611-43-8Relevant academic research and scientific papers
Direct synthesis of dimethylbiphenyls by toluene coupling in the presence of palladium triflate and triflic acid
Xu, Bo-Qing,Sood, Dhiraj,Iretskii,White, Mark G.
, p. 358 - 366 (1999)
A direct coupling reaction of toluene for synthesis of DMBP is reported in the presence of a strong acid, such as trifluoromethane sulfonic acid (TfOH) and Pd(II)triflate (Pd(TfO)2), at room temperature. The presence of both Pd(TfO)2 and TfOH was crucial for an effective coupling of toluene. The reaction rate was promoted by H+ when the anion was labile such as OTf- so that the overall reactivity of the Pd(II)/HOTf system was greater than that reported by others for the Pd(II) system in weaker acids such as acetic or trifluoroacetic acid. Increasing acid strength to favor coupling in the 3- and 4- positions altered the regioselectivity.
OXIDATION OF METHYL-SUBSTITUTED BIPHENYL COMPOUNDS
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Paragraph 0064-0066, (2017/11/04)
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.
Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
supporting information; experimental part, p. 6146 - 6159 (2012/05/07)
A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
Palladium-catalysed synthesis of nonsymmetrically disubstituted-1,1′- biphenyls from o-substituted aryl iodides through aryl coupling and delayed hydrogenolysis
Deledda, Sara,Motti, Elena,Catellani, Marta
, p. 741 - 747 (2007/10/03)
In the presence of Pd(OAc)2 and norbornene as catalysts, two molecules of an ortho-substituted aryl iodide undergo aryl-aryl coupling to a palladium-bonded biphenylyl intermediate, which is hydrogenolyzed by benzyl alcohol to give 2,3′-disubsti
A Re-examination of the Sonochemical Coupling of Bromoaryls.
Price, Gareth J.,Clifton, Andrew A.
, p. 7133 - 7134 (2007/10/02)
The sonochemical coupling of bromotoluenes leads to a mixture of isomeric bitolyls suggesting a radical mechanism, confirmed using radical scavengers which inhibit the reaction.
Activation of Aromatic Carbon-Hydrogen Bonds by Palladium(II) Acetate-Dialkyl Sulfide Systems. Formation and Characterization of Novel Diphenyltripalladium(II) Complexes
Fuchita, Yoshio,Hiraki, Katsuma,Kamogawa, Yasuko,Suenaga, Miho,Tohgoh, Kazutaka,Fujiwara, Yuzo
, p. 1081 - 1085 (2007/10/02)
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.
Catalytic Formation of Biaryls from Arenes through C-H Bond Activation by RhCl(CO)(PMe3)2 under Irradiation
Sakakura, Toshiyasu,Sodeyama, Touru,Tokunaga, Yuko,Tanaka, Masato
, p. 2211 - 2214 (2007/10/02)
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.
Reactivity of Chalcogen Cluster Polycations
Rosan, A. M.
, p. 377 - 378 (2007/10/02)
The chalcogen polycations S8(AsF6)2, S19(HS2O7)2, and Se4(HS2O7)2 are powerful oxidants entering into electron transfer reactions with hydrocarbons, aromatic compounds, and halides.
The Role of Aroyloxyl Radicals in the Formation of Solvent-derived Products in Photodecomposition of Diaroyl Peroxides. The Reactivity of Substituted Cyclohexadienyl Radicals and Intermediacy of ipso Intermediates
Takahara, Shigeru,Urano, Tishiyuki,Kitamura, Akihide,Sakuragi, Hirochika,Kikuchi, Osamu,et al
, p. 688 - 697 (2007/10/02)
Photolyses of bis(2-thiophenecarbonyl)peroxide (TPO) in benzene and toluene afforded, among free-radical products, biphenyl and dimethylbiphenyls, respectively, which were solely derived from the aromatic solvents.The yields of biphenyls depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations for their dimerization.Photolyses of TPO and dibenzoyl peroxide in 1,3,5-trimethylbenzene afforded also a solvent-derived products, 2,3',4,5',6-pentamethyldiphenylmethane.Its formation provides clear evidence for participation of cyclohexadienyl radicals bearing the aroyloxyl group on the methyl-substituted ipso carbon atom.
