- Preparation of metal-immobilized methacrylate-based monolithic columns for flow-through cross-coupling reactions
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With the aim of developing efficient flow-through microreactors for high-throughput organic synthesis, in this work, microreactors were fabricated by chemically immobilizing palladium-, nickel-, iron-, and copper-based catalysts onto ligand-modified poly(glycidyl methacrylate-co-ethylene dimethacrylate) [poly(GMA-co-EDMA)] monoliths, which were prepared inside a silicosteel tubing (10 cm long with an inner diameter of 1.0 mm) and modified with several ligands including 5-amino-1,10-phenanthroline (APHEN), iminodiacetic acid (IDA), and iminodimethyl phosphonic acid (IDP). The performance of the resulting microreactors in Suzuki?Miyaura cross-coupling reactions was evaluated, finding that the poly(GMA-co-EDMA) monolith chemically modified with 5-amino-1,10-phenanthroline as a binding site for the palladium catalyst provided an excellent flow-through performance, enabling highly efficient and rapid reactions with high product yields. Moreover, this monolithic microreactor maintained its good activity and efficiency during prolonged use.
- Sabarudin, Akhmad,Shu, Shin,Umemura, Tomonari,Yamamoto, Kazuhiro
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- PREPARATION OF DIPHENYL COMPOUNDS
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This disclosure relates to the preparation of diphenyl compounds, especially dimethylbiphenyl compounds, in which there is one methyl group on each ring, and their oxidized analogues. These compounds, and particularly alkylated biphenyl compounds and biphenylcarboxylic acids, alcohols and esters, are useful intermediates in the production of a variety of commercially valuable products, including polyesters and plasticizers for PVC and other polymer compositions.
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Paragraph 0040
(2019/10/29)
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- OXIDATION OF METHYL-SUBSTITUTED BIPHENYL COMPOUNDS
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A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt% of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt% of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.
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Paragraph 0064-0066
(2017/11/04)
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- Transition-Metal-Free Cross-Coupling of Aryl Halides with Arylstannanes
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Transition-metal-free LiCl-promoted cross-coupling reactions of tetraphenyltin, trichlorophenyl-, dichlorodiphenyl-, and chlorotriphenylstannanes with aryl halides in DMF provided access to biaryls in good to high yields. Up to four phenyl groups were transferred from the organostannanes substrates. The aryls bearing electron-withdrawing groups in either halides or organotin substrates gave coupling products in higher yields. The methodology has been applied for the efficient synthesis of ipriflavones.
- He, Qing,Wang, Liwen,Liang, Yong,Zhang, Zunting,Wnuk, Stanislaw F.
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p. 9422 - 9427
(2016/10/17)
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- A fluorous ethylenediamine promoted direct C-H arylation of unactivated arenes with aryl halides
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A novel and recyclable fluorous ethylenediamine was prepared. Together with potassium tert-butoxide, the fluorous ethylenediamine showed a good activity in promoting the coupling of aryl halides with benzene derivatives without the aid of transition-metal catalysts. Furthermore, a chain homolytic aromatic substitution mechanism was proposed in this paper.
- Zhu, Yi-Wei,Shi, Yi-Xin
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supporting information
p. 10 - 13
(2016/07/06)
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- Reactivity of [K3(phen)8][Cu(NPh2) 2]3 - A possible intermediate in the copper(i)-catalyzed N-arylation of N-phenylaniline
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Complex [K3(phen)8][Cu(NPh2) 2]3 (1, phen = phenanthroline) was isolated from the catalytic C-N cross coupling reaction based on the CuI-phen-tBuOK catalytic system. Complex 1 can react with 4-iodotoluene to give 4-methyl-N,N- diphenylaniline (3a) in 50% yield (based on all available NPh2 - ligands of complex 1). In addition, 1 can also work as an effective catalyst for the C-N coupling reactions under the same reaction conditions, indicating that 1 may be an effective intermediate of the catalytic system. In the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), a radical scavenger, the stoichiometric reaction between complex 1 and 4-iodotoluene was significantly quenched to give a low yield of 12%. The results suggest that the radical path dominates in the reaction, with (phen)KNPh2 as the possible radical source. The structures of 1 and (phen)KNPh2 were both determined by single crystal X-ray diffraction studies.
