecular Sieves
-
The ligand-exchange reaction between [Ni(PPh3)2Cl2] and (Ph2P)2N(CH2)3Si(OCH3)3 afforded the novel NiII complex [Ni{(Ph2P)2N(CH2)3Si(OCH3)3-P,P′}Cl2] (1) in which the square-planar NiP2Cl2 coordination sphere contains a four-membered Ni-P-N-P ring. Comparison of the structure of 1 and related NiII square-planar or Ni0 tetrahedral complexes containing similar P-N-P ligands shows that the magnitude of the P-Ni-P angle is controlled by the presence of the Ni-P-N-P ring, irrespective of the geometry of the nickel coordination sphere. Direct anchoring of 1 onto SBA-15 molecular sieves through the trimethoxysilyl end-group of the ligand afforded heterogeneous catalyst 1/SBA-15. Both 1 and 1/SBA-15 catalyze Kumada cross-coupling reactions, exhibiting similar activity and a slightly higher product selectivity than the [Ni{Ph2P(CH2)3PPh2-P,P′}Cl2] and [Ni{(Ph2P)2N-(S)-CHMePh-P,P′}X2] (X = Cl, Br) complexes described in the literature. The Grignard reagent employed is likely to induce leaching of the catalyst, which retains its activity in solution.
- Stamatopoulos, Ioannis,Giannitsios, Dimitrios,Psycharis, Vassilis,Raptopoulou, Catherine P.,Balcar, Hynek,Zukal, Arno?t,Svoboda, Jan,Kyritsis, Panayotis,Vohlídal, Ji?í
-
-
Read Online
- Synthesis and characterization of palladium nanoparticles immobilized on graphene oxide functionalized with triethylenetetramine or 2,6-diaminopyridine and application for the Suzuki cross-coupling reaction
-
Graphene oxide (GO) was functionalized with two organic ligands, triethylenetetramine (TETA) or 2,6-diaminopyridine (DAP), followed by palladium nanoparticles (Pd NPs) for the synthesis of Pd NPs/GO-TETA and Pd NPs/GO-DAP nanocomposites, respectively. The two heterogeneous nanocomposites were fully characterized and their efficiency was investigated for C[sbnd]C bond formation for the synthesis of biaryl compounds via the Suzuki cross-coupling reaction of aryl halides with arylboronic acid derivatives. The obtained results indicated that the Pd NPs/GO-TETA nanocomposite was more effective in the Suzuki coupling reaction as compared to Pd NPs/GO-DAP. Thus, the Suzuki cross-coupling reaction of different aryl halides with arylboronic acid derivatives using Pd NPs/GO-TETA nanocomposite catalyst in the presence of Na2CO3 as base in DMF/H2O (1/1) as solvent at 90 °C was carried out to afford the desired biaryl compounds in high to excellent yields (81–100%) and short reaction times (10–90 min). Additionally, Pd NPs/GO-TETA nanocomposite can be recovered and reused for 8 consecutive runs without any apparent loss of its catalytic activity, proving its high stability and potential use in organic transformations.
- Boukherroub, Rabah,Mirza-Aghayan, Maryam,Mohammadi, Marzieh
-
-
- Face-Directed Tetrahedral Organic Cage Anchored Palladium Nanoparticles for Selective Homocoupling Reactions
-
Numerous metalla-supramolecular architectures have been designed using coordination-driven self-assembly, while the number of analogous organic architectures is still very limited. In this regard, mainly di-, tri- and a few tetra-aldehydes have been exploited as precursors in combination with appropriate di-/tri-amines to obtain the desired structures with limited complexities. We report here facile synthesis of two face-directed tetrahedral organic cages (TC-R and TC-S) that were formed by [4+12] imine condensation of a new hexa-aldehyde precursor with two enantiomers of 1,2-diaminocyclohexane separately (CA-R and CA-S). The covalent imine cages are very large with an intrinsic porous cavity of ~1250 ?3 and the faces of the cages consist of aromatic aldehyde units whereas each corner is occupied by three semi-flexible diamine moieties. Palladium (PdNPs) nanoparticles (3.5±0.3 nm) were synthesized employing the cage TC-R as a solid support via double-solvent approach. Furthermore, the cage hosted PdNPs [Pd(0)@TC-R-A] exhibited efficient catalytic activity for selective homocoupling of aryl- and hetero-aryl halides with high thermal stability and reusability.
- Bhandari, Pallab,Mondal, Bijnaneswar,Howlader, Prodip,Mukherjee, Partha Sarathi
-
-
- Suzuki-Miyaura Cross-Coupling Reaction with Potassium Aryltrifluoroborate in Pure Water Using Recyclable Nanoparticle Catalyst
-
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
-
-
- Palladium-catalyzed aryl group transfer from triarylphosphines to arylboronic acids
-
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.
-
-
- Visible Light Induced Aerobic Coupling of Arylboronic Acids Promoted by Hydrazone
-
A visible-light-induced oxidative coupling of arylboronic acids has been developed for the synthesis of biaryls. The reaction that employs polydentate hydrazones as the bifunctional catalyst works smoothly under room temperature. It is compatible with a w
- Xia, Hongyu,Wang, Ganghu,Zhao, Dongbo,Zhu, Chunyin
-
supporting information
p. 922 - 929
(2022/02/10)
-
- Nickel- and Palladium-Catalyzed Cross-Coupling of Stibines with Organic Halides: Site-Selective Sequential Reactions with Polyhalogenated Arenes
-
Herein, we disclose a general and efficient method for the synthesis of Sb-aryl and Sb-alkyl stibines by the nickel-catalyzed cross-coupling of halostibines with organic halides. The synthesized Sb-aryl stibines couple with aryl halides to give biaryls efficiently via palladium catalysis. Sequential reactions of stibines with polyhalogenated arenes bearing active C–I/C–Br sites and inactive C–Cl sites successfully proceeded, resulting in the formation of a variety of complex molecules with good site selectivity. Drugs such as diflunisal and fenbufen, as well as a fenofibrate derivative, were synthesized on gram scales in good yields, together with the high recovery of chlorostibine. Furthermore, catalytic mechanisms are proposed based on the results of control experiments.
