cas 2132-80-1, 4,4'-Dimethoxybiphenyl | Articles data

Articles about 2132-80-1Total 905 be found

Article title
Article abstract
Author
Journal number and time
Download

Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen
It is revealed that N,N′-diphenyl-p-benzoquinonediimine works as a redox-active organocatalyst for the oxidative homo-coupling of aryl- and alkenylmagnesium compounds under molecular oxygen. The catalytic cycle was formally monitored by 1H NMR experiments.
Amaya, Toru,Suzuki, Riyo,Hirao, Toshikazu
p. 7790 - 7793
(2016)
Read Online

Palladium nanoparticle decorated high nitrogen-doped graphene with high catalytic activity for Suzuki–Miyaura and Ullmann-type coupling reactions in aqueous media
Palladium nanoparticle are decorated over a highly nitrogen-doped graphene (Pd NPs-HNG) in a facile manner by reducing palladium chloride in the presence of ethylene glycol as reducing, stabilizing, and dispersing agent. The obtained catalyst can act as an efficient catalyst for the Suzuki–Miyaura and Ullmann-type coupling reactions of a broad spectrum of aryl halides in aqueous media. The remarkable reactivity of the Pd NPs-HNG nanocomposite toward Suzuki–Miyaura and Ullmann-type coupling reactions is attributed to the high degree of nitrogen loading in graphene sheets. The N-doped graphene as polycyclic heteroaromatic molecule acts as both the catalyst support and the electron source (reducing agent) for Ullmann homocoupling. The catalyst could be recovered and reused several times without a significant loss of activity.
Bazgir, Ayoob,Dabiri, Minoo,Movahed, Siyavash Kazemi
p. 265 - 274
(2014)
Read Online

Stable Fe(ii)-based coordination polymers: Synthesis, structural diversity and catalytic applications in homo-coupling reactions
Herein, we synthesize three new stable Fe(ii) coordination polymers, {[Fe3(tttmb)4(OH)(NCS)5]2CH3OH·H2O}n (1), {[Fe3(tttmb)4(NCS)6]·3H2O}n (2), and {[Fe3(tttmb)2Cl6(H2O)6]·5H2O}n (3) (tttmb = 1,3,5-tris(triazole-1-ylmethyl)-2,4,6-trimethyl-benzene) under the regulation of KSCN and solvents and use them as green heterogeneous catalysts in aryl homo-coupling reactions. The catalytic experiments show that 1 and 3 exhibit high efficiency for aryl homo-coupling reactions under an air environment with a yield of up to 80%. Furthermore, the crystal structure analysis reveals that 1 and 3 have coordinated water molecules and OH-, which are easily removed from the host materials during the reactions. In contrast, no unsaturated coordination sites are generated in 2 during the reaction process. In addition, the variable temperature magnetic susceptibilities of 1-3 prove that the metal centers of these polymers are bivalent and all of them exhibit a weak antiferromagnetic effect.
Wu, Qiong,Han, Yanbing,Shao, Zhichao,Li, Junxia,Hou, Hongwei
p. 8063 - 8069
(2018)
Read Online

Vanadium(IV) tetrachloride catalyzed oxidative homo-coupling of aryl lithium under mild reaction condition
A novel efficient strategy to prepare symmetrical diaryls via VCl 4 catalyzed homo-coupling of aryl lithium has been developed. In which, organometallic reagent n-BuLi was applied as the strong base to form aryl lithium from aryl halogen in anhydrous diethyl ether, then it was followed by the addition of catalytic amount of VCl4 at room temperature to afford diaryls. All the diaryls have been characterized by 1H and 13C NMR.
Lu, Feng
p. 2444 - 2446
(2012)
Read Online

A supramolecular peptide nanofiber templated Pd nanocatalyst for efficient Suzuki coupling reactions under aqueous conditions
A bioinspired peptide amphiphile nanofiber template for formation of one-dimensional Pd nanostructures is demonstrated. The Pd and peptide nanocatalyst system enabled efficient catalytic activity in Suzuki coupling reactions in water at room temperature.
Khalily, Mohammad Aref,Ustahuseyin, Oya,Garifullin, Ruslan,Genc, Rukan,Guler, Mustafa O.
p. 11358 - 11360
(2012)
Read Online

Formation and crystallographic elucidation of stable [4 + 2]-coordinate nickel(ii) N,S-heterocyclic carbene (NSHC) complexes
A series of square-planar N,S-heterocyclic carbene (NSHC) complexes trans-[NiX2(N-RBzTh)2] (BzTh = benzothiazolin-2-ylidene) (R/X = Bz/Br; Me/I; Et/I; Pri/I; Bui/I) have been synthesized and characterized by X-ray single-crystal diffraction analysis. These are the first crystallographically established NSHC complexes of nickel in the literature. The N,S-heterocyclic carbene (NSHC) rings invariably twist away from co-planarity with the metal coordination plane such that the N-substituent moves on top and below the metal to facilitate electrostatic γ-hydride interaction, thus giving an essentially [4 + 2] coordination at the Ni(ii) center. These compounds are active toward reductive Ullmann-type coupling reactions in Bu4NBr showing higher activities towards bromoanisole or bromotoluene than bromobenzene. The complex trans-[NiI2(N-Pr iBzTh)2] with the shortest Ni...H anagostic separation and a near-ideal orthogonal orientation between the carbene and metal planes gives the highest yields.
Ding, Nini,Zhang, Jun,Hor, T. S. Andy
p. 1853 - 1858
(2009)
Read Online

Palladium catalyzed the Suzuki cross-coupling reaction using a fluorous NHC ligand
The utilization of N-heterocyclic carbene palladium complex immobilized on fluorous silica gel through fluorous-fluorous interactions in the Suzuki cross-coupling reaction was described. The reactions were carried out under aerobic and phosphine-free conditions with moderate to excellent product yields. The catalyst was easily recovered and reused three times without significant loss of activity.
Wan, Li,Yu, Hong,Cai, Chun
p. 107 - 111
(2012)
Read Online

Palladium-Catalyzed Cross-Coupling Reaction of Lithiated Monocarba- closo -dodecaborate at the Carbon Vertex
A cross-coupling reaction of lithium species of monocarba-closo-dodecaborate {[closo-CHB11H11]-} at the carbon vertex under palladium catalysis was developed. The properties of a metal-carborate complex in a transmetalation step were important to achieve the cross-coupling process with aryl halides, and the use of lithiated monocarba-closo-dodecaborate was found to promote the carbon-carbon bond formation to provide a series of C-arylated monocarba-closo-dodecaborate derivatives. Mechanistic investigations with DFT calculations suggested the efficient transmetalation with the lithium reagent.
Kitazawa, Yu,Otsuka, Mai,Kanazawa, Junichiro,Takita, Ryo,Uchiyama, Masanobu
p. 2403 - 2407
(2015)
Read Online