- Tseng, Chia-Kai,Lee, Chi-Rung,Tseng, Mei-Chun,Han, Chien-Chung,Shyu, Shin-Guang
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p. 7020 - 7027
(2014/05/06)
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- Di-tert-butyl peroxide promoted direct C-H arylation of unactivated arenes with aryl halides
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Di-tert-butyl peroxide can smoothly promote the coupling of aryl halides with benzene derivatives without the aid of transition-metal catalysts through a chain homolytic aromatic substitution mechanism in the presence of potassium tert-butoxide. Radical reasoning: Di-tert-butyl peroxide and potassium tert-butoxide smoothly direct the C-H arylation of unactivated benzene derivatives with aryl halides without the aid of a transition metal. Reactions occur through a base-promoted homolytic aromatic substitution process and involve aryl radicals and aryl radical anions as intermediates. The process to synthesize biaryl compounds is high yielding and practical.
- Zhu, Yi-Wei,Yi, Wen-Bin,Qian, Jin-Long,Cai, Chun
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p. 733 - 735
(2014/03/21)
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- Nickel-catalyzed hydrogenolysis of unactivated carbon-cyano bonds
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Selective hydrogenolysis of C-CN bonds can allow chemists to take advantage of ortho-directing ability, α-C-H acidity and electron withdrawing ability of the cyano group for synthetic manipulations. We have discovered hydrogenolysis of aryl and aliphatic cyanides under just 1 bar of hydrogen by using a nickel catalyst. This protocol was applied in the aryl cyanide directed functionalization reaction and α-substitution of benzyl cyanides.
- Patra, Tuhin,Agasti, Soumitra,Modak, Atanu,Maiti, Debabrata
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supporting information
p. 8362 - 8364
(2013/09/23)
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- C-H arylation of unactivated arenes with aryl halides catalyzed by cobalt porphyrin
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A general procedure for cobalt-catalyzed direct C-H arylation of unactivated arenes has been discovered. This method employs aryl halides as the direct coupling partners with arenes without using any Grignard-type reagents. This catalysis opens a new methodology for the preparation of symmetrical as well as unsymmetrical biaryls in a user-friendly approach.
- To, Ching Tat,Chan, Tek Long,Li, Bao Zhu,Hui, Ying Ying,Kwok, Tsz Yiu,Lam, Suet Yu,Chan, Kin Shing
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supporting information; experimental part
p. 1023 - 1026
(2011/03/20)
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- Synthesis, characterization and catalytic behaviors of neutral nickel complexes: Arylnickel N-alkyl-6-(1-(arylimino)ethyl)picolinamide
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A series of novel neutral nickel complexes, aryl (phenyl or naphthyl) nickel N-alkyl-6-(1-(arylimino)ethyl)picolinamides, were synthesized and characterized by NMR and IR spectroscopy and elemental analysis. Single-crystal X-ray diffraction analyses of the complexes C2, C3 and C7 reveal distorted square-planar geometry along with the molecular structure of one free ligand L1. On activation with diethylaluminum chloride (Et2AlCl), the nickel complexes exhibited moderate catalytic activities for ethylene oligomerization, and the catalytic activity was up to 2.45 × 105 g mol-1(Ni) h-1 in the presence of 1 equiv. PPh3. Moreover, these complexes also exhibit moderate activities for Kumada-Corriu reaction and polymerization of methyl methacrylate.
- Shen, Miao,Hao, Peng,Sun, Wen-Hua
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p. 1683 - 1695
(2008/09/18)
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- Palladium-catalyzed desulfinylative Negishi C-C bond forming cross-couplings of sulfonyl and organozinc chlorides
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Arene-, phenylmethane- and alkenesulfonyl chlorides are suitable electrophilic reagents in desulfinylative carbon-carbon bond formation cross-coupling reactions with organozinc reagents.