- Ghaderi, Arash,Kambe, Nobuaki,Le, Liyuan,Lu, Hao,Qiu, Renhua,Tang, Ting,Tong, Zhou,Wong, Wai-Yeung,Xu, Zhi,Yin, Shuang-Feng,Zeng, Dishu,Zhang, Dejiang,Zhang, Zhao
-
p. 854 - 867
(2022/01/19)
-
- Pd-Catalyzed desulfitative arylation of olefins by: N -methoxysulfonamide
-
A novel Pd-catalyzed protocol for the desulfitative Heck-type reaction of N-methoxy aryl sulfonamides with alkenes was reported. The cross-coupling reaction was performed successfully with a variety of olefins to obtain aryl alkenes. Different substituents on the aromatic ring of N-methoxysulfonamides were also found to be compatible with the reaction conditions. Expectedly, the reaction proceeds through CuCl2-promoted generation of the nitrogen radical and subsequent desulfonylation under thermal conditions to afford the aryl radical for the Pd-catalyzed coupling reaction. N-Methoxysulfonamide was further exploited for the synthesis of symmetrical biaryls in the presence of CuCl2. This journal is
- Ojha, Subhadra,Panda, Niranjan
-
supporting information
p. 1292 - 1298
(2022/02/19)
-
- Magnetic chitosan-functionalized cobalt-NHC: Synthesis, characterization and catalytic activity toward Suzuki and Sonogashira cross-coupling reactions of aryl chlorides
-
Aryl chlorides are one of the most stable and available electrophiles, however, their coupling with nucleophiles remains a challenge in organic synthesis. Herein, we prepared a Cobalt-NHC (N-Heterocyclic carbene) complex anchored on magnetic chitosan nanoparticles and assayed its catalytic activity for the reactions of substituted phenylboronic acid and also phenlacetylene with derivatives of aryl chlorides. These reactions are of great importance since they are employed for the synthesis of unsymmetrical diarylethynes and biphenyls, which belong to a prime class of building blocks. The synthesized nanocatalyst was found to be highly efficient in Suzuki and Sonogashira coupling in terms of their activity and recyclability in polyethylene glycol (PEG) as a green reaction media under conditions of temperatures (70 and 100 °C) and Co loading (3 and 6 mol%). To the best of our knowledge, this is the first attempt of using cobalt-NHC complex for catalyzing the abovementioned reactions. Moreover, replacing the earth-abundant Cobalt-based catalyst as an alternative to high cost palladium make this approach promising from sustainable chemistry view.
- Hajipour, Abdol R.,Malek, Shaghayegh Sadeghi
-
-
- Anchored Pd(0) Nanoparticles on Synthetic Talc for the Synthesis of Biaryls and a Precursor of Angiotensin II Inhibitors
-
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.
-
p. 933 - 942
(2020/12/28)
-
- Heterogeneous Fe3O4@Si–NHC–Pd Catalyst: Synthesis, Characterization, and Catalytic Activity in the Suzuki–Miyaura Cross-Coupling Reaction under Mild Conditions
-
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.
-
p. 1140 - 1146
(2021/08/06)
-
- Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
-
Heterogeneous homocoupling reactions of phenylboronic acids were greatly accelerated via Suzuki homocoupling reactions. In this work, a tandem route was designed which firstly one part of phenylboronic acids reacted with iodine to form iodobenzenes, then another part of phenylboronic acids coupled with iodobenzenes to produce biaryl compounds. The tandem reaction were catalyzed by a bifunctional heterogeneous catalyst of metal organic frameworks encapsulated with palladium nanoparticles (Pd?MOFs). This strategy for forming symmetric C-C bond between benzene rings has obvious advantages such as high efficiency, easy separation, good recyclability and no addition of toxic halogenated benzene.
- Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
-
-
- Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate
-
Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C?C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C?C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.
- Uzelac, Marina,Mastropierro, Pasquale,de Tullio, Marco,Borilovic, Ivana,Tarrés, Màrius,Kennedy, Alan R.,Aromí, Guillem,Hevia, Eva
-
supporting information
p. 3247 - 3253
(2020/12/11)
-
- Electrochemical coupling halobenzene into biphenyl on a reusable Pd nanoparticle-coated carbon-paper electrode at ambient conditions
-
Electrochemical organic synthesis (EOS) employing electrons to directly activate the reactants can readily complete the chemical conversion under mild conditions. Here, it presented an efficient electrochemical coupling halobenzene into biphenyl on a Pd nanoparticle-coated cathode. The biphenyl product can be obtained with a yield up to 77% at 35 mA, 6 h (3.9 F mol?1). In addition, after consecutive fifth run of the coupling reaction, the yield still remained atca.40%, suggesting its considerable recyclable capacity. In addition, the preliminary kinetics studyviathe off-line gas chromatography analysis of the reaction mixture shows a two-section reaction process, including the introduction process (IP) and fast conversion process (FCP). Further, the estimated reaction kinetics constant value of 0.196 min?1for FCP suggests a more effective conversion than that obtained by the previous study. This study adopts a simple way to fabricate a low-cost and reusable Pd electrode, achieving a high-efficiency electrochemical strategy for the Ullmann-type coupling reaction at mild conditions, and holds a great promise to extend this synthesis route to other important organic synthesis.