A new N–heterocyclic carbene palladium complex immobilized on nano silica: An efficient and recyclable catalyst for Suzuki–Miyaura [Formula presented] coupling reaction
A new catalytic system based on Pd–NHC complex utilizing (4–pyridyl)bis(imidazolyl)methane as a bidentate NHC ligand supported on nano?silica is introduced. The catalyst was characterized by FT–IR spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X–ray analysis, transmission electron microscopy and elemental analysis. This heterogeneous catalytic system exhibited excellent activity in the Suzuki–Miyaura coupling reaction of various aryl halides with phenylboronic acid, and was reusable several times without significant loss of its catalytic activity.
Pahlevanneshan, Zari,Moghadam, Majid,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor–Baltork, Iraj,Loghmani-Khouzani, Hossein
p. 31 - 37
(2016)
Read Online

Catalysis by nickel-2,2'-dipyridylamine complexes of the electroreductive coupling of aromatic halides in ethanol
Nickel-2,2'-dipyridylamine complexes are efficient catalysts for achieving in pure ethanol electroreductive dimerisation of aromatic halides or arylation of activated olefins.
Courtois, Valerie,Barhdadi, Rachid,Condon, Sylvie,Troupel, Michel
p. 5993 - 5996
(1999)
Read Online

A series of new mixed-ligand complexes based on 3,6-bis(imidazol-1-yl)pyridazine: Syntheses, structures, and catalytic activities
Seven new mixed-ligand complexes based on L [L = 3,6-bis(imidazol-1-yl)pyridazine], namely, [Ni(L)2(SCN)2]n (1), [Cu5(L)(1,2-BDC)4(μ3-OH)2]n (2), {[Cu4(L)2(1,3-HBDC)(1,3-BDC)(μ3-OH)4]·ClO4·2.6H2O}n (3), {[Ni(L)(1,4-BDC)H2O]·0.25H2O}n (4), [Co(L)(1,3,5-H2BTC)2H2O]n (5), {[Cu2(L)(2,6-PYDC)2(H2O)2]·4.4H2O}n (6), and {[Co(L)(4,4′-OBA)]·3.725H2O}n (7) [1,2-benzenedicarboxylic acid (1,2-H2BDC), 1,3-benzenedicarboxylic acid (1,3-H2BDC), 1,4-benzenedicarboxylic acid (1,4-H2BDC), 1,3,5-benzenetricarboxylic acid (1,3,5-H3BTC), 2,6-pyridine dicarboxylic acid (2,6-H2PYDC), and 4,4′-oxydibenzoic acid (4,4′-H2OBA)], have been synthesized by solvothermal reactions. Complexes 1 and 2 possess a two-dimensional (2D) layered structure, and the 2D framework of complex 1 can be rationalized to be a four-connected {44·62} topological sql network, while 2 exhibits a similar topological network with pentanuclear [Cu5(μ3-OH)2(μ2-COO-)6]2+ secondary building units (SBUs). Complex 3 presents an 8-connected sqc3 3D framework based on a chair-shaped [Cu4(μ3-OH)4]4+ SBU with a Schl?fli symbol of {424·64}. Complex 4 displays a 3D framework with diamondoid topology, which includes L/Ni(ii)/L helical chains. Complex 5 features a 1D chain structure formed by L ligands. Complex 6 shows a dinuclear structure, which is arranged into a 1D supramolecular chain by hydrogen-bonding interactions. The 3D framework of 7 presents a 4-connected porous architecture with a Schl?fli symbol of {66}, the same as that of complex 4. The powder X-ray diffraction spectra, IR spectra, UV-vis absorption spectra and thermal stabilities of 1-7 have been investigated. Moreover, in the complex-catalyzed homocoupling reaction of 4-substituted aryl iodides, the catalytic activities of 1-7 have also been studied and discussed.
Zhou, Sheng-Bin,Wang, Xin-Fang,Du, Ceng-Ceng,Wang, Duo-Zhi,Jia, Dianzeng
p. 3124 - 3137
(2017)
Read Online

Polyhalogenoheterocyclic compounds. Part 54: [1] Suzuki reactions of 2,4,6-tribromo-3,5-difluoropyridine
Palladium catalysed Suzuki cross-coupling reactions between 2,4,6-tribromo-3,5-difluoropyridine and a short series of aromatic boronic acid derivatives gave 4-bromo-3,5-difluoro-2,6-diphenylpyridine derivatives arising from displacement of bromine atoms a
Benmansour, Hadjar,Chambers, Richard D.,Sandford, Graham,Batsanov, Andrei S.,Howard, Judith A.K.
p. 718 - 722
(2007)
Read Online

Di-t-butyl(ferrocenylmethyl)phosphine: Air-stability, structural characterization, coordination chemistry, and application to palladium-catalyzed cross-coupling reactions
Di-t-butyl(ferrocenylmethyl)phosphine (1) has been isolated and structurally characterized. This ligand was found to be reasonably air stable as a solid and it has been shown to possess electron donating ability similar to that of tri-i-propylphosphine. A
Sliger, Michael D.,Broker, Grant A.,Griffin, Scott T.,Rogers, Robin D.,Shaughnessy, Kevin H.
p. 1478 - 1486
(2005)
Read Online

Cu–Fe layered double hydroxide derived mixed metal oxide: Environmentally benign catalyst for Ullmann coupling of aryl halides
Solid mixed metal oxide derived from Cu–Fe-layered double hydroxide by its thermal decomposition at 600?°C has been demonstrated as novel ligand free catalyst for the synthesis of biphenyls through C–C coupling. The catalytic efficiency of this material has been studied by varying the solvents and bases, thereby their influence in controlling the product formation. The C–C coupling yield of aryl halides were found to be higher, when dimethylformamide and potassium carbonate used as a solvent and base respectively. The catalyst can be easily separated from the reaction mixture, simply by filtration and reused several times without significant loss of its activity. The mixed metal oxide has been characterized by XPS, XRD, SEM, BET, TG analysis and the role of calcined Cu–Fe layered double hydroxide in catalyzing C–C coupling reaction was proposed. Moreover, it is ligand-free C–C coupling reaction and is promising alternative than the conventional homogeneous and heterogeneous Pd catalysts.
Dumbre, Deepa,Choudhary, Vasant R.,Selvakannan
p. 180 - 184
(2016)
Read Online

Dinuclear Systems in the Efficient Nickel-Catalyzed Kumada-Tamao-Corriu Cross-Coupling of Aryl Halides
Highly active dinuclear nickel(I) complexes bearing bulky N-heterocyclic carbene ligands have been shown to be involved in the catalytic cycle of the Kumada-Tamao-Corriu cross-coupling reaction of aryl halides. The results of several stoichiometric reactions and kinetics experiments have revealed that monovalent and divalent dinickel species are the active species in the highly efficient, nickel-catalyzed, Kumada coupling reactions of aryl halides.
Matsubara, Kouki,Yamamoto, Hitomi,Miyazaki, Satoshi,Inatomi, Takahiro,Nonaka, Keita,Koga, Yuji,Yamada, Yuji,Veiros, Luis F.,Kirchner, Karl
p. 255 - 265
(2017)
Read Online

The first phosphine oxide ligand precursors for transition metal catalyzed cross-coupling reactions: C-C, C-N, and C-S bond formation on unactivated aryl chlorides
Rapid and regioselective oxidative addition of unactivated aryl chlorides in the presence of bases can be achieved by using metal complexes of phosphinous acid (RR′POH), for which air-stable phosphine oxides (RR′P(O)H) serve as ideal ligand precursors. Such processes can be incorporated into efficient catalytic cycles for a variety of C-C, C-N, and C-S bond-forming processes (see scheme, Ar = aryl).
Li, George Y.
p. 1513 - 1516
(2001)
Read Online

