- Homocoupling of Organostannanes Catalyzed by Iminophosphine-Palladium
-
An iminophosphine-palladium complex has been successfully utilized as a catalyst for the oxidative homocoupling reaction of organostannanes using air as an oxidant.
- Shirakawa, Eiji,Murota, Yasubumi,Nakao, Yoshiaki,Hiyama, Tamejiro
-
-
Read Online
- Immobilization of copper(II) in organic-inorganic hybrid materials: A highly efficient and reusable catalyst for the classic Ullmann reaction
-
The immobilization of copper(II) in organic - inorganic (silica gel) hybrid materials as catalysis for the homocoupling of aryl halides (classic Ullmann reaction) has been described. The homocoupling of aryl iodides, bromides and chlorides underwent smoothly in the presence of a 3-(2-aminoethylamino)propyl- functionalized silica gel immobilized copper(II) catalyst. The protocol involved the use of DMSO as the solvent and potassium fluoride as the base. The reactions generated the corresponding homocoupling products in good to excellent yields. Furthermore, the silica-supported copper(II) could be recovered and recycled by simple filtration and used for five consecutive trials without loss of its reactivity. Thieme Stuttgart.
- Wu, Qiang,Wang, Lei
-
-
Read Online
- Carbon-carbon bond formation via homocoupling reaction of substrates with a broad diversity in water using Pd(OAc)2 and agarose hydrogel as a bioorganic ligand, support and reductant
-
In this study, we have presented a new catalytic system in which Pd(OAc)2 has been used as a pre-catalyst and agarose as a degradable bioorganic ligand, support and reductant for carbon-carbon bond formation via homocoupling reaction of different aryl halides, β-bromo styrene, phenylboronic acid and phenylacetylene as the substrates. The reactions proceeded smoothly with high yields at temperature 100 °C in water without using any organic co-solvent, phosphorus ligand or reducing agents. The catalyst is recyclable and has been recycled for four times with a tiny amount of leaching of Pd into the reaction media. The amount of leaching has been determined by ICP analysis.
- Firouzabadi, Habib,Iranpoor, Nasser,Kazemi, Faezeh
-
-
Read Online
- Water-dispersible and magnetically separable gold nanoparticles supported on a magnetite/s-graphene nanocomposite and their catalytic application in the Ullmann coupling of aryl iodides in aqueous media
-
Water-dispersible sulfonated graphene (s-G) was synthesized by anchoring sulfonic acid groups on graphene sheets. Subsequently, magnetically separable Fe3O4/s-G was synthesized from the Fe3O 4 nanoparticles decorated on s-G sheets by the co-precipitation method of iron ions. Finally, Fe3O4/s-G was successfully decorated with gold nanoparticles in a facile route by reducing chloroauric acid in the presence of sodium dodecyl sulfate, which is used as both a surfactant and reducing agent. The obtained Au/Fe3O4/s-G nanocomposite remained soluble in water, but could be easily separated from reaction solutions by an external magnetic field and then used as a heterogeneous catalyst for the Ullmann coupling reaction in water. The catalytic activity reduction was not significant even after five consecutive reaction runs due to the efficient magnetic separation, the high dispersion and stability of the catalyst in aqueous solution.
- Dabiri, Minoo,Shariatipour, Monire,Kazemi Movahed, Siyavash,Bashiribod, Sahareh
-
-
Read Online
- DAB-Cy as an inexpensive and effective ligand for palladium-catalyzed homocoupling reaction of aryl halides
-
A novel catalytic system of PdCl2(CH3CN)2 with N,N′-dicyclohexyl-1,4-diazabutadiene (DAB-Cy) ligand was successfully used in reductive coupling of aryl halides.
- Ma, Ning,Duan, Zheng,Wu, Yangjie
-
-
Read Online
- Au-Pd bimetallic nanoparticles supported on a high nitrogen-rich ordered mesoporous carbon as an efficient catalyst for room temperature Ullmann coupling of aryl chlorides in aqueous media
-
An ionic liquid derived highly nitrogen-rich mesoporous carbon supported Au-Pd alloy was found to be an efficient and recyclable catalyst for the Ullmann coupling reaction of various aryl chlorides at room temperature in aqueous media.
- Karimi, Babak,Barzegar, Hossein,Vali, Hojatollah
-
-
Read Online
- Band Gap Modification of TiO2 Nanoparticles by Ascorbic Acid-Stabilized Pd Nanoparticles for Photocatalytic Suzuki–Miyaura and Ullmann Coupling Reactions
-
In this study, synthesis, characterization and photocatalytic performance of surface-modified TiO2 nanoparticles with ascorbic acid-stabilized Pd nanoparticles are presented. The structure, composition and morphology of as-prepared nanophotocatalyst were characterized by UV-DRS, FT-IR, ICP-AES, TEM and XPS analysis. Ascorbic acid-stabilized Pd nanoparticles induced visible light driven photocatalytic property on the surface of TiO2 which are otherwise insensitive to visible light owing to the wide band gap. The catalytic system worked well for the Suzuki–Miyaura cross-coupling and Ullmann homocoupling under compact fluorescent light as a visible source with significant activity, selectivity and recyclability. Good to excellent yields of biaryl products were obtained for various aryl halides having different electronic demands and even aryl chlorides. Our results proposed that the improved photoactivity predominantly benefits from the synergistic effects of ascorbic acid-stabilized Pd nanoparticles on TiO2 nanoparticles that cause efficient separation and photoexcited charge carriers and photoredox capability of nanocatalyst. Thus, tuning of band gap of TiO2 making a visible light sensitive photocatalyst, demonstrates a significant advancement in the photocatalytic Suzuki–Miyaura and Ullmann coupling reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Feizpour, Fahimeh,Jafarpour, Maasoumeh,Rezaeifard, Abdolreza
-
-
Read Online
- An effective and environment-friendly system for Cu NPs@RGO-catalyzed C-C homocoupling of aryl halides or arylboronic acids in ionic liquids under microwave irradiation
-
As an outstanding mesh catalyst support, reduced graphene oxide (RGO) has attracted enormous attention in recent years. Cu nanoparticles-RGO (Cu NPs@RGO) as a green catalyst was prepared through a green reduction method by ascorbic acid in N-methyl-2-pyrrolidone. The structure of prepared Cu NPs@RGO was characterized. The catalytic activity of Cu NPs@RGO was estimated. A green and efficient method for synthesizing symmetrical biaryl compounds was developed by Cu NPs@RGO-catalyzed Ullmann homocoupling of aryl halides or arylboronic acids in ionic liquids under microwave (MW) irradiation. The catalytic system could be recycled five times with slight loss of activity. Through this method, nine kinds of biaryls were prepared by homocoupling reaction of the corresponding aryl iodides, aryl bromides, aryl chlorides and aryl boronic acids in moderate to good yields.
- Zhao, Hongyan,Mao, Guijie,Han, Huatao,Song, Jinyi,Liu, Yang,Chu, Wenyi,Sun, Zhizhong
-
-
Read Online
- Direct homocoupling of aryl halides catalyzed by palladium
-
Symmetrical functionnalized biaryls are obtained in good yield via homocoupling of aryl halides, bromo or iodo ones, using the combination of Pd(OAc)2 and nBu4NBr as catalyst system.
- Penalva, Vincent,Hassan, Jwanro,Lavenot, Laurence,Gozzi, Christel,Lemaire, Marc
-
-
Read Online
- PdAu alloy nanoparticles supported on nitrogen-doped carbon black as highly active catalysts for Ullmann coupling and nitrophenol hydrogenation reactions
-
Noble metal-based catalysts have been proven to be active for catalytic organic reactions. The selectivity and conversion can be improved by integration with proper carrier materials, and further modulated by tuning the composition as well as the electronic structure of the active noble metals. Compared with unsupported monometallic catalysts, the synergistic interactions between neighboring metals and the combined effects between the carrier materials and the active components often give rise to positive influences on the enhancement of the catalytic efficiency and selectivity. In this work, we report a facile process for the fabrication of nitrogen-doped carbon black (NCB) supported PdAu bimetallic nanoparticles (NPs) with a uniform dispersion and narrow size distribution. The PdAu/NCB catalyst with a Pd/Au mole ratio of 1/1 shows the highest activity towards both Ullmann coupling reactions of aryl halides and the hydrogenation reaction of nitrophenols. Moreover, this bimetallic catalyst also exhibits a superior recycling durability to that of monometallic Pd/NCB and Au/NCB catalysts. The enhanced catalytic performance of the bimetallic catalyst is mainly due to the large BET specific surface area (125.45 m2 g-1) and the synergy between the individual components of the catalyst.