- Wang, Chao-Nan,Lu, Yong-Heng,Liu, Yue,Liu, Jun,Yang, Yao-Yue,Zhao, Zhi-Gang
-
p. 3997 - 4003
(2021/03/06)
-
- Reductive Coupling of Aryl Halides via C—H Activation of Indene
-
This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
- Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
-
p. 1573 - 1579
(2021/05/28)
-
- Zirconium-redox-shuttled cross-electrophile coupling of aromatic and heteroaromatic halides
-
Transition metal-catalyzed cross-electrophile coupling (XEC) is a powerful tool for forging C(sp2)–C(sp2) bonds in biaryl molecules from abundant aromatic halides. While the synthesis of unsymmetrical biaryl compounds through multimetallic XEC is of high synthetic value, the selective XEC of two heteroaromatic halides remains elusive and challenging. Herein, we report a homogeneous XEC method, which relies on a zirconaaziridine complex as a shuttle for dual palladium-catalyzed processes. The zirconaaziridine-mediated palladium (ZAPd)-catalyzed reaction shows excellent compatibility with various functional groups and diverse heteroaromatic scaffolds. In accord with density functional theory (DFT) calculations, a redox transmetallation between the oxidative addition product and the zirconaaziridine is proposed as the crucial elementary step. Thus, cross-coupling selectivity using a single transition metal catalyst is controlled by the relative rate of oxidative addition of Pd(0) into the aromatic halide. Overall, the concept of a combined reducing and transmetallating agent offers opportunities for the development of transition metal reductive coupling catalysis.
- Fu, Yue,Liu, Fang-Jie,Liu, Peng,Tang, Jian-Tao,Toste, F. Dean,Wu, Ting-Feng,Ye, Baihua,Zhang, Yue-Jiao
-
supporting information
p. 1963 - 1974
(2021/07/07)
-
- Ultrafine and Highly Dispersed Pd/SiO2 for Suzuki?Miyaura Cross-coupling Reactions
-
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
-
p. 2291 - 2301
(2021/01/04)
-
- Preparation of metal-immobilized methacrylate-based monolithic columns for flow-through cross-coupling reactions
-
With the aim of developing efficient flow-through microreactors for high-throughput organic synthesis, in this work, microreactors were fabricated by chemically immobilizing palladium-, nickel-, iron-, and copper-based catalysts onto ligand-modified poly(glycidyl methacrylate-co-ethylene dimethacrylate) [poly(GMA-co-EDMA)] monoliths, which were prepared inside a silicosteel tubing (10 cm long with an inner diameter of 1.0 mm) and modified with several ligands including 5-amino-1,10-phenanthroline (APHEN), iminodiacetic acid (IDA), and iminodimethyl phosphonic acid (IDP). The performance of the resulting microreactors in Suzuki?Miyaura cross-coupling reactions was evaluated, finding that the poly(GMA-co-EDMA) monolith chemically modified with 5-amino-1,10-phenanthroline as a binding site for the palladium catalyst provided an excellent flow-through performance, enabling highly efficient and rapid reactions with high product yields. Moreover, this monolithic microreactor maintained its good activity and efficiency during prolonged use.
- Sabarudin, Akhmad,Shu, Shin,Yamamoto, Kazuhiro,Umemura, Tomonari
-
-
- A recyclable self-supported nanoporous PdCu heterogeneous catalyst for aqueous Suzuki-Miyaura cross-coupling
-
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
-
supporting information
p. 11641 - 11644
(2021/11/12)
-
- Rapid gram-scale synthesis of Au/chitosan nanoparticles catalysts using solid mortar grinding
-
Owing to the abundant functional groups present in the chitosan polymer, high density catalytic tiny gold particles with greater dispersion can be anchored on the chitosan powder using simple mortar and pestle. Chitosan-supported gold nanoparticles (NPs) with excellent control of size and shape were rapidly synthesized in gram-scale by solid-grinding without the need of any toxic solvents. The structure of catalysts and products was established by advanced instrumental and spectroscopic methods. The supported gold NPs functions as a heterogeneous catalyst for the homocoupling of phenylboronic acid and the aerobic oxidation of benzyl alcohol in water. The catalytic behaviour and activity of supported gold NPs was tuned/modulated by varying the ratio of chitosan polymer and gold precursor. Comparative studies showed that the solid chitosan supported gold catalyst exhibits superior catalytic activity and selectivity than the well known hydrophilic polymer-stabilized gold NPs catalysts prepared by the conventional solution-based methods.
- Reddy, K. Paul,Meerakrishna,Shanmugam,Satpati, Biswarup,Murugadoss
-
p. 438 - 446
(2021/01/11)
-
- Sustainable Synthesis of Biaryls Using Silica Supported Ferrocene Appended N-Heterocyclic Carbene-Palladium Complex
-
Abstract: A novel silica supported ferrocene appended N-heterocyclic carbene-palladium complex (SilFemBenzNHC@Pd) has been prepared and characterized by using fourier transform infrared (FT-IR), fourier transform Raman (FT-Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive X-ray analysis (EDX). This novel complex served as a robust heterogeneous catalyst for the synthesis of biaryls via homocoupling of aryl boronic acids under base-free conditions in water. Recyclability experiments were executed successfully for six successive runs. Graphic Abstract: [Figure not available: see fulltext.]
- Khanapure, Sharanabasappa,Pore, Dattaprasad,Jagadale, Megha,Patil, Vaishali,Rashinkar, Gajanan
-
p. 2237 - 2249
(2021/01/11)
-
- Pd-catalyzed oxidative homocoupling of arylboronic acids in WEPA: A sustainable access to symmetrical biaryls under added base and ligand-free ambient conditions
-
Symmetrical and unsymmetrical biaryls comprises a diverse class of biologically eloquent organic compounds. We herein report, a quick and eco-friendly protocol for the synthesis of biaryls by an oxidative (aerobic) homocoupling of arylboronic acids (ABAs) using Pd(OAc)2 in water extract of pomogranate ash (WEPA) as an efficient agro-waste(bio)-derived aqueous (basic) media. The reactions were executed at ambient aerobic conditions in the absence of external base and ligand to result symmetrical biaryls in excellent yields. The use of renewable media with an effective exploitation of waste, short reaction times, excellent yields of products, easy separation of the products, unnecessating the external base, oxidant, ligand or volatile organic solvents and ambient reaction conditions are the vital insights of the present protocol.