Highly nucleophilic dipropanolamine chelated boron reagents for aryl-transmetallation to iron complexes
New aryl- and heteroarylboronate esters chelated by dipropanolamine are synthesised directly from boronic acids. The corresponding anionic borates are readily accessible by deprotonation and demonstrate an increase in hydrocarbyl nucleophilicity in comparison to other common borates. The new borates proved competent for magnesium or zinc additive-free, direct boron-to-iron hydrocarbyl transmetallations with well-defined iron(ii) (pre)catalysts. The application of the new borate reagents in representative Csp2-Csp3 cross-coupling led to almost exclusive homocoupling unless coupling is performed in the presence of a zinc additive.
Dunsford, Jay J.,Clark, Ewan R.,Ingleson, Michael J.
p. 20577 - 20583
(2015)
Read Online

One-pot, nickel triflate-catalysed homocoupling of aryl chlorides in the presence of metallic magnesium
The homocoupling reaction of aryl chlorides was successfully performed in one-pot without preparation of a Grignard reagent in advance. Various aryl chlorides underwent homocoupling reactions affording the corresponding symmetrical biaryls in moderate to good yields. The nickel triflate catalyst was recovered easily and reused smoothly with only a little loss of its activity.
Lv, Dan,Zhang, Yan-Yan,Li, Jing-Hua
p. 397 - 399
(2009)
Read Online

Imidazole and imidazoline derivatives as N-donor ligands for nickel-catalyzed kumada-tamao-corriu coupling
Imidazole and imidazoline (dihydroimidazole) derivatives can serve as simple and efficient ligands for the nickel-catalyzed Kumada-Tamao-Corriu coupling reaction. Among the imidazole and imidazoline derivatives in our investigations, the 2-phenyllimidazoline-nickel (II) chloride complex exhibited the highest catalytic activity.
Iwamoto, Ryo,Hayashi, Masahiko
p. 713 - 718
(2012)
Read Online

Nickel(II)-aryl complexes as catalysts for the Suzuki cross-coupling reaction of chloroarenes and arylboronic acids
A series of air- and moisture-stable Ni(II)-(σ-aryl) complexes, Ni(PPh3)2(aryl)X (X = Cl, Br), were employed as catalyst precursors in the Ni-catalyzed Suzuki cross-coupling reaction. These pre-catalysts easily form the catalytically active Ni(0) species in situ without the need of additional reducing agents. A general catalytic system involving Ni(PPh3)2(1-naph)Cl and PPh3 proved to be highly effective for the Suzuki reaction of aryl chlorides under mild conditions (at 60 °C in THF in the presence of K2CO3 as the base).
Chen, Chen,Yang, Lian-Ming
p. 2427 - 2430
(2007)
Read Online

Palladium- and copper-catalyzed homocoupling of organolead compounds: Synthesis of biaryls and diynes
The palladium- and copper-catalyzed dimerization of aryl- and alkynyllead triacetates to form biaryls and dialkynes under mild conditions is described.
Kang, Suk-Ku,Shivkumar, Uma,Ahn, Chuljin,Choi, Sang-Chul,Kim, Jae-Sun
p. 1893 - 1897
(1997)
Read Online

Oxidative coupling of alkylated anisole derivatives using MoCl5
Despite the Lewis acidic character of MoCl5 it can be employed for the selective oxidative coupling reaction of alkylated anisole derivatives without transalkylation or de-tert-butylation of the substrates. The spatial demand close to the donor
Mirk, Daniela,Wibbeling, Birgit,Fr?hlich, Roland,Waldvogel, Siegfried R.
p. 1970 - 1974
(2004)
Read Online

Copper- and manganese-catalyzed homocoupling of organostannanes in the presence of iodine
The copper- and manganese-catalyzed homocoupling of aryl-, alkenyl-, and alkynylstannanes to afford biaryls, 1,3-dienes, and 1,3-diynes were achieved in the presence of iodine at 100 °C in good yields.
Kang, Suk-Ku,Baik, Tae-Gon,Jiao, Xiang Hua,Lee, Yong-Tack
p. 2383 - 2384
(1999)
Read Online

Mechanism of C-C coupling reactions of aromatic halides, promoted by Ni(COD)2 in the presence of 2,2'-bipyridine and PPh3, to give biaryls
Reactions of aryl halides, such as phenyl bromide, p-methylphenyl bromide, p-acetylphenyl bromide, p-methoxyphenyl bromide, phenyl chloride, and phenyl iodide, with Ni(COD)2 (COD = 1,5-cyclooctadiene) in the presence of 2,2'-bipyridine (BPY) or PPh3 as the auxiliary ligand give the corresponding biaryl as the coupling product at 50-70 deg C in DMF.Reaction of phenyl bromide with Ni(COD)2-BPY in benzene at room temperature gives NiBr(Ph)(BPY) (1).Heating a DMF solution of a mixture of 1 and phenyl bromide at 60 deg C gives biphenyl, while 1 dissolved in DMF liberates biphenyl at room temperature.Reaction of a large excess amount of phenyl bromide with the Ni(COD)2 * BPY system obeys second-order kinetics to the nickel complex.Concentration of phenyl bromide in the range 0.2-7.2 mol dm-3 influences the reaction rate to little extent.Temperature dependence of the rate constants gives the kinetic parameters of ΔG333 = 90 kJ mol-1, ΔH333 = 60 kJ mol-1 and ΔS333 = -90 J mol-1 K-1, respectively.The reactivity of phenyl halide increases in the order, PhCl less than PhBr less than PhI.Substitution of the para hydrogen of phenyl bromide with an electron-withdrawing group causes lowering of the rate constant, whereas introduction of an electron-donating group like OCH3 enhances the reaction.The Hammett plot of the reaction shows linar correlation between the ? value of the substituent and the logarithm of the second-order rate constants giving the ρ value of -2.4.Based on the results, the mechanism of the coupling reaction of PhBr is proposed to involve disproportionation of the intermediate NiBr(Ph)(BPY) as the rate determining step to give NiPh2(BPY) which is responsible for the reductive elimination of biphenyl under the reaction conditions.
Yamamoto, Takakazu,Wakabayashi, Shoichiro,Osakada, Kohtaro
p. 223 - 237
(1992)
Read Online