- Han, Fengyan,Xia, Jiawei,Zhang, Xinglong,Fu, Yongsheng
-
-
Read Online
- Synthesis of gold nanoparticles decorated on sulfonated three-dimensional graphene nanocomposite and application as a highly efficient and recyclable heterogeneous catalyst for Ullmann homocoupling of aryl iodides and reduction of p-nitrophenol
-
Gold nanoparticles were decorated onto sulfonated three-dimensional graphene (3DG-SO3H) through spontaneous chemical reduction of HAuCl4 by 3DG-SO3H. This nanocomposite exhibited excellent catalytic activity for the synthesis of symmetric biaryls via the Ullmann homocoupling of aryl iodides in an aqueous medium. Additionally, this nanocomposite was used as a catalyst for the reduction of p-nitrophenol to p-aminophenol. The catalyst could be used more than six times successively without significant deactivation.
- Dabiri, Minoo,Kashi, Seyede Razie Banifatemi,Lehi, Noushin Farajinia,Bashiribod, Sahareh
-
-
Read Online
- Palladium-catalyzed arylation of α,α-difluoro-allylic-β-hydroxyester
-
The aryl-substituted α,α-difluoro-allylic-β-hydroxyesters and aryl-substituted α,α-difluoroketones were obtained via the coupling reaction of aryl iodides with α,α-difluoro-allylic-β-hydroxyester in the presence of Pd(OAc)2 as the catalyst and Et3N as the base.
- Fang, Xiang,Yang, Xueyan,Yang, Xianjin,Zhao, Min,Chen, Guorong,Wu, Fanhong
-
-
Read Online
- Au25 nanocluster-catalyzed Ullmann-type homocoupling reaction of aryl iodides
-
The Au25(SR)18/CeO2 nanocluster catalyst showed high activity in the homocoupling of aryl iodides (e.g. up to 99.8% yield with iodobenzene) and excellent recyclability. The Royal Society of Chemistry.
- Li, Gao,Liu, Chao,Lei, Yu,Jin, Rongchao
-
-
Read Online
- Thiazole-based non-symmetric NNC-palladium pincer complexes as catalytic precursors for the Suzuki-Miyaura C-C coupling
-
We report an efficient synthesis of new non-symmetric pincer palladacycles 2a-i, containing a [NNC]-tridentate ligand formed by a hydrazone and a thiazolyl moiety as sources of N-donor atoms. These catalytic precursors were tested in the Suzuki-Miyaura cross coupling reaction using a variety of aryl boronic acids with aryl bromides or chlorides using water as solvent. Complex 2a displays the best catalytic performance under aerobic conditions, affording the coupling products in good to high yields. In all cases, the cross-coupling reaction was conducted under IR irradiation, allowing a decrease in the reaction time.
- Camacho-Espinoza, Martín,Reyes-Deloso, Alberto,Toscano, R. Alfredo,Penieres-Carrillo, J. Guillermo,López-Cortés, José G.,Ortega-Alfaro, M. Carmen,Ortega-Jiménez, Fernando
-
-
Read Online
- DEDIAZONIATION OF ARENEDIAZONIUM SALT WITH TRIVALENT PHOSPHORUS COMPOUNDS BY ONE-ELECTRON TRANSFER MECHANISM
-
Trivalent phosphorus compounds, triphenylphosphine and triethyl phosphite, gave rise to dediazoniation of an arenediazonium salt in alcoholic solvent at ambient temperature in the dark.The reaction was well interpreted in terms of radical-chain mechanism initiated by an electron transfer from the trivalent phosphorus to a diazonium salt, which postulates a cation radical from the trivalent phosphorus as an intermediate.
- Yasui, Shinro,Fujii, Masayuki,Kawano, Chihiro,Nishimura, Yukihiro,Ohno, Atsuyoshi
-
-
Read Online
- Highly water-dispersible magnetite-supported Pd nanoparticles and single atoms as excellent catalysts for Suzuki and hydrogenation reactions
-
The molecule 4-(diphenylphosphino)benzoic acid (dpa) anchored on the surface of magnetite nanoparticles permits the easy capture of palladium ions that are deposited on the surface of the magnetite nanoparticles after reduction with NaBH4. Unexpectedly, a significant fraction of dpa is removed in this process. Samples of Fe3O4dpa@Pdx containing different Pd loadings (x = 0.1, 0.3, 0.5 and 1.0 wt%) were prepared, and their catalytic efficiency for the Suzuki C-C coupling reaction was studied. The best catalyst was Fe3O4dpa@Pd0.5, which gave the highest TOF published to date for the reaction of bromobenzene with phenylboronic acid in a mixture of ethanol/water (1/1). Interestingly, the same reaction carried out in water also produced excellent yields of the resulting C-C coupling product. The behaviour of other bromide aryl molecules was also investigated. The best catalytic results for the aqueous phase reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) were obtained using Fe3O4dpa@Pd0.1. The presence of Pd SACs (single atom catalysts) seems to be responsible for this performance. In contrast, the same Fe3O4dpa@Pd0.1 catalyst is absolutely inactive for the hydrogenation of styrene in ethanol.
- Guarnizo,Angurell,Muller,Llorca,Seco,Rossell,Rossell
-
-
Read Online
- Tandem intramolecular silylformylation and silicon-assisted cross-coupling reactions. Synthesis of geometrically defined α,β-unsaturated aldehydes
-
The palladium- and copper-catalyzed cross-coupling reactions of cyclic silyl ethers with aryl iodides are reported. Silyl ethers 3 were readily prepared by intramolecular silylformylation of homopropargyl silyl ethers 2 under a carbon monoxide atmosphere. The reaction of cyclic silyl ethers 3 with various aryl iodides 7 in the presence of [(allyl)PdCl]2, CuI, a hydrosilane, and KF·2H2O in DMF at room temperature provided the α,β-unsaturated aldehyde coupling products 8 in high yields. The need for copper in this process suggested that transmetalation from silicon to copper is an important step in the mechanism. Although siloxane 3 and the product 8 are not stable under basic conditions, KF·2H2O provided the appropriate balance of reactivity toward silicon and reduced basicity. The addition of a hydrosilane to [(allyl)PdCl]2 was needed to reduce the palladium(II) to the active palladium(0) form.
- Denmark, Scott E.,Kobayashi, Tetsuya
-
-
Read Online
- RHODIUM CATALYZED REDUCTION OF ARYL IODIDES WITH A MODEL OF NAD(P)H
-
Aryl iodides are reduced to the corresponding arenes with a model of NAD(P)H, 1-benzyl-1,4-dihydronicotinamide (BNAH), in the presence of a catalytic amount of rhodium complex.Nitro, carbonyl, and ester functions are inert under the condition.
- Yasui, Shinro,Nakamura, Kaoru,Ohno, Atsuyoshi
-
-
Read Online
- Recyclable and reusable Pd(OAc)2/PPh3/PEG-2000 system for homocoupling reaction of arylboronic acids under air without base
-
A stable and efficient Pd(OAc)2/PPh3/PEG-2000 catalytic system for homocoupling of arylboronic acids has been developed. In the presence of Pd(OAc)2 and PPh3, the homocoupling reaction of arylboronic acids was carried out smoothly in PEG-2000 at 70°C under air without base to afford a variety of symmetric biaryls in good to excellent yields. The isolation of the products was readily performed by extractionwith diethyl ether, and the Pd(OAc)2/PPh3/PEG-2000 systemcould be easily recycled and reused six times without significant loss of catalytic activity.
- Xia, Jianhui,Cheng, Mingzhu,Chen, Qiurong,Cai, Mingzhong
-
-
Read Online
- A new protocol for the one-pot synthesis of symmetrical biaryls
-
Biaryls play an important role in modern organic chemistry. Although a large number of protocols for the synthesis of symmetrical and unsymmetrical biaryls already exist, most of them are not generally applicable. In our studies toward the total synthesis of the secalonic acids, we were interested in bis(pinacolato)diboron as a reagent for transforming haloarenes into arylboronic esters. By optimizing the reaction conditions, we were able to obtain biaryls containing various functional groups in good to excellent yields.