- Appa, Rama Moorthy,Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Venkateswarlu, Katta
-
-
- Nickel- and Palladium-Catalyzed Cross-Coupling Reactions of Organostibines with Organoboronic Acids
-
A strategy for the formation of antimony-carbon bond was developed by nickel-catalyzed cross-coupling of halostibines. This method has been applied to the synthesis of various triaryl- and diarylalkylstibines from the corresponding cyclic and acyclic halostibines. This protocol showed a wide substrate scope (72 examples) and was compatible to a wide range of functional groups such as aldehyde, ketone, alkene, alkyne, haloarenes (F, Cl, Br, I), and heteroarenes. A successful synthesis of arylated stibine 3 a in a scale of 34.77 g demonstrates high synthetic potential of this transformation. The formed stibines (R3Sb) were then used for the palladium-catalyzed carbon–carbon bond forming reaction with aryl boronic acids [R?B(OH)2], giving biaryls with high selectivity, even the structures of two organomoieties (R and R′) are very similar. Plausible catalytic pathways were proposed based on control experiments.
- Zhang, Dejiang,Le, Liyuan,Qiu, Renhua,Wong, Wai-Yeung,Kambe, Nobuaki
-
supporting information
p. 3104 - 3114
(2020/12/11)
-
- "benchtop" Biaryl Coupling Using Pd/Cu Cocatalysis: Application to the Synthesis of Conjugated Polymers
-
Typically, Suzuki couplings used in polymerizations are performed at raised temperatures in inert atmospheres. As a result, the synthesis of aromatic materials that utilize this chemistry often demands expensive and specialized equipment on an industrial scale. Herein, we describe a bimetallic methodology that exploits the distinct reactivities of palladium and copper to perform high yielding aryl-aryl dimerizations and polymerizations that can be performed on a benchtop under ambient conditions. These couplings are facile and can be performed by simple mixing in the open vessel. To demonstrate the utility of this method in the context of polymer synthesis: polyfluorene, polycarbazole, polysilafluorene, and poly(6,12-dihydro-dithienoindacenodithiophene) were created at ambient temperature and open to air.
- Minus, Matthew B.,Moor, Sarah R.,Pary, Fathima F.,Nirmani,Chwatko, Malgorzata,Okeke, Brandon,Singleton, Josh E.,Nelson, Toby L.,Lynd, Nathaniel A.,Anslyn, Eric V.
-
supporting information
p. 2873 - 2877
(2021/05/05)
-
- Porphyrin n-pincer pd(Ii)-complexes in water: A base-free and nature-inspired protocol for the oxidative self-coupling of potassium aryltrifluoroborates in open-air
-
Metalloporphyrins (and porphyrins) are well known as pigments of life in nature, since representatives of this group include chlorophylls (Mg-porphyrins) and heme (Fe-porphyrins). Hence, the construction of chemistry based on these substances can be based on the imitation of biological systems. Inspired by nature, in this article we present the preparation of five different porphyrin, meso-tetraphenylporphyrin (TPP), meso-tetra(p-anisyl)porphyrin (TpAP), tetra-sodium meso-tetra(p-sulfonatophenyl)porphyrin (TSTpSPP), meso-tetra(m-hydroxyphenyl)porphyrin (TmHPP), and meso-tetra(m-carboxyphenyl)porphyrin (TmCPP) as well as their N-pincer Pd(II)-complexes such as Pd(II)-meso-tetraphenylporphyrin (PdTPP), Pd(II)-meso-tetra(p-anisyl)porphyrin (PdTpAP), Pd(II)-tetrasodium meso-tetra(p-sulfonatophenyl)porphyrin (PdTSTpSPP), Pd(II)-meso-tetra(m-hydroxyphenyl)porphyrin (PdTmHPP), and Pd(II)-meso-tetra(m-carboxyphenyl)porphyrin (PdTmCPP). These porphyrin N-pincer Pd(II)-complexes were studied and found to be effective in the base-free self-coupling reactions of potassium aryltrifluoroborates (PATFBs) in water at ambient conditions. The catalysts and the products (symmetrical biaryls) were characterized using their spectral data. The high yields of the biaryls, the bio-mimicking conditions, good substrate feasibility, evading the use of base, easy preparation and handling of catalysts, and the application of aqueous media, all make this protocol very attractive from a sustainability and cost-effective standpoint.
- Hanafiah, Marlia M.,Lakkaboyana, Sivarama Krishna,Lakshmidevi, Jangam,Marella, Ravi Kumar,Naidu, Bandameeda Ramesh,Prasad, Sana Siva,Venkateswarlu, Katta
-
-
- Recyclable Pd2dba3/XPhos/PEG-2000 System for Efficient Borylation of Aryl Chlorides: Practical Access to Aryl Boronates
-
Pd2dba3/XPhos in poly(ethylene glycol) (PEG-2000) is shown to be a highly stable and efficient catalyst for the borylation of aryl chlorides with bis(pinacolato)diboron. The borylation reaction proceeds smoothly at 110 °C, delivering a wide variety of aryl boronates in good to excellent yields with high functional group tolerance. The crude products were easily isolated via simple extraction of the reaction mixture with cyclohexane. Moreover, both expensive Pd2dba3 and XPhos in PEG-2000 system could be readily recycled and reused more than six times without loss of catalytic efficiency.