SYNTHESIS AND MASS SPECTROMETRY OF SOME METHOXYLATED PCB
The syntheses of 46 methoxy-polychlorobiphenyls (MeO-CBs), containing 3 to 7 chlorine atoms, are described. The MeO-CBs were synthesized via the Cadogan diaryl coupling reaction of the appropriate polychloroaniline and polychloroanisole, or via the Ullmann coupling of a polychloroiodobenzene and 4-iodoanisole with subsequent chlorination of the isolated 4-MeO-CB product. The synthesized MeO-CBs were characterized by electron ionization (EI) mass spectrometry (MS) on an ion trap MS instrument and by EI and negative ion chemical ionization (NICI) on a quadrupole mass spectrometer. Both instruments gave similar EI spectra but the fragments were in general more abundant relative to the molecular ion, in the spectra obtained from the ion trap instrument. Characteristic fragmentation patterns were obtained by EI for ortho-, meta- and para-MeO-CBs, respectively, depending on the position of the MeO-group, with the exception of three meta-substituted MeO-heptaCBs, with a 3-MeO-2,4,6-trichloro-substitution pattern, that gave an abundant +-fragment, similar to para-substituted MeO-CBs. MS(NICI) of ortho-, meta- and para-MeO-CBs did not give any characteristic fragmentation patterns depending on the position of the MeO-group, except for ortho-substituted MeO-CBs that showed abundant fragments at -. The MS(NICI) gave approximately 10-50 times higher response for MeO-tetraCBs - MeO-heptaCBs than the MS(EI). The ion trap instrument (ITS40) has a somewhat lower detection-limit than the quadrupole MS when operated in the EI-mode.
Bergman, A.,Klasson Wehler, E.,Kuroki, H.,Nilsson, A.
p. 1921 - 1938
(1995)
Read Online

Ligand-free palladium catalysis of aryl coupling reactions facilitated by grinding
Ligand-free palladium-catalysed Suzuki coupling reactions and homo-couplings of boronic acids have been facilitated by grinding. The reactions are rapid (10-30 min) and can be performed without the need to exclude air and moisture.
Klingensmith, Liane M.,Leadbeater, Nicholas E.
p. 765 - 768
(2003)
Read Online

Ullmann homocoupling catalysed by gold nanoparticles in water and ionic liquid
The gold-catalysed Ullmann-type homocoupling of aryl halides is carried out with two different methodologies: (i) under micellar catalysis conditions in water and (ii) using a molten tetralkylammonium ionic liquid as the reaction medium. Glucose is used as a clean and renewable reductant. Morphology, size, and chemical composition of the gold nanoparticles were ascertained by X-ray photoelectron spectroscopy, transmission electron microscopy and dynamic light scattering analyses. A plausible reaction mechanism is proposed.
Monopoli, Antonio,Cotugno, Pietro,Palazzo, Gerardo,Ditaranto, Nicoletta,Mariano, Bruno,Cioffi, Nicola,Ciminale, Francesco,Naccia, Angelo
p. 2777 - 2788
(2012)
Read Online

An efficient protocol for palladium-catalyzed ligand-free Suzuki-Miyaura coupling in water
An in situ generated catalytic system based on PdCl2 and sodium sulfate exhibited excellent catalytic activity in the Suzuki-Miyaura cross-coupling reactions of aryl halides with arylboronic acids at room temperature in water. A similar catalytic system can be obtained with PdCl 2 and sodium chloride or sodium acetate and is equally effective in Suzuki-Miyaura cross-coupling reactions. This method offers a mild and efficient alternative to the existing protocols since the reaction is proceeded in water at room temperature under ligand free conditions. The Royal Society of Chemistry 2012.
Mondal, Manoj,Bora, Utpal
p. 1873 - 1876
(2012)
Read Online

Captured and cross-linked palladium nanoparticles
Polystyrene-poly(ethylene glycol) resin-captured cross-linked palladium nanopaticles were prepared via a straightforward route, and their heterogeneous behavior was truly confirmed by various tests. They were applied to aqueous Suzuki cross-coupling react
Cho, Jin Ku,Najman, Romain,Dean, Tony W.,Ichihara, Osamu,Muller, Christophe,Bradley, Mark
p. 6276 - 6277
(2006)
Read Online

Electroreductive coupling of organic halides in alcoholic solvents. An example: The electrosynthesis of biaryls catalysed by nickel-2,2' bipyridine complexes
Alcohols like methanol or ethanol are suitable solvents for achieving the electrosynthesis of biaryls from aryl halides according to a procedure which involves a catalysis by nickel-2,2'-bipyridine complexes. All electrolyses were carried out at constant current in an undivided cell fitted with an iron or duralumin sacrificial anode.
Courtois, Valerie,Barhdadi, Rachid,Troupel, Michel,Perichon, Jacques
p. 11569 - 11576
(1997)
Read Online

FeCl3 catalyzed barbier homocoupling reaction for synthesis of symmetric biaryls
Aseries of biaryls and biheteroaryls were synthesized by the Barbier reaction of aryl bromide withmagnesium powder and 1,2-dibromoethane in the presence of FeCl3 in THF under reflux reaction condition. The catalytic system differentiates itself fromother homocoupling reactions catalyzed by iron salts in that it requires neither the preliminary preparation of Grignard reagent nor the addition of an oxidant.
Lee, Adam Shih-Yuan,Chen, Pin-Lung,Chang, Yu-Ting,Tsai, Heng-Tser
p. 452 - 454
(2012)
Read Online

Acacia concinna pods: a natural and new bioreductant for palladium nanoparticles and its application to Suzuki–Miyaura coupling
Abstract: In this study, efficient, simple and greener approach is applied for the synthesis of palladium nanoparticles using aqueous extract of Acacia concinna, i.e., soap pods. The extract is mainly composed of saponin terpenoid which contains hydroxyl groups in its structure. This performs a versatile role as surfactant, reducing and stabilizing agent for palladium nanoparticles. The average particle size is found about 20?nm by using 30% extract (v/v) of A. concinna (soap-pod tree). Diverse techniques are used to characterize synthesized nanoparticles such as UV–visible, TEM and XPS analysis. The synthesized nanoparticles showed excellent activity in Suzuki–Miyaura coupling. The synthesized Pd NPs can be effectively reused for at least five times with excellent yield of product. Results confirmed this protocol as eco-benign, environmental-friendly, nontoxic and alternative to conventional other chemical methods. Graphical abstract: [Figure not available: see fulltext.].
Gaikwad,Undale,Kalel,Patil
p. 2135 - 2141
(2019)
Read Online

Rhodium/N-heterocyclic carbene-catalyzed cross-couplings of aryl arenesulfonates with arylboronic acids
The combination of rhodium(I) and N-hetercyclic carbenes (NHC) was found to be effective as a catalyst for cross-coupling reactions of aryl arenesulfonates with arylboronic acids, which gave rise to the desired biaryl compounds in good yields.
Zhang, Liang,Wu, Jie
p. 2409 - 2413
(2008)
Read Online

A nanostructured skeleton catalyst: Suzuki-coupling with a reusable and sustainable nanoporous metallic glass Pd-catalyst
Nanoporous metallic glass Pd, which was fabricated by dealloying of a glassy metallic alloy Pd30Ni50P20, exhibited a remarkable catalytic activity for the Suzuki-coupling reaction between iodoarenes and arylboronic acids under mild conditions. Moreover, the catalyst can be reused several times without a significant loss of catalytic activity.
Tanaka, Shinya,Kaneko, Tetsuro,Asao, Naoki,Yamamoto, Yoshinori,Chen, Mingwei,Zhang, Wei,Inoue, Akihisa
p. 5985 - 5987
(2011)
Read Online

Sonogashira cross-coupling on the Au(1 1 1) and Au(1 0 0) facets of gold nanorod catalysts: Experimental and computational investigation
The catalytic activity of well-defined gold nanorods enclosed by Au(1 1 1) and Au(1 0 0) surfaces is investigated for the Sonogashira cross-coupling reaction between phenylacetylene and 4-iodoanisole, which gives rise to two homo-coupling products (diphen
Lin, Jizhi,Abroshan, Hadi,Liu, Chao,Zhu, Manzhou,Li, Gao,Haruta, Masatake
p. 354 - 361
(2015)
Read Online