- Nising, Carl F.,Schmid, Ulrike K.,Nieger, Martin,Braese, Stefan
-
-
Read Online
- Suzuki Coupling of Chiral 1,1′-Binaphthyl Systems - New Synthetic Routes to Functionalize the 2- and 2,2′-Positions
-
1,1′-Binaphthyl derivatives 1-5, substituted in the 2- or 2,2′-positions are used in palladium-catalyzed Suzuki coupling reactions. The mono- and bis-borylated coupling components 2, 4 and 5 can easily be prepared and purified, are air-stable and are therefore interesting starting materials for Suzuki coupling reactions with several aryl halides. Thus a variety of new axially-chiral 2- and 2,2′-arylated 1,1′-binaphthyls can be synthesized. Selective monoarylation of 3, 4 and 5 can be performed. Subsequent and stepwise arylation offers general access to unsymmetrically substituted binaphthyls. Moreover, interesting atropisomeric complex molecules, such as 4,4′-bis[2-(1,1′-binaphthyl)]-1,1′-biphenyl (18a), are accessible. Compounds of type 18, which can be obtained by twofold Pd-catalyzed coupling reactions, are of high potential value as ligands or promoters in catalytic, asymmetric processes or as chiral precursor molecules for host-guest interactions.
- Schilling, Birgit,Kaufmann, Dieter E.
-
-
Read Online
- Electroreductive palladium-catalysed Ullmann reactions in ionic liquids: Scope and mechanism
-
A room-temperature catalytic alternative to the Ullmann reaction is presented, based on electroreductive homocoupling of haloarenes catalysed by palladium naaoparticles. The particles are generated in situ in an electrochemical cell, and electrons are used to close the catalytic cycle and provide the motivating force for the reaction. This system gives good yields using iodo- and bromoarenes, and requires only electric current and water as reagents. Using an ionic liquid solvent combines the advantages of excellent conductivity and cluster stabilising. The solvent is reusable at least five times. Kinetic experiments at different electrode potentials show that the two-electron oxidation of water closes the catalytic cycle by regenerating the Pd(0). A mechanism involving radical anion formation is proposed. The advantages and limitations of this new system for carbon-carbon homocoupling and cross-coupling are discussed.
- Pachon, Laura Duran,Elsevier, Cornells J.,Rothenberg, Gadi
-
-
Read Online
- Icosahedral gold-platinum alloy nanocrystals in hollow silica: A highly active and stable catalyst for Ullmann reactions
-
Icosahedral Au-Pt alloy nanocrystals are prepared in porous hollow silica nanospheres via a hydrothermal method without using capping agents. These nanoparticles with unique shape and structure exhibit excellent catalytic activity and stability in Ullmann reactions. The Royal Society of Chemistry 2014.
- Wu, Xiaoli,Tan, Longfei,Chen, Dong,Meng, Xianwei,Tang, Fangqiong
-
-
Read Online
- Pd/TEMPO-catalyzed electrooxidative synthesis of biaryls from arylboronic acids or arylboronic esters
-
A facile electrooxidative method for synthesizing biaryls from arylboronic acids or arylboronic esters is described. In the presence of a catalytic amount of Pd(OAc)2 and TEMPO, the electrooxidation of arylboronic acids or arylboronates gave the corresponding biaryls in moderate to excellent yields.
- Mitsudo, Koichi,Shiraga, Takuya,Kagen, Daisuke,Shi, Deqing,Becker, James Y.,Tanaka, Hideo
-
-
Read Online
- The β-cyclodextrin decorated with palladium nanoparticles without pretreatment: An efficient heterogeneous catalyst for biaryls synthesis
-
β-Cyclodextrin decorated with palladium nanoparticles (PdNPs@β-CD) without pretreatment led to a suitable catalyst for the biaryls synthesis in water. A simple and straightforward method was developed for the preparation of PdNPs@β-CD as a green catalyst. The prepared catalyst was characterized by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS) measurements. It was found that PdNPs@β-CD exhibits high performance in Ullmann, Suzuki and Hiyama coupling reactions.
- Feiz, Afsaneh,Loni, Masood,Naderi, Soheila,Bazgir, Ayoob
-
-
Read Online
- A comparative homocoupling reaction of aryl halides using monomeric orthopalladated complex of 4-methoxybenzoylmethylenetri-phenylphosphorane under conventional and microwave irradiation conditions
-
The activity of [Pd(C6H4CH2NH 2-K2-C-N)PPh3MOBPPY]OTf complex, A (MOBPPY = 4-methoxybenzoylmethylenetriphenylphosphoraneylide) was investigated in the homocoupling reaction of a vast range of aryl halides under both conventional and microwave irradiation conditions and their results were compared. The complex was active and showed high efficiency in the formation of new C-C bonds. The yields were excellent using a catalytic amount of [Pd(C6H 4CH2NH2-K2-C-N)PPh 3MOBPPY]OTf complex in N, N-dimethylformamide at 120 °C. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times.
- Hajipour, Abdol R.,Karami, Kazem,Tavakoli, Ghazal
-
-
Read Online
- Pd-catalyzed oxidative homocoupling of arylboronic acids in aqueous ethanol at room temperature
-
The authors demonstrate for the first time that the Pd(OAc) 2/N,O-ligands act as catalysts toward homocoupling of arylboronic acid in aqueous ethanol (95%) under mild conditions: at room temperature and under aerobic condition. Under the optimal reaction conditions, all reactions gave the homocoupling products in good to excellent yields.
- Zhou, Zhonggao,Hu, Qiaosheng,Du, Ziyi,Xue, Jun,Zhang, Shiyong,Xie, Yongrong
-
-
Read Online
- Absolute Configuration Assignment from Optical Rotation Data by Means of Biphenyl Chiroptical Probes
-
A non-empirical approach for the assignment of the absolute configuration of chiral 2-alkyl-substituted carboxylic acids and primary amines by [α]D measurements has been developed. The method requires the conversion of the chiral acids or amines into the corresponding 4,4′-disubstituted biphenylamides or biphenylazepines, respectively. In these derivatives a central-to-axial chirality transfer induces a preferred torsion in the biphenyl moiety revealed by the sign of the biphenyl A band in the ECD spectrum. By 4,4′-substitution on the biphenyl moiety a redshift of the A band is obtained, leading to an increase of its relative contribution to optical rotation. This allows to reliably establish a direct correlation between the [α]D sign, the biphenyl twist and, then, the substrate absolute configuration. This approach thus constitutes a really practical and reliable method to assign the absolute configuration of chiral carboxylic acids and primary amines by simple and straightforward [α]D measurement, readily obtainable by a routine instrumentation like the polarimeter.
- Vergura, Stefania,Scafato, Patrizia,Belviso, Sandra,Superchi, Stefano
-
-
Read Online
- Cyclopalladated ferrocenylimine: a highly effective catalyst for the borylation/suzuki coupling reaction
-
The cyclopalladated ferrocenylimine was an efficient catalyst for the borylation/Suzuki coupling reaction. The catalytic loading for the reaction containing bromoarenes was 1 mol %. When iodobenzene was used, the catalytic loading was as low as 0.1 mol %. Furthermore, the cyclopalladated ferrocenylimine also exhibited excellent catalytic power in the case of substrates containing electron-donating substituents, with yields reaching 93% or higher.
- Ma, Ning,Zhu, Zhiwu,Wu, Yangjie
-
-
Read Online
- Synthesis of DMF-protected Au NPs with different size distributions and their catalytic performance in the Ullmann homocoupling of aryl iodides
-
DMF-stabilized Au nanoparticles (NPs) with three different particle sizes were prepared by controlling the reaction temperatures and times. In the absence of any additional ligands, these Au NPs showed high catalytic activity in the Ullmann homocoupling of aryl iodides in DMF. The effects of Au particle size on the coupling reaction were investigated by the use of three Au catalysts with mean particle sizes of ca. 1.0 nm, 2.5 nm, and 5.5 nm, respectively. The catalytic activity of the Au NPs was found to be in the order of Au (2.5 nm) > Au ( Au (5.5 nm), indicating that surface Au atoms do not have the same catalytic activity toward such a homocoupling reaction.