- Cai, Mingzhong,Huang, Bin,Luo, Chengkai,Xu, Caifeng
-
-
- Mixed Alkyl/Aryl Diphos Ligands for Iron-Catalyzed Negishi and Kumada Cross Coupling Towards the Synthesis of Diarylmethane
-
Mixed alkyl/aryl diphos ligands have been prepared and their application in iron-catalyzed cross coupling of benzylic chlorides with diaryl zinc (Negishi) or aryl Grignard reagents (Kumada) towards the synthesis of diarylmethane has been evaluated. The iron?diphos catalytic system exhibited the enhanced activity and selectivity in the two coupling reactions. The electron-rich mixed PPh2/PCy2 ligands outperformed their symmetrical PPh2 congeners, and led to decreased homocoupling byproduct formation. It indicates that the electronic effect of the ligands plays an important role in the catalytic performance. The Fe catalyst supported by L8 bearing an electron-rich PCy2 substituent and a sterically demanding tert-butyl on ethene backbone exhibited the best catalytic performance and good functional group tolerance in the two cross coupling reactions.
- Ma, Xufeng,Wang, Han,Liu, Yao,Zhao, Xing,Zhang, Jun
-
p. 5134 - 5140
(2021/11/16)
-
- Structural and catalytic properties of the [Ni(BIPHEP)X2] complexes, BIPHEP = 2,2-diphenylphosphino-1,1-biphenyl; X = Cl, Br
-
The synthesis and catalytic properties in Kumada C–C coupling of the [Ni(BIPHEP)X2] complexes, X = Cl (1), Br (2), are described. The crystal structures of the BIPHEP ligand and 2 are also presented and compared with previously reported crystal structures of atropisomeric bidentate phosphine ligands (P,P) and related [M(P,P)X2] complexes (M = Ni, Pd, Pt). BIPHEP crystallizes in the C2/c space group, with both enantiomers present in the unit cell. This is consistent with BIPHEP being a “tropos” ligand. Complex 2 crystallizes in the P21/a space group. There are two symmetry-independent molecules in the asymmetric unit, namely 2a and 2b, in which the BIPHEP ligand adopts the S or the R configuration, respectively. Complexes 2a and 2b exhibit a severely tetrahedrally-distorted square planar NiP2Br2 coordination sphere, with a PNiP bite angle of 93.3° and 94.7°, respectively. The observed catalytic behavior of complexes 1 and 2 in the Kumada coupling between p-tert-butyl-halogenobenzene and p-tolylmagnesium chloride is benchmarked against that of [Ni(dppp)Cl2], dppp = 1,3-bis(diphenylphoshpino)propane. However, all three complexes are catalytically inactive in the Suzuki-Miyaura coupling reaction.
- Ioannou, Polydoros-Chrysovalantis,Grigoropoulos, Alexios,Stergiou, Konstantina,Raptopoulou, Catherine P.,Psycharis, Vassilis,Svoboda, Jan,Kyritsis, Panayotis,Vohlídal, Ji?í
-
-
- Strategy for Selective Csp2-F and Csp2-Csp2Formations from Organoplatinum Complexes
-
By changing the parameters of fluorination reaction of bisaryl-platinum(II) complexes, each possible competitive pathway of Ar-Ar and Ar-F formation can be selectively controlled. It was discovered that steric hindrance, type of fluorinating reagent, and
- Sarkissian, Elin,Golbon Haghighi, Mohsen
-
supporting information
p. 1016 - 1020
(2021/02/05)
-
- Arylation ofgem-difluoroalkenes using a Pd/Cu Co-catalytic system that avoids β-fluoride elimination
-
PdII/CuIco-catalyze an arylation reaction ofgem-difluoroalkenes using arylsulfonyl chlorides to deliver α,α-difluorobenzyl products. The reaction proceeds through a β,β-difluoroalkyl-Pd intermediate that typically undergoes unimolecular β-F elimination to deliver monofluorinated alkene products in a net C-F functionalization reaction. However to avoid β-F elimination, we offer the β,β-difluoroalkyl-Pd intermediate an alternate low-energy route involving β-H elimination to ultimately deliver difluorinated products in a net arylation/isomerization sequence. Overall, this reaction enables exploration of new reactivities of unstable fluorinated alkyl-metal species, while also providing new opportunities for transforming readily available fluorinated alkenes into more elaborate substructures.
- Yuan, Kedong,Feoktistova, Taisiia,Cheong, Paul Ha-Yeon,Altman, Ryan A.
-
p. 1363 - 1367
(2021/02/12)
-
- Pd-NHCs Enabled Suzuki-Miyaura Cross-Coupling of Arylhydrazines via C–N Bond Cleavage
-
We describe a highly efficient protocol for cross-coupling of phenylhydrazines with arylboronic acids by Pd-NHCs under aerobic reaction condition. A series of well-defined Pd-NHCs complexes were evaluated and the relationship between the structure and the catalytic properties was investigated. It was disclosed that the Pd-PEPPSI-IPr proved to be the robust precatalyst, providing access to a range of (hetero)biaryls in good to excellent yields.