Perfluoro-tagged nano-palladium catalyst immobilized on fluorous silica gel: Application in the Suzuki-Miyaura reaction
The Suzuki-Miyaura reaction has been performed using a phosphine-free perfluoro-tagged palladium catalyst that is readily immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd-1/FSG). The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields, and very low palladium content ( 0.8 ppm) in the products was detected by ICP-AES. The catalyst can be recovered by simple filtration and reused several times without significant loss of activity.
Wan, Li,Cai, Chun
p. 105 - 108
(2012)
Read Online

An efficient catalyst for Suzuki-Miyaura coupling reaction in aqueous medium under aerobic conditions
A cylcopalladated complex, [Pd(Cl)(k2N,C-CH2C 6H2(Me)2CHNC6H3(Pr i)2]2 was found to be an excellent catalyst for Suzuki-Miyaura coupling of aryl halides with arylboronic acid in aqueous medium under aerobic conditions.
Chen, Chuan-Lin,Liu, Yi-Hung,Peng, Shie-Ming,Liu, Shiuh-Tzung
p. 521 - 523
(2005)
Read Online

Oxidative dimerization: Pd(II) catalysis in the presence of oxygen using aqueous media
Reported herein is a method for the formation of symmetric biaryls and dienes via oxidative dimerization of aryl and alkenyl boronic acids. These conditions utilized Pd(II) catalysts under an oxygen atmosphere with water as the solvent. The use of phase transfer catalysts promoted efficient and mild syntheses of a wide range of materials.
Parrish, Jay P.,Jung, Young C.,Floyd, Ryan J.,Jung, Kyung Woon
p. 7899 - 7902
(2002)
Read Online

Half-sandwich NHC-nickel(ii) complexes as pre-catalysts for the fast Suzuki coupling of aryl halides: A comparative study
Cationic half-sandwich nickel complexes of general formula [Ni(NHC)(NCMe)(η5-C5R5)](PF6) [NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) a, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) b; R = H, Me] were prepared from the reaction of their neutral homologues [Ni(NHC) Cl(η5-C5R5)] with 1 equiv. of KPF 6 in acetonitrile at room temperature. The new cationic complexes [Ni(IPr)(NCMe)(η5-C5Me5)](PF6) 3a, [Ni(IMes)(NCMe)(η5-C5Me5)](PF 6) 3b and [Ni(IMes)(NCMe)(η5-C5H 5)](PF6) 4b were obtained in high yield and were fully characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, elemental analyses, and in the case of 3a by a single-crystal X-ray diffraction study. The neutral analogue of 3a, [Ni(IPr) Cl(η5-C5Me5)] 1a was also structurally characterized. Their geometries were compared and no significant structural differences were observed. Nevertheless solution NMR spectroscopy established that the acetonitrile ligand of the cationic species is labile in solution. This results in the absence of any rotational significant barrier about the nickel-carbene carbon bond at ambient temperature in solution in the sterically congested cationic complexes 3a and 3b, in contrast to their neutral analogues 1a and [Ni(IMes)Cl(η5-C5Me5)] 1b. The neutral and the cationic complexes catalyzed the cross-coupling of phenylboronic acid with aryl halides in the absence of co-catalysts or reductants. Surprisingly, the neutral or cationic nature of the complexes proved to have almost no influence on the reaction yields and rates. However, complexes bearing the bulky electron-rich pentamethylcyclopentadienyl ligand were much more active than those bearing the cyclopentadienyl ligand, and TOF of up to 190 h-1, a high rate for nickel(ii) complexes under similar conditions, were observed with these species.
Ritleng, Vincent,Oertel, Anna Magdalena,Chetcuti, Michael J.
p. 8153 - 8160
(2010)
Read Online

Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites
The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had
Ali, Wajid,Anjana, S. S.,Bhattacharya, Trisha,Chandrashekar, Hediyala B.,Goswami, Nupur,Guin, Srimanta,Maiti, Debabrata,Panda, Sanjib,Prakash, Gaurav,Saha, Argha,Sasmal, Sheuli,Sinha, Soumya Kumar
supporting information
p. 1929 - 1940
(2022/02/01)

Highly dispersed palladium nanoparticles supported on graphitic carbon nitride for selective hydrogenation of nitro compounds and Ullmann coupling reaction
High catalytic activity and superior stability are important criterion for the utilization of a noble metal-based nano-composite catalyst. Herein, we report a facile synthesis of highly dispersed palladium nanoparticles embedded on graphitic carbon nitride (Pd@CNx) by ultrasound assisted method without aid of any external reducing agent. The Pd@CNx composite was well characterized by different techniques. This Pd@CNx shows effective catalytic activity towards easy dehydrogenation of sodium borohydride (NaBH4) and ammonia borane in aqueous medium and also can easily hydrogenate 4-nitrophenol to 4-aminophenol with fast kinetics. The catalyst is highly selective towards nitro groups in presence of other reducible groups with good stability. Furthermore, the catalyst exhibits superior catalytic activity towards Ullmann coupling reaction of different aryl halides with broad range of substrates scope with easy recovery of the catalyst and notable recycling property.
Bhowmik, Tanmay,Sadhukhan, Mriganka,Kempasiddaiah, Manjunatha,Barman, Sudip
(2022/02/09)

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
(2022/02/02)

Preparation and characterization of Cu based on 2-(5-Aminopyrimidin-2-yl)pyrimidin-5-amine as novel recyclable metal–organic frameworks for Suzuki reaction
For first time, in this work, a new, heterogeneous and recyclable catalyst was designed using immobilizing Cu on 2-(5-Aminopyrimidin-2-yl)pyrimidin-5-amine ([CuAPPA·2H2O]n) named metal–organic frameworks (MOFs). This catalyst was used for the synthesis of biaryl derivatives by Suzuki reaction. Suzuki reaction performed with mixing of the aryl halides with arylboronic acids in the DMF solvent conditions. Also, the prepared catalyst was characterized with different analytical techniques such as FT-IR, XRD, SEM, EDX, BET and ICP-AES analysis. [CuAPPA·2H2O]n catalyst displayed good to excellent yields catalytic efficiency for Suzuki reaction in comparison with to other catalysts. Also, the recoverability and reusability related to this catalyst was checked by a simple filtration with reserving its activity even after several cycles.
Mohammadnia, Majid
(2021/11/24)