- Yao, Wang,Gong, Wei-Jie,Li, Hong-Xi,Li, Fei-Long,Gao, Jun,Lang, Jian-Ping
-
-
Read Online
- Investigation of the catalytic activity of a Pd/biphenyl-based phosphine system in the Ullmann homocoupling of aryl bromides
-
We described Ullmann homocoupling promoted by a Pd/biphenyl-based phosphine system using DMF as solvent. Using Hammett equation it is found that the rate determining step of the reaction depends on the electronic nature of substituents of aryl bromides. Increase the rate of reaction with decreasing the electron donating of the substituent from NH2 to H suggesting an oxidative addition step as the rate determining step. Decrease the rate of reaction with increasing the electron-withdrawing ability of the substituent from H to NO2 indicating a reductive elimination step as the rate determining step.
- Nadri, Shirin,Azadi, Ehsan,Ataei, Ali,Joshaghani, Mohammad,Rafiee, Ezzat
-
-
Read Online
- 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
-
-
Read Online
- Microwave assisted efficient protocol for the classic Ullmann homocoupling reaction using Cu-Mg-Al hydrotalcite catalysts
-
Four hydrotalcite catalysts containing different amounts of Cu and Mg cations, with varying atomic ratios of Cu:Mg:Al in the brucite-like layers of 0:2:1, 0.5:1.5:1, 1:1:1 and 2:0:1, were prepared by co-precipitation method. The synthesized catalysts were tested for classic Ullmann homocoupling of iodobenzene to produce biphenyl without using any stoichiometric amounts of base or reducing agent. The Mg-Al hydrotalcite catalyst without Cu ions is inactive, but the doping of Cu ions (Cu/Al = 0.5) into the Mg-Al hydrotalcite framework led to 63% conversion of iodobenzene under microwave irradiation. Gradual increase of Cu content and concomitant decrease of Mg content resulted in an increase in the conversion of iodobenzene and selectivity to biphenyl. The physico-chemical properties of hydrotalcite catalysts were studied by chemical analysis, XRD, FTIR, N2-physisorption, SEM, XPS, ESR and TPR techniques to understand the state of Cu ions presented in the hydrotalcite framework. It appears that presence of easily reducible isolated Cu2+ ions is essential to obtain improved performance of the catalyst.
- Narasimharao, Katabathini,Al-Sabban, Ebtisam,Saleh, Tamer S.,Gallastegui, Ainara Garcia,Sanfiz, Almudena Celaya,Basahel, Sulaiman,Al-Thabaiti, Shaeel,Alyoubi, Abdulrahman,Obaid, Abdullah,Mokhtar, Mohamed
-
-
Read Online
- One-pot two-step stannylation/Stille homocoupling of aryl bromides and iodides under solvent-free conditions
-
A new highly efficient solvent-free method for aryl bromide (iodide) homocoupling comprising the use of Pd(OAc)2/PCy3 system in the presence of CsF is suitable for substrates bearing functional groups not tolerant to lithium-, magnesium-, zincorganic reagents and strong bases.
- Gribanov, Pavel S.,Golenko, Yulia D.,Topchiy, Maxim A.,Philippova, Anna N.,Kirilenko, Nikita Yu.,Krivoshchapov, Nikolai V.,Sterligov, Grigorii K.,Asachenko, Andrey F.,Bermeshev, Maxim V.,Nechaev, Mikhail S.
-
-
Read Online
- Electrooxidative homo-coupling of arylboronic acids catalyzed by electrogenerated cationic palladium catalysts
-
An electrochemical method for generating cationic palladium complexes was integrated into an electrooxidative homo-coupling of arylboronic acids. In the presence of a catalytic amount of TEMPO, the homo-coupling reaction proceeded efficiently under argon to afford symmetric biaryls.
- Mitsudo, Koichi,Shiraga, Takuya,Tanaka, Hideo
-
-
Read Online
- Catalytic specificity of linear polystyrene-stabilized Pd nanoparticles during Ullmann coupling reaction in water and the associated mechanism
-
In the present work, heterogeneous Pd nanoparticle catalysts supported on linear polystyrene (PS-PdNPs) were used to promote Ullmann coupling reactions in water. The coupling reaction of 4-bromotoluene proceeded readily in the presence of methanol as the external reductant to give 4,4'-dimethylbiphenyl in 85% yield. In contrast, only a trace of the coupling product was obtained when using ethanol or 2-propanol. Higher yields were also observed for aryl bromides than for aryl iodides. The difference in the yields obtained from 4-iodotoluene and 4-bromotoluene is attributed to variations in the rate of reduction to reform Pd(0) species. The leaching of Pd species into the reaction medium has a negative effect on the Ullmann coupling reaction. The unique reactivity of PS-PdNPs and mechanistic pathway are discussed herein.
- Ohtaka, Atsushi,Sakon, Akira,Yasui, Asuka,Kawaguchi, Taira,Hamasaka, Go,Uozumi, Yasuhiro,Shinagawa, Tsutomu,Shimomura, Osamu,Nomura, Ry?ki
-
-
Read Online
- Facile construction of symmetric biaryls using (BeDABCO)2Pd2Cl6 as an efficient and highly active catalyst under microwave irradiation
-
An efficient catalytic system using (BeDABCO)2Pd2Cl6 (BeDABCO, benzyl-1,4-diazabicyclo[2.2.2]octane) was developed for the homo-coupling reaction of various aryl halides. Due to the combination of ionic homogeneous metal catalyst and microwave irradiation, symmetric biaryls were produced in excellent yields and short reaction times in N-methyl-2-pyrrolidone at 120 °C. BeDABCO as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species in this coupling reaction.
- Hajipour, Abdol Reza,Rafiee, Fatemeh
-
-
Read Online
- High thermal stability and rigid rod of novel organosoluble polyimides and polyamides based on bulky and noncoplanar naphthalene-biphenyldiamine
-
The synthesis of a naphthalene-substituted monomer, 2,2′- dinaphthylbiphenyl-4,4′-diamine, and its use in the preparation of soluble polyimides and polyamides by reaction of the diamine with commercial dianhydrides and dicarboxylic acids, was analyzed. IR spectra of synthesized monomers and polymers were recorded in the range 4000-500 cm-1 on a Jasco IR-700 spectrometer. The inherent viscosities of all polymers were measured using a Ubbelohde viscometer. The solubility, tensile properties, thermal properties, and dielectric constants of the obtained polyimides and polyamides were also investigated.
- Liaw, Der-Jang,Chang, Feng-Chyuan,Leung, Man-Kit,Chou, Meng-Yen,Muellen, Klaus
-
-
Read Online
- PALLADIUM CATALYZED REACTION OF HEXABUTYLDITIN WITH ARYL BROMIDES: PREPARATION OF NEGATIVELY SUBSITUTED ARYLTRIBUTYLTIN
-
Reaction of hexabutylditin with aryl bromides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium was found to be a promising tool to prepare aryltributyltins, particularly negatively substituted (-NO2, -COMe, -CN) phenyltin compounds.
- Kosugi, Masanori,Shimizu, Kohji,Ohtani, Atsushi,Migita, Toshihiko
-
-
Read Online
- Triazoliptycenes: A Twist on Iptycene Chemistry for Regioselective Cross-Coupling to Build Nonstacking Fluorophores
-
Triazoliptycene fluorophores have been designed and synthesized, in which a three-dimensional propeller-like iptycene motif is employed to suppress intermolecular π-π stacking in the solid state. Key to the success of this modular synthesis is a stereoelectronic bias imposed by the iptycene scaffold, which assists the desired regioselectivity in the C-N cross-coupling step as the last-stage structure diversification from a common precursor.
- Kang, Taewon,Kim, Hongsik,Lee, Dongwhan
-
-
Read Online
- Homocoupling of aryl halides promoted by tetrabutylammonium fluoride
-
The palladium-catalysed homocoupling of aryl halides takes place in the presence of anhydrous, in situ generated, tetrabutylammonium fluoride (TBAF).
- Albanese, Domenico,Landini, Dario,Penso, Michele,Petricci, Silvia
-
-
Read Online
- Palladium and copper-catalyzed ligand-free coupling of phenylhydrazines in water
-
An efficient protocol has been developed for the synthesis of biaryls via Pd/Cu catalyzed coupling of phenylhydrazines in water. Homo and cross couplings were successfully achieved in a ligand-free catalytic system, at room temperature with water as sole reaction medium. This journal is
- Chauhan, Parul,Ravi, Makthala,Singh, Shikha,Raju, Kanumuri S. R.,Bajpai, Vikas,Kumar, Brijesh,Wahajuddin,Yadav, Prem. P.