- Zeng, Xiao-Xiao,Li, Dong-Hui,Zhou, Zhen,Xu, Chang,Liu, Feng-Shou
-
supporting information
(2021/03/01)
-
- Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
-
Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
- Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
-
p. 2084 - 2092
(2021/04/02)
-
- Synchronized C?H activations at proximate dinuclear Pd2+ sites on silicotungstate for oxidative C?C coupling
-
Carbon?carbon (C?C) coupling is critically important in organic synthesis. Direct C?C coupling to replace two C?H bonds is preferred over coupling of two prefunctionalized C?intermediates but is synthetically challenging. While such coupling is feasible through homogeneous catalysis, the mechanism regarding how the two C?H bonds are activated and coupled by heterogeneous active metal atoms remains not well understood. This work demonstrates the need for a proximate metal?metal dimer site to facilitate heterogeneously catalyzed C?C coupling reactions. We demonstrate that dinuclear Pd2+ sites in (Pd2+)2-silicotungstate (Pd2ST) catalyzed oxidative C?C coupling of 2-methylfuran by O2 through synchronized double C?H activations under ambient conditions, selectively producing 5,5′-dimethyl-2,2′-bifuran (DMBF). Mononuclear Pd2+ ions in Pd H ST and H ST are not active. The 13C NMR and DRIFT spectroscopies of adsorbed 13CO, combined with DFT and theoretical 13C NMR calculations, determined that dinuclear Pd2+ ions are separated by ~3.5 ? on Pd2ST and 3.1 ? in the Pd2+-C(=O)-Pd2+ complex. XRD and TEM are used to confirm that the most active Pd2ST/SiO2 catalyst has near monolayer dispersion. 29Si MAS NMR is used to confirm the presence of the silicotungstate structure after calcination. The original silicotungstate Keggin structure is maintained after the Pd2ST/SiO2 is calcined.
- Ramineni, Kishore,Liu, Kairui,Zhang, Cheng,Chen, Xuke,Hou, Guangjin,Gao, Pan,Balaga, Ravi,Marri, Mahender Reddy,Yan, Peifang,Guan, Xian,Xia, Zhi,Janik, Michael J.,Zhang, Z. Conrad
-
p. 3455 - 3465
(2021/04/09)
-
- Redox Activity of Pyridine-Oxazoline Ligands in the Stabilization of Low-Valent Organonickel Radical Complexes
-
Low-valent organonickel radical complexes are common intermediates in cross-coupling reactions and metalloenzyme-mediated processes. The electronic structures of N-ligand supported nickel complexes appear to vary depending on the actor ligands and the coordination number. The reduction products of a series of divalent (pyrox)Ni complexes establish the redox activity of pyrox in stabilizing electron-rich Ni(II)-alkyl and -aryl complexes by adopting a ligand-centered radical configuration. The reduced pyrox imparts an enhanced trans-influence. In contrast, such redox activity was not observed in a (pyrox)Ni(I)-bromide species. The excellent capability of pyrox in stabilizing electron-rich Ni species resonates with its proclivity in promoting the reductive activation of C(sp3) electrophiles in cross-coupling reactions.
- Wagner, Clifton L.,Herrera, Gabriel,Lin, Qiao,Hu, Chunhua T.,Diao, Tianning
-
supporting information
p. 5295 - 5300
(2021/05/04)
-
- Relevance of Single-Transmetalated Resting States in Iron-Mediated Cross-Couplings: Unexpected Role of σ-Donating Additives
-
Control of the transmetalation degree of organoiron(II) species is a critical parameter in numerous Fe-catalyzed cross-couplings to ensure the success of the process. In this report, we however demonstrate that the selective formation of a monotransmetalated FeII species during the catalytic regime counterintuitively does not alone ensure an efficient suppression of the nucleophile homocoupling side reaction. It is conversely shown that a fine control of the transmetalation degree of the transient FeIII intermediates obtained after the activation of alkyl electrophiles by a single-electron transfer (SET), achievable using σ-donating additives, accounts for the selectivity of the cross-coupling pathway. This report shows for the first time that both coordination spheres of FeII resting states and FeIII short-lived intermediates must be efficiently tuned during the catalytic regime to ensure high coupling selectivities.
- Rousseau, Lidie,Touati, Nadia,Binet, Laurent,Thuéry, Pierre,Lefèvre, Guillaume
-
p. 7991 - 7997
(2021/05/26)
-
- Rhenium-Catalyzed Arylation–Acyl Cyclization between Enol Lactones and Organomagnesium Halides: Facile Synthesis of Indenones
-
A set of rhenium-catalyzed arylation–acyl cyclizations between (hetero)arylmagnesium halides and enol lactones through a cascade C(sp2)?C(sp2)/C(sp2)?C(sp2) bond formation under mild reaction conditions has been developed. Indeed, a wide range of functional groups on both organomagnesium halides and enol lactones is well tolerated by the simple rhenium catalysis, thus furnishing polyfunctionalized indenones in one-pot fashion and with complete control of the regioselectivity. Moreover, this approach also provides a straightforward synthetic route to neolignan and (iso)pauciflorol F. Mechanistic studies demonstrated that the reaction involves a sequence of syn-carborhenation and intramolecular nucleophilic addition.
- Cheng, Xinyi,Hu, Binjing,Hu, Ying,Karaghiosoff, Konstantin,Li, Jie,Liu, Xingchen
-
supporting information
p. 15497 - 15502
(2021/06/11)
-
- Palladium-catalyzed denitrogenative cross-coupling of aryl halides with arylhydrazines under mild reaction conditions
-
A greener approach for the synthesis of various functionalized biaryl frameworks in good to excellent yield through palladium-catalyzed denitrogenative cross-coupling of aryl halides with arylhydrazines under mild reaction conditions was developed. Catalytic system is free from the aid of expensive ligands and external oxidants. Biogenically prepared palladium nanoparticles (Pd NPs) immobilized cellulose based dip catalyst displayed excellent reactivity and selectivity toward the synthesis of a broad array of symmetrical and unsymmetrical biaryls through C–N bond cleavage in air as green oxidant. In addition, recyclability in denitrogenative cross-coupling reaction was also studied which showed excellent recycling performance and the dip catalyst remained stable even after several reuses. Thus, our newly developed strategy was successfully applied for constructing wide-ranging functional groups tolerated biaryls using arylhydrazines and aryl halides as coupling partners which is most useful for practical applications in synthetic chemistry.