Suzuki–Miyaura cross-coupling reaction assisted by palladium nanoparticles-decorated zeolite 13X nanocomposite: a greener approach
Heterogeneous catalysts govern the field of catalysis due to their easy separation from a reaction mixture, reusability, and prevention of agglomeration, making them more efficient catalysts than homogeneous catalysts. Herein, we report the eco-friendly synthesis of a novel heterogeneous catalyst, viz. palladium nanoparticles (Pd NPs) decorated over zeolite 13X nanocomposite using dried fruits of Terminalia chebula Retz. as the reducing and stabilizing agent and its performance as a promising catalyst for the Suzuki–Miyaura coupling reactions. The particle size, crystallinity, morphology, and textural properties of the catalyst were identified using Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis which confirmed the presence of palladium nanoparticles on the surface of zeolite 13X. The FESEM images revealed the presence of spherical-shaped Pd NPs over the cubical particles of zeolite 13X. The average particle size of the palladium nanoparticles was found to be in the range of 6–7?nm and was polycrystalline in nature. From BET analysis, it was inferred that the decoration of Pd NPs decreased the surface area of zeolite 13X (615.5 m2/g to 548.334 m2/g), thus leaving pores unoccupied. This study showed the efficiency of this novel catalyst in the formation of biaryl derivatives using low palladium loadings (0.0012?mol%) giving good to excellent yields (90–99%) within short reaction times (10–225?min) with high TONs (> 79,000) and TOFs (> 21,000). Both electron-donating and electron-withdrawing aryl halides and aryl boronic acids reacted smoothly in the presence of K2CO3 as a base and EtOH/H2O (1:1) as the solvent. Besides, the catalyst could be recycled and reused for 5 consecutive runs with minimal loss of its efficiency. The supremacy of this catalyst could well be exploited in future for various organic transformations. Graphical abstract: [Figure not available: see fulltext.].
Deepika, Raja,Sethuraman, Mathur Gopalakrishnan
p. 1111 - 1128
(2022/01/22)

Microcrystalline Cellulose-Supported Gold Nanoparticle Catalysts for Homocoupling of Phenylboronic Acids
A solid-grinding strategy for the large-scale synthesis of solid microcrystalline cellulose (MCC)-supported gold nanoparticle (NP) catalysts without using solvents and a sophisticated purification technique is reported. In contrast to typical solution-based methods, the deposition of high loading of gold NPs with greater uniformity on native MCC polymers without chemical modifications was achieved rapidly by manual grinding. The Fourier transform infrared (FT-IR) study revealed that the abundant hydroxyl functional groups present on the MCC support could effectively hold tiny gold NPs through hydrogen bonding between the ?OH groups of MCC and gold NPs, thereby making the MCC-supported gold NPs stable heterogeneous catalysts. Thus, the Au/MCC catalyst exhibits higher catalytic activity and selectivity toward homocoupling of phenylboronic acids into corresponding biphenyls in water under air. Compared to other solid-supported gold NP catalysts, the MCC-supported gold catalysts showed greater catalytic activity and selectivity in the homocoupling of phenylboronic acids. The kinetics study on the homocoupling reaction catalyzed by Au/MCC reveals that the catalysts possess much lower apparent activation energy than the reported gold catalysts. Thus, the present sustainable approach may inspire more studies on the design of renewable biopolymer matrix-supported gold NPs in a large scale for heterogeneous catalysis.
Murugadoss, Arumugam,Paul Reddy, Kalvakunta
p. 2205 - 2212
(2022/03/01)

Cu(ii)-vitamin C-complex catalyzed photo-induced homocoupling reaction of aryl boronic acid in base-free and visible light conditions
In this work, the photocatalytic efficiency of Cu(ii)-vitamin C complex immobilized on titanium dioxide nanoparticles was exploited in the photo-assisted homocoupling reaction of aryl boronic acids under heterogeneous conditions. The homocoupling reaction affords the corresponding symmetrical biaryls in 50-97% yields at ambient temperature in the air under visible light irradiation without any need for any additive such as base or oxidant. This method tolerates various substituents on the aryl boronic acids such as halogen, carbonyl, and a nitro group. The light-dependent photocatalytic performance of the title catalyst evaluated by action spectra revealed a maximum apparent quantum efficiency (AQYs) at 410 nm demonstrating the visible-light-driven photocatalytic reaction. The as-prepared nano biophotocatalyst proved to be reusable at least six times without losing its activity. Thus this work exhibits a favorable method from the environmental and economic point of view which enables the industrially important reactions such as coupling reactions, to be carried out efficiently under photocatalytic and practically attainable conditions.
Feizpour, Fahimeh,Jafarpour, Maasoumeh,Pourmorteza, Narges,Rezaeifard, Abdolreza
p. 4931 - 4938
(2022/02/19)

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)

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,Luo, Chengkai,Xu, Caifeng,Huang, Bin
p. 1339 - 1346
(2021/12/02)

Silk?Fibroin-Supported Palladium Catalyst for Suzuki-Miyaura and Ullmann Coupling Reactions of Aryl Chlorides
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
supporting information

(2022/02/03)

CuI in biorenewable basic medium: Three novel and low E-factor Suzuki-Miyaura cross-coupling reactions
In this article, we have disclosed three inexpensive and novel copper-catalyzed C(sp2)–C(sp2) coupling reactions of substituted aryl/heteroaryl halides with arylboronic acids by employing water extract of pomegranate ash (WEPA) as biorenewable base and aqueous reaction medium. CuI/WEPA, CuI/WEPA/DABCO, CuI/WEPA/SPhos catalytic systems were developed for the present Suzuki-Miyaura coupling. WEPA has been found to be the effective base and reaction medium for copper-catalysed Suzuki-Miyaura reactions with and without ligands to provide good to high yields of coupling products. This method has remarkable advantages like inexpensive and waste-derived biorenewable base, low catalyst loading, moderate temperature, replacement of precious palladium with abundant copper, no or negligible contamination of copper in products, low E-factor, high chemoselectivity and a large substrate scope.
Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Venkateswarlu, Katta
(2022/03/31)

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.
(2021/11/11)

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
(2021/12/01)

Acetonitrile and benzonitrile as versatile amino sources in copper-catalyzed mild electrochemical C-H amidation reactions
A mild, efficient electrochemical approach to the site-selective direct C-H amidation of benzene and its derivatives with acetonitrile and benzonitrile has been developed. It has been shown that joint electrochemical oxidation of various arenes in the presence of a copper salt as a catalyst and nitriles leads to the formation of N-phenylacetamide from benzene and N-benzylacetamides from benzyl derivatives (up to 78% yield). A favorable feature of the process is mild conditions (room temperature, ambient pressure, no strong oxidants) that meet the criteria of green chemistry.
Budnikova, Yulia,Kononov, Alexander,Rizvanov, Ildar,Strekalova, Sofia
p. 37540 - 37543
(2021/12/07)

Ligand and Base Free Synthesis of Biaryls from Aryl Halides in Aqueous Media with Recyclable Ti0.97Pd0.03O1.97 Catalyst
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
p. 3313 - 3322
(2021/03/04)

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)

Pd-catalyzed cross-electrophile Coupling/C-H alkylation reaction enabled by a mediator generatedviaC(sp3)-H activation
Transition-metal-catalyzed cross-electrophile C(sp2)-(sp3) coupling and C-H alkylation reactions represent two efficient methods for the incorporation of an alkyl group into aromatic rings. Herein, we report a Pd-catalyzed cascade cross-electrophile coupling and C-H alkylation reaction of 2-iodo-alkoxylarenes with alkyl chlorides. Methoxy and benzyloxy groups, which are ubiquitous functional groups and common protecting groups, were utilized as crucial mediatorsviaprimary or secondary C(sp3)-H activation. The reaction provides an innovative and convenient access for the synthesis of alkylated phenol derivatives, which are widely found in bioactive compounds and organic functional materials.
Jiang, Hang,Wu, Zhuo,Zhang, Yanghui
p. 8531 - 8536
(2021/07/02)