-
-
Read Online
- Zeolite-assisted nitration of biphenyl using nitric acid
-
The nitration process using 95 % nitric acid instead of the classical nitric acid-sulfuric acid system appears to be attractive and promising in the preparation of nitro compounds. The ratio of 2-nitrobiphenyl (2a) isomer to 4-nitrobiphenyl (2b) can reach 0.69 in a good yield of 78.42 %. The isomeric distribution of the product mononitrobiphenyl was found to be superior to traditional methods. Raising the ratio of 95 % nitric acid and biphenyl to 4:1, the yield of dinitration products can reach more than 78.08 %, as a mixture of 2,2-dinitrobiphenyl (3a), 2,4-dinitrobiphenyl (3b), and 4,4-dinitrobiphenyl (3c).
- Tai, Yanfang,Peng, Xinhua,Shi, Chunjie,Dong, Xiongzi
-
-
Read Online
- Efficient and high turnover homocoupling reaction of aryl iodide by the use of palladacycle catalyst. A convenient way to prepare poly-p-phenylene
-
Monoiodoarenes undergo reductive coupling to produce biaryls in high yields in the presence of less than 0.1 mol % of palladacyle and N,N- diisopropylethylamine in DMF at 100°C. Under similar reaction conditions, p- diiodobenzene produces poly-p-phenylene in greater than 85% isolated yields.
- Luo, Fen-Tair,Jeevanandam, Arumugasamy,Basu, Manas Kumar
-
-
Read Online
- 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)
-
- 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.
-
-
- 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
-
-
- Valorisation of urban waste to access low-cost heterogeneous palladium catalysts for cross-coupling reactions in biomass-derived γ-valerolactone
-
Herein we report a simple protocol for the valorisation of a common urban biowaste. The lignocellulosic biomass obtained after the pre-treatment of pine needle urban waste is efficiently transformed into a low-cost support (PiNe) for the immobilization of Pd nanoparticles. The final Pd/PiNe heterogeneous catalyst features a small particle size (4.5 nm) and a metal loading (9.9 wt%) comparable with most commercially available and generally used counterparts. In this contribution, we tested the catalytic efficiency of the Pd/PiNe system in two representative cross-couplings, Heck and Hiyama reactions, and compared the results obtained with commercial Pd/C catalyst. The good reactivity in the biomass-derived solvent (GVL) confirms that the Pd/PiNe heterogeneous catalyst is a valid system that can be integrated into a waste valorization chain within a circular economy approach. In addition, the efficiency of the catalyst has also been extended to perform the challenging consecutive Hiyama-Heck reaction to afford differently substituted (E)-1,2-diarylethenes.
- Valentini, Federica,Ferlin, Francesco,Lilli, Simone,Marrocchi, Assunta,Ping, Liu,Gu, Yanlong,Vaccaro, Luigi
-
p. 5887 - 5895
(2021/08/23)
-
- Synthesis and reactivity of α-sulfenyl-β-chloroenones, including oxidation and Stille cross-coupling to form chalcone derivatives
-
The synthesis of a range of novel α-sulfenyl-β-chloroenones from the corresponding α-sulfenylketones, via a NCS mediated chlorination cascade, is described. The scope of the reaction has been investigated and compounds bearing alkyl- and arylthio substituents have been synthesised. In most instances, the Z α-sulfenyl-β-chloroenones were formed as the major products, while variation of the substituent at the β-carbon position led to an alteration in stereoselectivity. Stille cross-coupling with the Z α-sulfenyl-β-chloroenones led to selective formation of Z sulfenyl chalcones, while the E α-sulfenyl-β-chloroenones did not react under the same conditions. Oxidation of the Z α-sulfenyl-β-chloroenones was followed by isomerisation, leading to the E α-sulfinyl-β-chloroenones. Stille cross-coupling with the E α-sulfinyl-β-chloroenones produced the E sulfinyl chalcones. Either the E or Z sulfinyl chalcones can be obtained by altering the sequence of oxidation and Stille cross-coupling.
- Kearney, Aoife M.,Murphy, Linda,Murphy, Chloe C.,Eccles, Kevin S.,Lawrence, Simon E.,Collins, Stuart G.,Maguire, Anita R.
-
supporting information
(2021/05/04)
-
- 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)
-
- 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
-
-
- Copper catalysed Gomberg-Bachmann-Hey reactions of arenediazonium tetrafluoroborates and heteroarenediazonium o-benzenedisulfonimides. Synthetic and mechanistic aspects
-
Gomberg-Bachmann-Hey reactions were carried out in the presence of copper as a catalyst and gave rise to biaryls or heterobiaryls in good yields and in mild reaction conditions. A computational study of some key points of the reaction was performed. The results are coherent with the experimental data and confirm some aspects of the mechanism. The reaction free energies for the reduction in benzene by CuI of a set of 40 (hetero)arenediazonium tetrafluoroborates were calculated. Both the experiments and the calculations showed that in the coupling with substituted solvents (toluene, bromobenzene, nitrobenzene and anisole) the binding to the ortho position was always favoured.
- Antenucci, Achille,Barbero, Margherita,Dughera, Stefano,Ghigo, Giovanni
-
-
- 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
-
-
- DIAMINE COMPOUND, POLYIMIDE PRECURSOR AND POLYIMIDE FILM PREPARED BY USING SAME
-
The present invention discloses a novel diamine having a structure including an intramolecular imide group while having an aromatic ring group with a rigid structure. In addition, and by comprising the novel diamine as a polymerization component, the present invention can provide a polyimide film having improved mechanical and thermal properties while maintaining optical properties of polyimide.
- -
-
Paragraph 0250-0252
(2020/09/26)
-
- DIAMINE COMPOUND, AND POLYIMIDE PRECURSOR AND POLYIMIDE FILM PREPARED BY USING THE SAME
-
The present invention disclosed a novel diamine compound including a structure in which a phenylene linker (L) connecting an intramolecular imide ring and the imide ring is bonded to a phenyl ring substituted with -NH-(C=O)- or -O-(C=O)-. A polyimide film prepared by polymerizing the novel diamine compound has not only improved mechanical and thermal properties, but also an excellent refractive index.COPYRIGHT KIPO 2021
- -
-
Paragraph 0197-0200; 0358-0361
(2020/11/03)
-
- Exploring the coordination confinement effect of divalent palladium/zero palladium doped polyaniline-networking: As an excellent-performance nanocomposite catalyst for C-C coupling reactions
-
A pre-formed catalyst Pd2+/PANI composite for C-C coupling reaction was synthesized by combining the self-stabilized dispersion polymerization method with the in-situ composite material. Experiments have confirmed that the relatively high reduced structure (75%) in the polyaniline carrier is more favorable for the coupling reaction. Raman spectroscopy, solid nuclear magnetic, and X-ray photoelectron spectroscopy were performed to characterize the structures. The pre-formed catalyst has uniform coordination of divalent palladium and nitrogen in different valence states of the carrier polyaniline, which shows a good synergistic effect in the catalytic Ullmann reaction, and greatly reduces the use of reducing agents such as hydrazine hydrate. Compared with other studies, we analyzed the catalytic reaction mechanism in detail through real-time online infrared and XPS characterization. The results show that the divalent palladium in the catalyst and the zero-valent palladium generated by the in-situ reaction synergistically promote the reaction, while the polyaniline support acts as a stabilizer and dispersant, which prevents the agglomeration of the metal particles and prolongs increased catalyst life. The prepared Pd2+/PANI composites will become the most attractive alternative to traditional organic materials due to their wide applicability, high catalytic activity, stable recycling and relatively low price. This work provides a new theoretical basis for the understanding of the essential driving force of PANI catalytic activity and the cognition of the micro mechanism of action.
- Liang, Yanping,Liu, Wanyi,Song, Manrong,Sun, Yanyan,Wang, Gang,Wu, Zhiqiang,Zhan, Haijuan
-
p. 177 - 188
(2020/03/17)
-
- Palladium/Sensory Component-Catalyzed Homocoupling Reactions of Aryl Halides
-
A novel and efficient catalyst system was developed for homocoupling reactions of aryl halides. The catalyst system consists of Pd(OAc) 2and the peppery sensory component of tobacco leaves. This is the first time that a sensory component has been used in an organic reaction. Experiments using the catalyst system showed that the reactions proceeded smoothly under air in the absence of both an additional ligand and a reductant. Furthermore, the catalyst system can be applied to the coupling reactions of hetaryl iodides. Many functional groups (including a hydroxy group) are tolerated.