- Dubbaka, Srinivas Reddy,Vogel, Pierre
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p. 3345 - 3348
(2007/10/03)
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- A surprisingly mild and versatile method for palladium-catalyzed Suzuki cross-couplings of aryl chlorides in the presence of a triarylphosphine
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In the presence of new air-stable triarylphosphine 2, palladium-catalyzed Suzuki reactions of a wide array of aryl chlorides can be accomplished in uniformly good yield, including couplings of very sterically demanding and electronically deactivated subst
- Liu,Choi,Fu
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p. 2408 - 2409
(2007/10/03)
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- Evolution of products in the combustion of scrap tires in a horizontal, laboratory scale reactor
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A horizontal laboratory reactor was used to study the evolution of byproducts from the combustion of scrap tires at five nominal temperatures (ranging from 650 to 1050 °C) and different oxygen:sample ratios A model was used to calculate the bulk air ratio (λ), and the oxygen consumption was discussed considering this ratio λ. More than 100 volatile and semivolatile compounds were identified and quantified by gas chromatography mass spectrometry, plotting their yields vs the bulk air ratio and temperature. Five different behaviors considering the bulk air ratio and the temperature were identified.
- Fullana,Font,Conesa,Blasco
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p. 2092 - 2099
(2007/10/03)
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- Characterization of the combustion products of polyethylene
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Polyethylene (PE) was burned in a tube-type furnace with an air flow at a temperature of 600~900°C. Combustion products were collected with glass wool, glass fiber filter, and XAD-2 adsorbent. The analysis of the products was performed with GC-FID and GC-MSD. At low temperature, hydrocarbons were the major components, while at higher temperature the products were composed of polycyclic aromatic hydrocarbons. With the high performance of the Hewlett-Packard 6890GC-5973MSD, more compounds were identified in comparison with previous studies.
- Piao, Mingjun,Chu, Shaogang,Zheng, Minghui,Xu, Xiaobai
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p. 1497 - 1512
(2007/10/03)
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- A Re-examination of the Sonochemical Coupling of Bromoaryls.
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The sonochemical coupling of bromotoluenes leads to a mixture of isomeric bitolyls suggesting a radical mechanism, confirmed using radical scavengers which inhibit the reaction.
- Price, Gareth J.,Clifton, Andrew A.
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p. 7133 - 7134
(2007/10/02)
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- Activation of Aromatic Carbon-Hydrogen Bonds by Palladium(II) Acetate-Dialkyl Sulfide Systems. Formation and Characterization of Novel Diphenyltripalladium(II) Complexes
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Palladium(II) acetate reacts wuth benzene in the presence of dialkyl sulfides at 70 deg C to afford novel diphenyltripalladium(II) complexes of 1SR2)PhPd(μ-MeCO2)2Pd(μ-MeCO2)2PdPh(R1SR2)> (1a; R1=But, R2=CH2But; 1b; R1=R2=But: 1c; R1=R2=Pri; 1d; R1=R2=Et) Adducts, tSCH2Bu')2> and i2)2>, prepared by the reactions of palladium(II) acetate and the corresponding dilakyl sulfides in benzene at 5-10 deg C, change to 1a and 1c, respectively, on heating in benzene at 70 deg C.In contrast, reactions of palladium(II) acetate with toluene or thiophene in the presence od diisopropyl sulfide afford no isolable tolyl- or thienyl-palladium species, but coupling products, i.e. bitolyls or bithienyls, are detected by GLC analysis.Treatment of 1b with styrene produces trans-stilbene, whereas 1c reacts with carbon monoxide as well as carbon dioxide to yield benzoic acid.When palladium(II) acetate and t-butyl phenethyl sulfide are heated at 80 deg C in benzene, an adduct tSCH2CH2Ph)2> is formed, in sharp contrast with the case of benzyl t-butyl sulfide, which gives a cyclopalladated complex under the same reaction conditions.
- Fuchita, Yoshio,Hiraki, Katsuma,Kamogawa, Yasuko,Suenaga, Miho,Tohgoh, Kazutaka,Fujiwara, Yuzo
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p. 1081 - 1085
(2007/10/02)
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- Catalytic Formation of Biaryls from Arenes through C-H Bond Activation by RhCl(CO)(PMe3)2 under Irradiation
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Arenes were dehydrogenatively coupled into biaryls catalyzed by RhCl(CO)(PMe3)2 at room temperature under irradiation.The regioselectivity obtained in the reaction of toluene suggested the presence of a radical intermediate.