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)

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
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
(2020/09/17)

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
(2021/04/23)

Synthesis of ultrafine AuPd bimetallic nanoparticles using a magnetite-cored poly(propyleneimine) dendrimer template and its sustainable catalysis of the Suzuki coupling reaction
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
p. 14227 - 14235
(2021/08/16)

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)
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
(2020/12/14)

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
(2021/01/11)

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)

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.
Prasad, Sana Siva,Naidu, Bandameeda Ramesh,Hanafiah, Marlia M.,Lakshmidevi, Jangam,Marella, Ravi Kumar,Lakkaboyana, Sivarama Krishna,Venkateswarlu, Katta
(2021/09/13)

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 Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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
(2021/07/31)

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
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
(2021/02/12)

New Nickel-Based Catalytic System with Pincer Pyrrole-Functionalized N-Heterocyclic Carbene as Ligand for Suzuki-Miyaura Cross-Coupling Reactions
A new catalytic system with Ni(NO3)2·6H2O as the catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as the ligand was employed in the Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids. With 5 mol% catalyst, the catalytic reactions proceeded at 160 °C, giving coupling products in isolated yields of up to 94% in short reaction times (1-4 h). The system worked efficiently with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups. Steric effects were observed for both aryl iodides and arylboronic acids. It is proposed that the reactions underwent a Ni(I)/Ni(III) catalytic cycle.
Guo, Zhifo,Lei, Xiangyang
supporting information

(2021/09/11)

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)

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)

N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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
p. 6367 - 6374
(2021/09/29)

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)

Aryl Diazonium Salts: Powerful Arylating Agents for Catellani-Typeortho-Arylation
The Catellani reaction provides an efficient synthetic approach to polyfunctionalized arenes. However, the selectiveortho-arylating reagents employed in these reactions have been strictly limited to activated bromoarenes. As demonstrated in this work, aryl diazonium salts bearing both electron-donating and electron-withdrawing substituents, after in situ transformations with KI into the corresponding iodoarenes, were efficient arylating reagents for Catellani typeortho-arylation approaches.
Fu, Ying,Guo, Liang-Liang,Zhang, Yu-Xia
supporting information
p. 17437 - 17444
(2021/12/02)

Cu-Catalyzed Oxidative Allylic C-H Arylation of Inexpensive Alkenes with (Hetero)Aryl Boronic Acids
Herein, we present a regioselective Cu-catalyzed oxidative allylic C(sp3)-H arylation by radical relay using a broad range of heteroaryl boronic acids with inexpensive and readily available unactivated terminal and internal olefins. This C(sp2)-C(sp3) allyl coupling has the advantage of using cheap, abundant, and nontoxic Cu2O without the need to use prefunctionalized alkenes, thus offering an alternative method to allylic arylation reactions that employ more traditional coupling partners with preinstalled leaving groups (LGs) at the allylic position.
Pal, Suman,Cotard, Marine,Gérardin, Baptiste,Hoarau, Christophe,Schneider, Cédric
supporting information
p. 3130 - 3135
(2021/05/05)

Identification of a Surprising Boronic Acid Homocoupling Process in Suzuki-Miyaura Cross-Coupling Reactions Utilizing a Hindered Fluorinated Arene
The Suzuki-Miyaura cross-coupling reaction of 2-bromo-1,3-bis(trifluoromethyl)benzene with arylboronic acids was evaluated and determined to suffer from the formation of large amounts of boronic acid homocoupling products in conjunction with dehalogenation. Homocoupling product formation in this process likely occurs through a rare protonolysis/second transmetalation event rather than by the well-established mechanism requiring the involvement of O 2. The scope of this boronic acid homocoupling reaction was investigated and shown to predominate with electron-deficient arylboronic acids. Finally, a good yield of cross-coupling products could be obtained by employing dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (SPhos) as the ligand.
Gargaro, Samantha L.,Dunson, Bre'Shon,Sieber, Joshua D.
supporting information
p. 511 - 516
(2020/09/21)

Eco-Friendly Methodology for the Formation of Aromatic Carbon–Heteroatom Bonds by Using Green Ionic Liquids
A new sustainable method is reported for the formation of aromatic carbon–heteroatom bonds under solvent-free and mild conditions (no co-oxidant, no strong acid and no toxic reagents) by using a new type of green ionic liquid. The bromination of methoxy arenes was chosen as a model reaction. The reaction methodology is based on only using natural sodium bromine, which is transformed into an electrophilic brominating reagent within an ionic liquid, easily prepared from the melted salt FeCl3 hexahydrate. Bromination reactions with this in-situ-generated reagent gave good yields and excellent regioselectivity under simple and environmentally friendly conditions. To understand the unusual bromine polarity reversal of sodium bromine without any strong oxidant, the molecular structure of the reaction medium was characterised by Raman and direct infusion electrospray ionisation mass spectroscopy (ESI-MS). An extensive computational investigation using density functional theory methods was performed to describe a mechanism that suggests indirect oxidation of Br? through new iron adducts. The versatility of the methodology was successively applied to nitration and thiocyanation of methoxy arenes using KNO3 and KSCN in melted hexahydrated FeCl3.
Richards, Kenza,Petit, Eddy,Legrand, Yves-Marie,Grison, Claude
supporting information
p. 809 - 814
(2020/11/30)

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)

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)

Late-Stage Carbon Isotope Exchange of Aryl Nitriles through Ni-Catalyzed C-CN Bond Activation
A facile one-pot strategy for 13CN and 14CN exchange with aryl, heteroaryl, and alkenyl nitriles using a Ni phosphine catalyst and BPh3 is described. This late-stage carbon isotope exchange (CIE) strategy employs labeled Zn(CN)2 to facilitate enrichment using the nonlabeled parent compound as the starting material, eliminating de novo synthesis for precursor development. A broad substrate scope encompassing multiple pharmaceuticals is disclosed, including the preparation of [14C] belzutifan to illustrate the exceptional functional group tolerance and utility of this labeling approach. Preliminary experimental and computational studies suggest the Lewis acid BPh3 is not critical for the oxidative addition step and instead plays a role in facilitating CN exchange on Ni. This CIE method dramatically reduces the synthetic steps and radioactive waste involved in preparation of 14C labeled tracers for clinical development.
Reilly, Sean W.,Lam, Yu-Hong,Ren, Sumei,Strotman, Neil A.
supporting information
p. 4817 - 4823
(2021/04/07)

Palladium imine-pyridine-imine complex immobilized on graphene oxide as a recyclable catalyst for the carbonylative homo-coupling of aryl halides
A heterogeneous 3-N,N,N-(II) Pd(OAc)2 catalyst was prepared from the reaction of Pd(OAc)2 with Si-Prn-N = C-Py-C = N-Prn-Si immobilized on graphene oxide (GO-Si-Prn-N = C-Py-C = N-Prn-Si-GO). The prepared catalyst was characterized by inductively coupled plasma optical emission spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, UV-vis spectroscopy, BET surface area, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The catalyst was employed as a heterogeneous catalyst for carbonylative homo-coupling of aryl iodides and bromides under carbon monoxide gas-free condition. Cr(CO)6 was used as the carbon monoxide source and the desired symmetrical diaryl ketones were achieved in good to excellent yields. Moreover, the catalyst was reused up to five consecutive cycles without significant loss of activity.
Niakan, Mahsa,Asadi, Zahra,Khosrozadeh, Fatemeh
p. 850 - 863
(2020/12/18)