- Bai, Haixin,Bao, Fengyu,Chai, Guobi,Liu, Pengfei,Liu, Zhikai,Zhang, Haiyan,Zhang, Qidong
-
supporting information
(2020/09/09)
-
- Sulphonic acid functionalized porphyrin anchored with a: Meso -substituted triazolium ionic liquid moiety: A heterogeneous photo-catalyst for metal/base free C-C cross-coupling and C-N/C-H activation using aryl chloride under visible light irradiation
-
We report an easy process to synthesize sulphonic acid functionalized porphyrin, anchored with a meso-substituted triazolium ionic liquid moiety (SAFPTILM) for metal/base free C-C cross-coupling and C-N/C-H activation using aryl chloride under visible light irradiation. The acid strength has been measured based on the Hammett indicator. The SAFPTILM photocatalyst comprising 18 π-conjugated electronic systems with the chromophore substituents in the meso-position can provide rapid electronic conducting channels during photocatalysis under the irradiation of visible light. It was found that SAFPTILM is an efficient photocatalyst for the Heck, Sonogashira, Buchwald, Ullmann/Fittig coupling and C-H activation of phenols with different aryl chlorides in the absence of a base/noble metal, using 5 W LED (yellow) light under ambient conditions. The photocatalyst with low band gap (1.55 eV) comprising conjugation, favors coupling reaction of unactivated aryl chlorides, by easy excitation of electrons and transfer to the conjugated benzimidazolium based phenylenediamine support delaying the recombination of photoinduced electron-hole pairs.
- Bhansali, Karan,Raut, Subodh,Barange, Shital,Bhagat, Pundlik
-
p. 19690 - 19712
(2020/12/04)
-
- 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)
-
- Glucopyranoside-substituted imidazolium-based chiral ionic liquids for Pd-catalyzed homo-coupling of arylboronic acids in water
-
Chiral ionic liquids (CILs) are widely used solvents and materials with prominent properties. Carbohydrate-derived imidazolium-based CILs represent a distinctive type of CILs possessing multiple chiral centers from natural chiral pool. Herein, a series of glucopyranoside-substituted imidazolium-based CILs (Glu-imi-CILs) were synthesized and evaluated as ligands for Pd-catalyzed homo-coupling reactions of arylboronic acids in water. The glucopyranoside substituent was instrumental for improving the catalytic activity of the resulting catalysts. Moreover, a Glu-imi-CIL with a free hydroxyl group for additional coordination was found to be the most efficient ligand. A series of symmetric biaryl compounds (13 examples) were synthesized from arylboronic acids by this method in high isolated yields (85?99percent).
- Huang, Zhiqiang,Kong, Lingfang,Li, Jing,Wu, Yue,Xue, Jun,Yuan, Yangyang,Zhou, Zhonggao
-
-
- Efficient Pd-catalyzed oxidative homocoupling of arylboronic acids in aqueous NaClO
-
An efficient, mild and practical method was developed for the synthesis of biaryls via the Pd-catalyzed oxidative homocoupling of aromatic/heteroaromatic boronic acids in aqueous NaClO.
- Li, Min-Xin,Tang, Yan-Ling,Gao, Hui,Mao, Ze-Wei
-
supporting information
(2020/03/04)
-
- L -(-) -Quebrachitol as a Ligand for Selective Copper(0)-Catalyzed N-Arylation of Nitrogen-Containing Heterocycles
-
l-(-)-Quebrachitol (QCT) has been found as a ligand of copper powder for selective N-arylation of nitrogen-containing heterocycles with aryl halides. Furthermore, another potential catalytic system (copper powder/QCT/t-BuOK) was successfully adapted to unactivated aryl chlorides.
- Zhou, Qifan,Du, Fangyu,Chen, Yuanguang,Fu, Yang,Sun, Wenjiao,Wu, Ying,Chen, Guoliang
-
p. 8160 - 8167
(2019/06/28)
-
- Synthesis, structure, and synthetic potential of arenediazonium trifluoromethanesulfonates as stable and safe diazonium salts
-
Aromatic diazonium salts are valuable building blocks for organic synthesis; however, in most cases, they are unstable, unsafe, poorly soluble, and/or expensive. In this paper, we have shown that a variety of stable and safe arenediazonium triflates ArN2+ TfO– can be obtained easily and in high yields by diazotization of anilines with tert-butyl nitrite in the presence of trifluoromethanesulfonic acid. Arenediazonium triflates are relatively shelf-stable in the dry state. They dissolve well in water, as well as polar and even nonpolar organic solvents. Less than 800 J/g of energy is released during the thermal decomposition of these salts, which indicates their explosion safety. Arenediazonium triflates have a high reactivity in the known reactions of diazonium chemistry, and undergo an unusual metal-free chlorodediazonization reaction with chloroform and CCl4.
- Filimonov, Victor D.,Krasnokutskaya, Elena A.,Kassanova, Assia Zh.,Fedorova, Valentina A.,Stankevich, Ksenia S.,Naumov, Nikolay G.,Bondarev, Alexander A.,Kataeva, Veronika A.
-
p. 665 - 674
(2018/09/14)
-
- A comparative study on NHC-functionalized ternary Se/Te-Fe-Cu compounds: Synthesis, catalysis, and the effect of chalcogens
-
A novel family of N-heterocyclic carbene (NHC)-incorporated Se-Fe-Cu compounds, bis-1,3-dimethylimidazol-2-ylidene (bis-Me2-imy)-containing compound [(μ4-Se)Fe3(CO)9{Cu(Me2-imy)}2] (2), bis-N-methyl- or bis-N-isopropyl-substituted benzimidazol-2-ylidene (bis-Me2-bimy or bis-iPr2-bimy)-incorporated compounds [(μ4-Se)Fe3(CO)9{Cu(Me2-bimy)}2] (3) or [(μ4-Se)Fe3(CO)9{Cu(iPr2-bimy)}2] (4), and a bis-1,3-dimethyl-4,5-dichloroimidazol-2-ylidene (bis-Me2-Cl2-imy)-containing compound [(μ3-Se)Fe3(CO)9{Cu(Me2-Cl2-imy)}2] (5), were synthesized in moderate yields in facile one-pot reactions of the ternary pre-designed compound [(μ3-Se)Fe3(CO)9{Cu(MeCN)}2] (1) with the corresponding imidazolium salts and KOtBu in THF in an ice-water bath. Single-crystal X-ray analyses revealed that the Me2-imy compound 2 or the Me2-bimy compound 3 each exhibited a trigonal bipyramidal SeFe3(CO)9Cu geometry with an Fe2Cu plane further capped by a Cu(Me2-imy) or Cu(Me2-bimy) fragment, respectively, with one long Cu-Cu covalent bond. In addition, compound 4 also comprised a trigonal bipyramidal SeFe3(CO)9Cu core structure, but the second Cu(iPr2-bimy) group bridged the equatorial Fe-Fe edge with two unbonded Cu atoms, due to the presence of a sterically bulky iPr2-bimy fragment. On the other hand, the strong electron-withdrawing chloro-containing NHC compound 5 showed a comparatively open tetrahedral SeFe3(CO)9 metal core, where two Fe-Fe edges each were further bridged by a Cu(Me2-Cl2-imy) fragment. Due to the nonclassical C-H?O(carbonyl) hydrogen bonds between the CO groups of the SeFe3(CO)9Cu2 core and CH moieties of the neighboring NHC ligands, both compounds 2 and 3 comprised a one-dimensional network, while compounds 4 and 5 each were made up of a two-dimensional framework in the solid state, which efficiently enhanced the stability of these Se-Fe-Cu NHC compounds. Importantly, all of these synthesized Se-Fe-Cu NHC compounds 2-5 had pronounced catalytic activities for the homocoupling of arylboronic acids with high catalytic yields. Finally, these Se-containing Fe-Cu NHC compounds further represented excellent models for studying chalcogen effects in comparison to their Te analogs, as demonstrated by their catalytic performances and electrochemical behaviors, and by DFT calculations.