- Kempasiddaiah, Manjunatha,Kandathil, Vishal,Dateer, Ramesh B.,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
-
p. 273 - 281
(2021/01/12)
-
- The Anionic Pathway in the Nickel-Catalysed Cross-Coupling of Aryl Ethers
-
The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C?C and C?heteroatom bonds. However, the inert C(sp2)?O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.
- Borys, Andryj M.,Hevia, Eva
-
supporting information
p. 24659 - 24667
(2021/10/20)
-
- Grignard reagent dictated copper(I) phosphines catalyzed reductive coupling of diazo compounds: The chemistry beyond carbene generation
-
Copper-dppf catalyzed reductive coupling of diazo compounds through terminal nitrogen is reported. However, copper catalysts are known to produce carbene from diazo compounds; the reaction conditions played an important role in the formation of diazine over carbene generation. Several control experiments have been conducted to understand the reaction mechanism and found that the formation of a copper–Mg heterobimetallic complex would be responsible for the observed reactivity pattern. The reaction produced diazine as a reductive coupling product along with biphenyl as a by-product. All the synthesized diazines have been characterized fully by using analytical and spectroscopic techniques.
- Kuzhalmozhi Madarasi, Packirisamy,Sivasankar, Chinnappan
-
-
- Precursors: Synthesis, Reactivity, and Catalytic Application to the Suzuki-Miyaura Reaction
-
The complexes (Cy2PC3H6PCy2)Ni(η2-arene) (arene = toluene (3), naphthalene (4)) have been synthesized and studied in detail. Displacement reactions of the toluene ligand afford the complexes (Cy2PC3H6PCy2)Ni(η2-styrene) (5), (Cy2PC3H6PCy2)Ni(PhCN) (6), (Cy2PC3H6PCy2)Ni(CO)2 (7), (Cy2PC3H6PCy2)Ni(PPh3) (8), (Cy2PC3H6PCy2)Ni(PCy3) (9), {(Cy2PC3H6PCy2)Ni}2(μ-H)2 (10), (Cy2PC3H6PCy2)Ni(η2-CO2) (11), and [(Cy2PC3H6PCy2)Ni]2(μ,η2-1,5-COD) (12). The relative rates of ArCl oxidative addition at Ni complexes 3, 4, 6, 8, and 12 have been evaluated experimentally, and the mechanism has been calculated by DFT. Complexes 3 and 4 are efficient catalysts for the Suzuki-Miyaura reaction between chloroarenes and Ar′B(OH)2.
- D'Accriscio, Florian,Ohleier, Alexia,Nicolas, Emmanuel,Demange, Matthieu,Thillaye Du Boullay, Olivier,Saffon-Merceron, Nathalie,Fustier-Boutignon, Marie,Rezabal, Elixabete,Frison, Gilles,Nebra, Noel,Mézailles, Nicolas
-
supporting information
p. 1688 - 1699
(2020/06/04)
-
- Activator-Promoted Aryl Halide-Dependent Chemoselective Buchwald-Hartwig and Suzuki-Miyaura Type Cross-Coupling Reactions
-
Herein, we report the development of aryl halide-dependent chemoselective reactions, viz., the Buchwald-Hartwig type coupling reaction of an aryl iodide with an arylboronic acid and an aryl amine in the presence of a heterogeneous and reusable nickel catalyst and the Suzuki-Miyaura type coupling of an aryl chloride under similar conditions. Control experiments revealed that the presence of stoichiometric amounts of the phenylboronic acid/ester and aryl amine are essential for both reactions. NMR and XAFS studies suggested the formation of a boron-amine "ate"complex.
- Dhital, Raghu N.,Hashizume, Daisuke,Hu, Hao,Ishii, Rikako,Sato, Takuma,Sen, Abhijit,Takaya, Hikaru,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
-
supporting information
(2020/06/29)
-
- Synthesis of palladated magnetic nanoparticle (Pd@Fe3O4/AMOCAA) as an efficient and heterogeneous catalyst for promoting Suzuki and Sonogashira cross-coupling reactions
-
Palladium supported magnetic nanoparticle (Pd@Fe3O4/AMOCAA) was easily prepared in the presence of Scrophularia striata extract and fully characterized by FT-IR, SEM, VSM, TEM, TGA, XRD and EDAX. It was successfully employed as an easily separable and reusable effective heterogeneous catalyst classical Suzuki and Sonogashira cross-coupling reaction. Sustainability of the methodology was reserved by easy recovery of the catalyst using an external magnet and reusing it for 7 times without appreciable loss of its catalytic activity.
- Tamoradi, Taiebeh,Daraie, Mansoureh,Heravi, Majid M.
-
-
- 4-Amino-1,2,4-triazoles-3-thiones and 1,3,4-oxadiazoles-2-thiones·palladium(II) recoverable complexes as catalysts in the sustainable Suzuki-Miyaura cross-coupling reaction
-
The Suzuki-Miyaura cross-coupling reaction using 4-amino-1,2,4-triazoles and 1,3,4-oxadiazoles-2-thiones·palladium (II) is studied. The reaction is optimized and the most appropriate catalytic complex is tested with several aryl halides, boronic acids in an environmentally benign solvent system (H2O/EtOH). The recovery of the catalytic species is also surveyed because of the nature of the employed solvent. A domino process is efficiently carried out following the standard conditions. Several surface parameters of the ligands are analyzed and the resulting values are extrapolated to the insoluble palladium catalyst.
- Chehrouri, Manel,Moreno-Cabrerizo, Cristina,Othman, Adil A.,Chabour, Ihssene,Ferrándiz-Saperas, Marcos,Sempere, Inmaculada,D?nda?, H. Ali,de Gracia Retamosa,Sansano, José M.