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)

Stereospecific Iron-Catalyzed Carbon (sp2)-Carbon (sp2) Cross-Coupling of Aryllithium with Vinyl Halides
We present herein an efficient synthetic protocol involving iron-catalyzed cross-coupling of organolithium compounds with vinyl halides as key coupling partners. More than 30 examples were obtained with moderate to good yields and high stereoselectivities. The practicality of this method is evidenced by a gram-scale synthesis. In addition, a preliminary mechanistic investigation was also performed.
Chen, Peng,Peng, Xiao-Shui,Wang, Zhi-Yong,Wong, Henry N. C.
supporting information
p. 4385 - 4390
(2021/06/27)

Bathocuproine-Enabled Nickel-Catalyzed Selective Ullmann Cross-Coupling of Two sp 2-Hybridized Organohalides
Cross-coupling reactions are essential for the synthesis of complex organic molecules. Here, we report a nickel-catalyzed Ullmann cross-coupling of two sp 2-hybridized organohalides, featuring high cross-selectivity when the two coupling partners are used in a 1:1 ratio. The high chemoselectivity is governed by the bathocuproine ligand. Moreover, the mild reductive reaction conditions allow that a wide range of functional groups are compatible in this Ullmann cross-coupling.
Li, Yuqiang,Yin, Guoyin
supporting information
p. 1657 - 1661
(2021/09/13)

Cobalt-catalyzed cross-coupling reactions of aryl- And alkylaluminum derivatives with (hetero)aryl and alkyl bromides
A simple cobalt complex, such as Co(phen)Cl2, turned out to be a highly efficient and cheap precatalyst for a host of cross-coupling reactions involving aromatic and aliphatic organoaluminum reagents with aryl, heteroaryl and alkyl bromides. New C(sp2)-C(sp2) and C(sp2)-C(sp3) bonds were formed in good to excellent yields and with high chemoselectivity, under mild reaction conditions.
Dilauro, Giuseppe,Messa, Francesco,Bona, Fabio,Perrone, Serena,Salomone, Antonio
supporting information
p. 10564 - 10567
(2021/10/19)

Kinetically Controlled Reticular Assembly of a Chemically Stable Mesoporous Ni(II)-Pyrazolate Metal-Organic Framework
The application scope of metal-organic frameworks (MOFs) is severely restricted by their weak chemical stability and limited pore size. A robust MOF with large mesopores is highly desired, yet poses a great synthetic challenge. Herein, two chemically stable Ni(II)-pyrazolate MOFs, BUT-32 and -33, were constructed from a conformation-matched elongated pyrazolate ligand through the isoreticular expansion. The two MOFs share the same sodalite-type net, but have different pore sizes due to the network interpenetration in BUT-32. Controlled syntheses of the two MOFs have been achieved through precisely tuning reaction conditions, where the microporous BUT-32 was demonstrated to be a thermodynamically stable product while the mesoporous BUT-33 is kinetically favored. To date, BUT-32 represents the first example of Ni4-pyrazolate MOF whose structure was unambiguously determined by single-crystal X-ray diffraction. Interestingly, the kinetic product BUT-33 integrates 2.6 nm large mesopores with accessible Ni(II) active sites and remarkable chemical stability even in 4 M NaOH aqueous solution and 1 M Grignard reagent. This MOF thus demonstrated an excellent catalytic performance in carbon-carbon coupling reactions, superior to other Ni(II)-MOFs including BUT-32. These findings highlight the importance of kinetic control in the reticular synthesis of mesoporous MOFs, as well as their superiority in heterogeneous catalysis.
He, Tao,Huang, Zhehao,Yuan, Shuai,Lv, Xiu-Liang,Kong, Xiang-Jing,Zou, Xiaodong,Zhou, Hong-Cai,Li, Jian-Rong
supporting information
p. 13491 - 13499
(2020/09/02)

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)

Discovery and mechanistic investigation of Pt-catalyzed oxidative homocoupling of benzene with PhI(OAc)2
We present a Pt-catalyzed direct coupling of benzene to biphenyl. This catalytic reaction employs a cyclometalated platinum(ii) complex [PtMe(bhq)(SMe2)] (bhq = benzo[h]quinolate) with PhI(OAc)2 as an oxidant and does not require an acid, a co-catalyst or a solvent. The reaction kinetics and characterization of potential catalytic species are reported. The reaction is first-order in Pt and second-order in benzene, which implicates the second C-H activation step as rate-determining. A Pt(ii)/Pt(iv) catalytic cycle is suggested. The reaction commences by oxidation of the Pt(ii) complex to give the platinum(iv) species [Pt(bhq)(SMe2)(OAc)2](OAc) followed by C-H activation of benzene to afford the intermediate [PtPh(bhq)(SMe2)(OAc)](OAc) concurrently with the release of HOAc. A second benzene molecule reacts similarly to give the diphenyl intermediate [PtPh2(bhq)(SMe2)](OAc). C-C bond forming reductive elimination ensues to regenerate Pt(ii) and complete the catalytic cycle. The proposed mechanism has been examined by DFT computations, which provide support to experimental findings.
Abu-Omar, Mahdi M.,Nabavizadeh, S. Masoud,Niroomand Hosseini, Fatemeh,Park, Chan,Wu, Guang
supporting information
p. 2477 - 2486
(2020/03/05)

An insight into the novel covalent functionalization of multi-wall carbon nanotubes with pseudopeptide backbones for palladium nanoparticles immobilization: A versatile catalyst towards diverse cross-coupling reactions in bio-based solvents
Materials functionalization with multicomponent reactions (MCRs) has grabbed a lot of attention nowadays due to the integration of outstanding features of MCRs with materials domains. Herein, we put the spotlight on the isocyanides and Meldrum's acid-based MCRs route for the one-pot covalent functionalization of multi-wall carbon nanotubes (MWCNTs) which led to pseudopeptide-decorated MWCNTs with the ability to immobilized palladium nanoparticles and serve as a neoteric catalytic system. Characterization of the synthesized nanocatalyst was carried out by FT-IR, 1H NMR, XRD, SEM, TEM, EDX and TGA. The catalytic activities of the nanocatalyst for diverse carbon-carbon cross-coupling reactions were examined in bio-based solvents. The results showed the catalytic performance of the nanocatalyst for the formation of Csp2-Csp2, Csp-Csp2 and Csp-Csp bonds through homocoupling and intermolecular Ullmann, C[sbnd]H arylation, Mizoroki-Heck, Sonogashira and Glaser coupling reactions with considerable improvements in the yield, reaction times, bio-based media and chemoselectivity of the procedures. Additionally, this method demonstrated a high potential for recycling of heterogeneous catalysts by maintaining their initial performances without any evidence of the Pd leaching.
Afshari, Ronak,Emad Hooshmand, Seyyed,Atharnezhad, Mojtaba,Shaabani, Ahmad
(2019/11/26)

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
(2020/02/25)