- Shieh, Minghuey,Liu, Yu-Hsin,Wang, Chih-Chin,Jian, Si-Huan,Lin, Chien-Nan,Chen, Yen-Ming,Huang, Chung-Yi
-
p. 11832 - 11843
(2019/08/07)
-
- Multifunctional Tubular Organic Cage-Supported Ultrafine Palladium Nanoparticles for Sequential Catalysis
-
The imine condensation reaction of 5,5′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diisophthalaldehyde with cyclohexanediamine resulted in a shape-persistent multifunctional tubular organic cage (MTC1). It exhibits selective fluorescence sensing towards divalent Pd ions with a very low detection limit (38 ppb), suggesting effective complexation between these two species. Subsequent reduction of MTC1 and Pd(OAc)2 with NaBH4 afforded a cage-supported catalyst with well-dispersed ultrafine Pd nanoparticles (NPs) in a narrow size distribution (1.9±0.4 nm), denoted as Pd?MTC1-1/5. Such ultrafine Pd NPs in Pd?MTC1-1/5, in cooperation with photocatalytically active MTC1, enable efficient sequential reactions involving visible light-induced aerobic hydroxylation of 4-nitrophenylboronic acid to 4-nitrophenol and the following hydride reduction with NaBH4. This is the first example of a multifunctional organic cage capable of sensing, directing nanoparticle growth, and catalyzing sequential reactions.
- Sun, Nana,Wang, Chiming,Wang, Hailong,Yang, Le,Jin, Peng,Zhang, Wei,Jiang, Jianzhuang
-
supporting information
p. 18011 - 18016
(2019/11/14)
-
- Homocoupling of arylboronic acids catalyzed by dinuclear copper(I) complexes under mild conditions
-
An efficient protocol for C–C coupling has been developed using three iodo-bridged copper(I) complexes as catalysts. Complexes [CuI(bpy)]2 (1), [CuI(phen)]2·DMF (2), and [CuI(Mephen)]2 (3) were successfully synthesized via solvothermal method (bpy = 2,2′-dipyridyl, phen = 1,10-phenanthroline, and Mephen = 2,9-dimethylphenanthroline). The self-coupling reaction of phenylboronic acid was selected as a model reaction to evaluate the catalytic property of the complexes. Moreover, this method tolerates various substituents on the arylboronic acids such as halogens, carbonyls, and nitro groups. It shows that the iodo-bridged Cu(I) center serves as the active site to activate molecular oxygen during the catalytic process. The result illustrates that these complexes were found to be excellent catalysts for self-coupling of arylboronic acids under mild conditions.
- Long, Bing-Fan,Qin, Gui-Fang,Huang, Qin,Xiong, Ting,Mi, Yan,Hu, Fei-Long,Yin, Xian-Hong
-
p. 2639 - 2646
(2019/07/17)
-
- Palladium Niacin Complex Immobilized on Starch-Coated Maghemite Nanoparticles as an Efficient Homo- and Cross-coupling Catalyst for the Synthesis of Symmetrical and Unsymmetrical Biaryls
-
Abstract: In this work, catalytic efficiency of palladium niacin complex immobilized on starch-coated maghemite nanoparticles successfully exploited for homo- and cross-coupling reactions such as Suzuki–Miyaura, Sonogashira-, and Ullmann coupling reactions. The solid catalyst characterized by different methods such as FT-IR, TGA, XPS, EDS and ICP-AES. TEM images revealed a nanosize structure for catalyst and vibrating sample magnetometer (VSM) demonstrated its magnetic property. The reactions proceeded well in the absence of commonly used additives with high selectivity. Potential reusability of magnetically separable palladium catalyst and performing the reactions at environmentally conditions are notable features of the present methods making great potential for practical applications. Graphical Abstract: [Figure not available: see fulltext.].
- Rezapour, Elham,Jafarpour, Maasoumeh,Rezaeifard, Abdolreza
-
p. 3165 - 3177
(2018/08/22)
-
- WEPA: a bio-derived medium for added base, π-acid and ligand free Ullmann coupling of aryl halides using Pd(OAc)2
-
A bio-derived sustainable medium based on water extract of pomegranate ash (WEPA) has, for the first time, been developed for the homocoupling of aryl halides under palladium-assistance. Avoiding the requirement of an external base, ligand and π-acid, the use of the proposed renewable medium offers remarkable attributes like wide substrate scope, good to nearly quantitative yields of biphenyls with exceptional chemoselectivity and scale up viability.
- Lakshmidevi, Jangam,Appa, Rama Moorthy,Naidu, Bandameeda Ramesh,Prasad, S. Siva,Sarma, Loka Subramanyam,Venkateswarlu, Katta
-
supporting information
p. 12333 - 12336
(2018/11/30)
-
- Immobilization of an Aminobisphosphine–PdII Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki–Miyaura, Ullmann Coupling and Cyanation Reactions
-
The grafting of an aminobis(phosphine)–PdII complex (PNP–PdII) [PdCl2{(Ph2P)2N(CH2)3Si(OMe)3}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy, solid-state 31P NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki–Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP–PdII shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.
- Sengupta, Debasish,Pandey, Madhusudan K.,Mondal, Dipanjan,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
-
p. 3374 - 3383
(2018/05/08)
-
- Gold catalysed Suzuki-Miyaura coupling of arenediazonium o-benzenedisulfonimides
-
Arenediazonium o-benzenedisulfonimides have been used as efficient electrophilic partners in Au(I) catalysed Suzuki coupling reactions. The synthetic protocol is general, easy and produced either biaryls or heteroaryl arenes in good yields (51 positive examples, average yield 80%). o-Benzenedisulfonimide was recovered at the end of the reactions and was reused to prepare the starting salts for further reactions. Mechanistic insights suggest that the o-benzenedisulfonimide anion act as an electron transfer agent and promotes a catalytic cycle which does not require the presence of photocatalysts or external oxidants.
- Barbero, Margherita,Dughera, Stefano
-
p. 5758 - 5769
(2018/09/10)
-
- Oxidative and Reductive Cross-Coupling Reactions Catalyzed by an Anionic "ligandless" Palladium Complex
-
The anionic complex [NBu4][Pd(DMSO)Cl3], which can be synthesized on a gram scale in a single step starting from commercially available starting materials, has been shown to be an active catalyst in the Mizoroki-Heck reaction of aryl halides. We present two new catalytic applications of this complex: the base-free oxidative Heck reaction and the reductive homodimerization of aryl halides. This complex outperformed other palladium salts. In the latter reaction, the catalyst loading could be reduced to 0.01 mol %. The scope of the reactions has been explored, demonstrating the potential of the anionic palladium complex in these catalytic transformations.
- Schroeter, Felix,Lerch, Swantje,Strassner, Thomas
-
supporting information
p. 1614 - 1621
(2019/01/04)
-
- An Active Palladium Colloidal Catalyst for the Selective Oxidative Heterocoupling of (Hetero)Aryl Boronic Acids
-
A highly selective oxidative heterocoupling protocol for (hetero)aryl boronic acids with an active palladium colloidal catalyst was developed. The judicious choice of electronically different aryl boronic acids made possible such couplings under mild conditions, with air as oxidant, while embracing a wide substrate scope. This successful approach further allowed the development of a unique one-pot sequential oxidative heterocoupling/Suzuki–Miyaura cross-coupling tandem process for accessing substituted terphenyls.
- Sable, Vaibhav,Maindan, Karan,Bhilare, Shatrughn,Chrysochos, Nicolas,Schulzke, Carola,Kapdi, Anant R.
-
supporting information
p. 2489 - 2498
(2018/09/10)
-
- Integrating Organic Lewis Acid and Redox Catalysis: The Phenalenyl Cation in Dual Role
-
In recent years, merging different types of catalysis in a single pot has drawn considerable attention and these catalytic processes have mainly relied upon metals. However, development of a completely metal free approach integrating organic redox and organic Lewis acidic property into a single system has been missing in the current literature. This study establishes that a redox active phenalenyl cation can activate one of the substrates by single electron transfer process while the same can activate the other substrate by a donor-acceptor type interaction using its Lewis acidity. This approach has successfully achieved light and metal-free catalytic C-H functionalization of unactivated arenes at ambient temperature (39 entries, including core moiety of a top-selling molecule boscalid), an economically attractive alternative to the rare metal-based multicatalysts process. A tandem approach involving trapping of reaction intermediates, spectroscopy along with density functional theory calculations unravels the dual role of phenalenyl cation.