-
-
- Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde polymer as an efficient heterogeneous catalyst for Suzuki–Miyaura coupling reactions
-
This work is described as an environmental friendly approach for Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde-based polymeric material (Cu@MCOP) which has been successfully synthesized by simple approaches using commercially available starting materials via solvothermal techniques and without using any toxic reagents and chemicals. The structural, morphological, physicochemical characteristics and catalytic activity of the heterogeneous catalyst (Cu@MCOP) were analyzed by various instrumental methods including powder X-ray diffraction, FT-IR, UV-DRS, X-ray photoelectron spectroscopy, SEM and elemental mapping which have been used to authenticate the polymeric materials Cu@MCOP. The catalytic performance of Cu@MCOP as solid heterogeneous catalyst was evaluated in synthesis of various biphenyl derivatives through Suzuki–Miyaura cross-coupling reactions of various aryl halides with substituted organoboranes under normal reaction conditions. Furthermore, the copper catalyst was easily available, low cost, cheap and best instead of palladium, which shows good catalytic activity and excellent yield (up to 86%); the catalyst can be separated easily and recycled for more than five times. Graphic abstract: [Figure not available: see fulltext.].
- Sadhasivam, Velu,Sankar, Balakrishnan,Elamathi, Ganesan,Mariyappan, Mathappan,Siva, Ayyanar
-
p. 681 - 700
(2019/11/03)
-
- N-Heterocyclic Carbene–Palladium Complex onto Graphene Oxide and Poly (ethylene glycol) (PEG) Applied as Superior Catalyst for the Suzuki-Miyaura Cross-Coupling Reaction in Water
-
Using polymeric nanocomposites incorporated Pd to promote C-C coupling reactions has been found as one of the most successful strategies. In this paper we apply graphene oxide (GO) as an efficient surface immobilized by water-soluble poly (ethylene glycol)-imidazole followed by introduction of PdCl2 salt to obtain the desired catalyst. Catalytic performance of this composite was investigated in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions and superior results were obtained. The hydrophilic nature of the catalyst and well distribution of Pd lead to superior catalytic activity in water media. Moreover, the Suzuki–Miyaura reaction proceed successfully with excellent yield and short reaction time without any loss of activity even after seven consecutive reaction cycles.
- Heravi, Majid M.,Asadi, Shima,Hoseini Chopani, Seyede Mahdiye,Jaderi, Elham
-
-
- Synthesis, catalytic activity and medium fluorous recycle of fluorous analogues of PEPPSI catalysts
-
PEPPSI complexes are air and moisture stable Pd catalysts, which can be used conveniently in many coupling reactions. With the aim to obtain Pd catalysts recyclable by fluorous separation methods, we modified the structure of commercial PEPPSI complexes by per- or polyfluoroalkylation in various positions. The modifications included the use of a linear polyfluoroalkyl group instead of one aryl group on the NHC ligand, perfluoroalkylation of pyridine ligand, and substitution of chloride ligands on Pd for perfluoroalkanoates or perfluoropolyoxaalkanoates. Comparison of catalytic activity of commercial catalysts with the modified ones in Suzuki-Miyaura cross-coupling reactions showed that the fluorous modifications mostly resulted in the increase of catalytic activity. Moreover, polyfluoroalkylation enabled efficient medium fluorous recycle of the modified catalysts using a two phase aqueous DMF/HFE 7500 ether system.
- ?im?nek, Ond?ej,Rybá?ková, Markéta,Svoboda, Martin,Kví?ala, Jaroslav
-
-
- The synthesis of biphenyl through C-H bond activation in benzene over a Pd catalyst supported on graphene oxide
-
This is the first report on carbon-hydrogen (C-H) bond activation in benzene over a palladium catalyst supported on graphene oxide (GO) leading to the sole formation of biphenyl with a yield of 78%. The reaction was performed for 12 h in the presence of acetic acid and oxygen at 80 °C. XPS studies indicated that in the initial catalyst, Pd is mainly present as Pd(ii) species on the GO surface. The interaction of these species with acetic acid during the reaction generates Pd acetate species. Density functional theory (DFT) studies revealed that the adsorption of the first benzene molecule on the Pd acetate is weak (0.15 eV) and the energy barrier of the following C-H bond scission is high, equal to 1.67 eV. The adsorption of the second benzene molecule is relatively strong (0.40 eV); acetic acid molecules are then released, leaving the biphenyl Pd intermediate, which enables biphenyl molecule formation. The presence of oxygen and acetic acid is needed for closing the catalytic cycle via the regeneration of the reactive Pd acetate.
- Sharma, Deepika,Bulusheva, Lyubov G.,Bulushev, Dmitri A.,Gupta, Neeraj
-
p. 12178 - 12184
(2020/07/30)
-
- para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
-
Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
- Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
-
p. 5058 - 5061
(2020/05/18)
-
- Preparation method of para-substituted aryl compound
-
The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
- -
-
-
- A Bio-Inspired Magnetically Recoverable Palladium Nanocatalyst for the Ullmann Coupling reaction of Aryl halides and Arylboronic acids In Aqueous Media
-
Palladium nanoparticles supported on polydopamine-coated iron oxide nanoparticles (Pd/Fe3O4@PDA) were found to catalyze the Ullmann homocoupling of a wide variety of aryl halides, arylboronic acids and aryldiazonium salts in aqueous media in the presence of randomly methylated β-cyclodextrin (RM-β-CD). The synthesized nanoparticles were characterized by techniques such as TEM, SEM, EDX, XPS, ICP-AES and XRD. The synthesized catalyst can be easily recovered magnetically and reused up to five cycles without any significant loss of activity. This is the first report demonstrating the use of magnetically recoverable catalyst for Ullmann homocoupling reactions of aryl halides, arylboronic acids and aryldiazonium salts in water.
- Dubey, Abhishek V.,Kumar, A. Vijay
-
-