- Sakakura, Toshiyasu,Sodeyama, Touru,Tokunaga, Yuko,Tanaka, Masato
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p. 2211 - 2214
(2007/10/02)
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- DECOMPOSITION OF (NiRR'L2) COMPLEXES INDUCED BY BROMINE OR ANODIC OXIDATION
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A study has been made of the decomposition of the compounds t-(NiRR'L2) (L=PMe2Ph and PEt3; R=aryl or vinyl groups) and (Ni(mes)(o-tol)bipy) (mes=mesityl) oxidatively induced either by electrochemical means or by bromine.No organometallic compound of Ni(III) was isolated in the above reactions, but a pentacoordinate intermediate of Ni(III) is postulated.Breakdown takes place readily after the Ni(III) intermediate is formed.If the decomposition is induced is induced electrochemically, the intermediate decomposes giving only the coupling product R-R'.When bromine is used as the oxidizing agent, the Ni(III) intermediate is only formed if coordination to the central atom is allowed by the volume of the ligands.Thus, (Ni(C2Cl3)(mes)(PMe2Ph)2) dos not decompose at all, and only (Ni(C2Cl3(mesBr2)(PMe2Ph)2) is obtained.The intermediate ' Ni(III)RR'BrL2' undergoes reductive elimination to give R-R', RBr and R'Br.The formation of the products R-R'is increasingly favoured the greater the electronegativity of the organic ligands.The reductive elimination giving RBr takes place more readily the greater the electronegativity of the organic ligand R.The product of the reductive elimination reaction is 'Ni(I)Br', 'Ni(I)R', or 'Ni(I)R'', which in the presence of bromine give Ni(2+), (NiBr(RBr)L2), phosphonium salts, RBr, and R'Br.
- Coronas, Juan M.,Muller, Guillermo,Rocamora, Mercedes
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p. 227 - 236
(2007/10/02)
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- Phase-Transfer-Catalyzed Gomberg-Bachmann Synthesis of Unsymmetrical Biarenes: A Survey of Catalysts and Substrates
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Two problems have hindered the Gomberg-Bachmann (GB) and Pschorr reactions of arenediazonium cations: the instability of the arenediazonium salts and side reactions.Arenediazonium tetrafluoroborate and hexafluorophosphate salts can be prepared in high yield and purity and can be stored safely.Unfortunately, these salts are insoluble in most nonpolar organic solvents.Crown ether complexation or other phase-transfer (pt) catalytic methodology can ameliorate this situation, and reactions conducted by the approaches outlined herein often afforded coupling or cyclization products in high yield and corresponding purity.The use of crown ethers, quarternary 'onium salts, lipophilic carboxylic acid salts, and even the polar cosolvent acetonitrile increase the utility of the ptGB reaction dramatically.Sixty examples of couplings are reported along with an assessment of selectivities.A number of examples are also presented of phase-transfer-type Pschorr cyclizations.In the latter case, the use of potassium superoxide, KO2, is introduced to suppress indazole formation.
- Beadle, James R.,Korzeniowsky, Stephen H.,Rosenberg, David E.,Garcia-Slanga, Blanche J.,Gokel, George W.
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p. 1594 - 1603
(2007/10/02)
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- PALLADIUM(II)-CATALYZED OXIDATIVE COUPLING OF ARENES BY THALLIUM(III)
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Oxidation of benzenes with electron-donating and moderate electron-withdrawing substituents by thallium(III) trifluoroacetate in the presence of catalytic amounts of palladium(II) acetate affords biaryls in good yields.The GLC study of the isomer distribution has shown that 4,4'-biaryls are the major products.Thus, the 4,4'-biaryls can be easily isolated either by recrystallization or column chromatography.The competitive experiments and kinetic study using arenes and arylthallium derivatives as starting materials as well as quenching experiments have demonstrated the first step of the reaction to be fast thallation of arene to form arylthallium intermediate ArTl(OOCCF3)2.The latter undergoes the rate-determining transmetallation step reacting with monomeric complex Pd(OAc)2, which is formed upon depolymerization of trimer Pd3(OAc)6.Subsequent fast decomposition of arylpalladium species gives the final reaction products.The thallation of arene and substitution of TlIII for PdII in ArTl(OOCCF3)2 are characterized by the slopes of Hammet plots of -5.6 (?+) and -3.0 (?), respectively.
- Yatsimirsky, Anatoly K.,Deiko, Sergei A.,Ryabov, Alexander D.
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p. 2381 - 2392
(2007/10/02)
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