- Ahmed, Jasimuddin,Chakraborty, Soumi,Jose, Anex,Sreejyothi,Mandal, Swadhin K.
-
supporting information
p. 8330 - 8339
(2018/06/19)
-
- Gold catalyzed Heck-coupling of arenediazonium o-benzenedisulfonimides
-
Diazonium salts, and precisely arenediazonium o-benzenedisulfonimides, have been used for the first time as efficient electrophilic partners in gold catalyzed Heck-coupling reactions. The synthetic protocol was general, easy and gave the target products in satisfactory yields. Mechanistic insights revealed the fundamental roles of the o-benzenedisulfonimide anion as an electron transfer agent thath promotes a radical pathway that does not require the presence of photocatalysts or external oxidants.
- Barbero, Margherita,Dughera, Stefano
-
p. 295 - 301
(2018/01/12)
-
- Palladium nanocatalysts in glycerol: Tuning the reactivity by effect of the stabilizer
-
Palladium nanoparticles (PdNPs) prepared in neat glycerol containing TPPTS (tris(3-sulfophenyl)phosphine trisodium salt) or cinchona-based alkaloids (cinchonidine, quinidine) as capping agents, were applied as catalysts in fluoride-free Hiyama couplings and conjugate additions with the aim of evaluating the influence of the stabilizer in the catalytic reactivity. Therefore, PdNPs stabilized by phosphine favored C–C cross-couplings, whereas those containing alkaloids showed enhanced suitability for C–C homo-couplings and conjugate additions. The metal/stabilizer coordination mode, i.e. Pd–P dative bond and π-π interaction between quinoline moiety and palladium surface, is certainly key for the stabilization of different active metallic species and then promoting distinctive catalytic pathways.
- Reina, Antonio,Serrano-Maldonado, Alejandro,Teuma, Emmanuelle,Martin, Erika,Gómez, Montserrat
-
-
- Bimetallic Au-Pd nanochain networks: Facile synthesis and promising application in biaryl synthesis
-
A simple and facile method is described for the morphology-controlled synthesis of bimetallic Au-Pd alloyed nanochain networks (NNCs) that show high catalytic performance for the Ullmann intermolecular homocoupling of aromatic or alkyl halides (X = I, Br, Cl) in aqueous media and can be reused at least five times, which can also be applied to intramolecular homocoupling.
- Wang, Zheng-Jun,Wang, Xia,Lv, Jing-Jing,Feng, Jiu-Ju,Xu, Xinhua,Wang, Ai-Jun,Liang, Zhiwu
-
p. 3894 - 3899
(2017/07/12)
-
- Palladium(II) complexes with diaminomaleonitrile-based Schiff-base ligands: Synthesis, characterization and application as Suzuki–Miyaura coupling catalysts
-
The characterization of synthesized Schiff base ligands (L1–L5); (where L1?=?N-salicyliden- 2,3-diamino-cis-2-butenedinitrile, L2?=?3- methoxy-N-salicyliden-2,3-diamino-cis-2-butenedinitrile, L3?=?5-bromo-N-salicyliden-2,3-diamino-cis-2-butenedinitrile, L4?=?5-nitro-N-salicyliden-2,3-diamino-cis-2-butenedinitrile, and L5?=?5-methoxy-N-salicyliden-2,3-diamino-cis-2-butenedinitrile) and their palladium complexes [PdL(PPh3)] (L1–L5) were carried out by FT-IR, UV–vis, 1H NMR, 13C NMR and elemental analysis. The coordination geometry of [PdL3(PPh3)] was determined by single crystal X-ray crystallography. In this structure the palladium center was in a partially distorted NNOP square planar coordination environment. The catalytic potential of the synthesized complexes was evaluated in Suzuki–Miyaura cross-coupling reaction by choosing different arylhalides and phenylboronic acid. The results showed that arylhalides with electron withdrawing substituents were more appropriate in this reaction. In all cases, the desired product of cross coupling Suzuki reaction was the major product. It is also worth to mention that the product of homo-coupling reaction was also observed as a minor product. In this regards, a blank reaction with just phenylboronic acid was performed and the results showed the occurrence of the homo-coupling product in a good yield.
- Beigi, Zeinab,Kianfar, Ali Hossein,Mohammadnezhad, Gholamhossein,G?rls, Helmar,Plass, Winfried
-
-
- Heck arylation of allyl alcohol catalyzed by Pd(0) nanoparticles
-
Pd(0) nanoparticles ca. 2 nm in diameter were obtained by the reduction of PdCl2 and Pd(OAc)2 in water at 80 °C in the presence of a PVP-stabilizing polymer. Pd(0) NPs were successfully used in the Heck coupling of allyl alcohol with iodo- and bromobenzenes. Iodobenzenes reacted under solventless conditions or in DMF solution producing 3-arylpropanals and 2-arylpropanals as the main products. The same products were obtained in the reaction of bromobenzene in TBAB as the reaction medium. The stability of Pd(0) NPs was evidenced in recycling experiments. Similar Heck coupling results were also obtained with the palladium compounds PdCl2(cod) and Pd(OAc)2 under the same conditions.
- Tarnowicz, Stanis?awa,Alsalahi, Waleed,Mieczyńska, Ewa,Trzeciak, Anna M.
-
p. 5605 - 5612
(2017/08/26)
-
- Palladium-catalyzed reductive homocoupling of aryl sulfonates via cleavage of C─O bond at room temperature
-
Palladium-catalyzed reductive homocoupling of aryl sulfonates has been successfully achieved under mild conditions. This transformation is a new method for the homocoupling reaction of aryl sulfonates at room temperature via the cleavage of C─O bonds, thus providing an alternative synthesis of symmetric biaryls. The reported reductive homocoupling reaction is tolerant of many common functional groups regardless of electron-donating or electron-withdrawing nature, making this newly developed transformation important for complementing Ullmann coupling. Experimental Section. Typical procedure for the products.
- Zhong, Shuangling,Chen, Mengxin,Liu, Ge,Sun, Chenggang,Liu, Wencong
-
-
- Consecutive one-pot versus domino multicomponent approaches to 3-(Diarylmethylene)oxindoles
-
Based on consecutive one-pot conditions combining three palladium-catalyzed reactions (Sonogashira, Heck and Suzuki-Miyaura reactions), a more efficient domino multicomponent method has been successfully developed to access a wide variety of 3-(diarylmethylene)oxindoles. Microwave irradiation and use of a silver salt were the most important factors to achieve high yields and stereoselectivity.
- Park, Sunhwa,Lee, Jiyun,Shin, Kye Jung,Oh, Euichaul,Seo, Jae Hong,Bunce, Richard A.
-
-
- Miyaura Borylation and One-Pot Two-Step Homocoupling of Aryl Chlorides and Bromides under Solvent-Free Conditions
-
Solvent-free protocols for Miyaura borylation and the one-pot, two-step homocoupling of aryl halides are reported for the first time. Bis(dibenzylideneacetone)palladium(0) [Pd(dba)2] is an optimal source of palladium for Miyaura borylation, while for one-pot two-step homocoupling palladium(II) acetate [Pd(OAc)2] gives highest yields. Aryl bromides are coupled most efficiently using the DPEphos ligand. Chlorides are coupled using XPhos. The developed protocols are robust, versatile and easily reproducible on a large scale.
- Dzhevakov, Pavel B.,Topchiy, Maxim A.,Zharkova, Daria A.,Morozov, Oleg S.,Asachenko, Andrey F.,Nechaev, Mikhail S.
-
p. 977 - 983
(2016/04/05)
-
- A modified Cu(0)-Cu(I)-mediated Caryl-CarylUllmann coupling for the synthesis of biaryls
-
A novel Cu(0)-Cu(I)-mediated Caryl-CarylUllmann coupling has been successfully developed. The use of Cu(I) salts allowed the reactions to proceed under relatively mild conditions (65?°C in DMSO for 15–72?h). The developed method was compatible with a relatively wide range of functional groups simultaneously present on the aromatic ring of different electronic nature. The aryl halides with an electron-withdrawing group ortho to the halide or an electron-donating group meta or para to the halide furnished the corresponding products in good to excellent yields (up to 98%).
- Yasamut, Kittisak,Jongcharoenkamol, Jira,Ruchirawat, Somsak,Ploypradith, Poonsakdi
-
p. 5994 - 6000
(2016/09/14)
-