122-00-9Relevant articles and documents
Formal asymmetric hydration of non-activated alkenes in aqueous medium through a "chemoenzymatic catalytic system"
Schnapperelle, Ingo,Hummel, Werner,Groeger, Harald
, p. 1073 - 1076 (2012)
A direct one-pot conversion of (substituted) styrene(s) into the corresponding (substituted) (R)-phenylethan-1-ol(s) in a highly enantioselective manner has been achieved by using a "chemoenzymatic catalytic system", comprising a palladium-catalyzed Wacker-Tsuji oxidation and subsequent enantioselective enzymatic reduction of the in situ formed (substituted) acetophenone(s) (see scheme). Copyright
Friedel-Crafts acylation of aromatic hydrocarbons using zeolites
Sreekumar,Padmakumar, Raghavakaimal
, p. 777 - 780 (1997)
A convenient heterogeneous catalytic methodology for Friedel-Crafts acylation of benzene and toluene using various aliphatic carboxylic anhydrides over zeolites at 250°C is described. An interesting para selectivity is observed in the case of acylation of toluene over HZSM-5.
Structural effects on the β-scission reaction of alkoxyl radicals. Direct measurement of the absolute rate constants for ring opening of benzocycloalken-1-oxyl radicals
Bietti, Massimo,Lanzalunga, Osvaldo,Salamone, Michela
, p. 1417 - 1422 (2005)
(Chemical Equation Presented) The absolute rate constants for β-scission of a series of benzocycloalken-1-oxyl radicals and of the 2-(4-methylphenyl)-2-butoxyl radical have been measured directly by laser flash photolysis. The benzocycloalken-1-oxyl radicals undergo ring opening with rates which parallel the ring strain of the corresponding cycloalkanes. In the 1-X-indan-1-oxyl radical series, ring opening is observed when X = H, Me, whereas exclusive C-X bond cleavage occurs when X = Et. The factors governing the fragmentation regioselectivity are discussed.
One-pot one-step deracemization of amines using ω-transaminases
Shin, Giyoung,Mathew, Sam,Shon, Minsu,Kim, Byung-Gee,Yun, Hyungdon
, p. 8629 - 8631 (2013)
In this study, we developed a one-pot one-step deracemization method for the production of various enantiomerically pure amines using two opposite enantioselective ω-TAs. Using this method, various aromatic amines were successfully converted to their (R)-forms (>99%) with good conversion.
Copper(I) Catalyzed Differential Peroxidation of Terminal and Internal Alkenes Using TBHP
Mir, Bilal Ahmad,Rajamanickam, Suresh,Begum, Pakiza,Patel, Bhisma K.
, p. 252 - 261 (2020)
Terminal and internal alkenes react contrarily with tert-butyl hydroperoxide (TBHP) giving various products. A Cu(I) catalyzed decarbonylative C–C bond formation followed by a carbonylation–peroxidation of vinyl arenes has been achieved using tert-butyl hydroperoxide (TBHP) as the oxidant in acetonitrile. Whereas, α-methyl styrenes yielded aryl methyl ketones and the α-substituted unsymmetrical internal alkenes afforded selective α-peroxidation under the identical reaction conditions. Concurrent peroxidation–carbonylation–cycloalkylation/cycloetherifiction of internal cyclic alkene such as indene is achieved by switching the solvent system from acetonitrile to cycloalkanes/cyclic ether. All these reactions proceed via radical paths generating interesting peroxo-compounds.
Manganese/Copper Co-catalyzed Electrochemical Wacker-Tsuji-Type Oxidation of Aryl-Substituted Alkenes
Lai, Junshan,Pericàs, Miquel A.
, p. 7338 - 7342 (2020)
A manganese/copper co-catalyzed electrochemical Wacker-Tsuji-type oxidation of aryl-substituted alkenes has been developed. The process involves the use of 5 mol % MnBr2 and 7.5 mol % CuCl2, in 4:1 acetonitrile/water in an undivided cell at 60 °C, with 2.8 V constant applied potential. α-Aryl ketones are formed in moderate to excellent yields, with the advantages of avoidance of palladium as a catalyst and any external chemical oxidant in an easily operated, cost-effective procedure.
Continuous liquid phase acylation of toluene over HBEA zeolite: Solvent effects and origin of the deactivation
Chen, Zhihua,Chen, Wenqi,Tong, Tianxia,Zeng, Aiwu
, p. 231 - 238 (2014)
The continuous liquid phase Friedel-Crafts acylation of toluene (T) by acetic anhydride (AA) over HBEA zeolite was carried out in a fixed bed reactor, with acetic acid (AC) as a solvent. 4-Methylacetophenone (4-MAP) was selectively formed in the initial reaction stage. However, a rapid catalyst deactivation occurred with a sharp decrease of the conversion of acetic anhydride, and this was mainly caused by 4-MAP and heavy compounds ('coke') existing in the zeolite pore, which poisoned the active sites of the catalyst. The use of excess toluene and moderate acetic acid enhanced catalyst activity and stability to some extent as it limited both the retention of 4-MAP and the formation of 'coke'. Moreover, a considerable reduction of Broensted acid sites after deactivation revealed that the toluene acylation is primarily a Broensted acid catalyzed reaction.
Novel palladium nanoparticles supported on mesoporous natural phosphate: Catalytic ability for the preparation of aromatic hydrocarbons from natural terpenes
Mekkaoui, Ayoub Abdelkader,Aberkouks, Abderrazak,Fkhar, Lahcen,Ait Ali, Mustapha,El Firdoussi, Larbi,El Houssame, Soufiane
, (2020)
Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction.
PENTACOORDINATE ORGANOSILICATE AS AN ALKYLATING REAGENT: PALLADIUM CATALYZED METHYLATION OF ARYL HALIDES
Hatanaka, Yasou,Hiyama, Tamejiro
, p. 97 - 98 (1988)
Under the influence of palladium catalyst, tris(diethylamino)sulfonium difluorotrimethylsilicate is found to deliver the methyl group to aryl halides highly chemoselectively, and the corresponding methylated aromatic compounds are produced in moderate to high yields.
Nitrogen-doped carbon nanotubes encapsulate cobalt nanoparticles as efficient catalysts for aerobic and solvent-free selective oxidation of hydrocarbons
Lin, Xiu,Nie, Zhenzhen,Zhang, Liyun,Mei, Shuchuan,Chen, Yuan,Zhang, Bingsen,Zhu, Runliang,Liu, Zhigang
, p. 2164 - 2173 (2017)
The selective oxidation of hydrocarbons to the corresponding ketones with solvent-free and molecular oxygen as an oxidant is of great importance in academic and industrial fields in view of economy and environment. In this respect, we present the facile synthesis and characterization of excellent catalysts comprising cobalt nanoparticles encapsulated into graphitic nitrogen-doped carbon nanotubes (Co@GCNs) via one-pot pyrolysis of a chelate compound containing citric acid, melamine, and CoCl2·6H2O. The selective oxidation of ethylbenzene under molecular oxygen and solvent-free conditions is employed as a probe reaction to investigate the catalytic performance; the optimized catalyst shows the best conversion (68%) and selectivity for acetophenone (93%). Combination of the catalytic results of the control group and the different characterization methods demonstrates that high catalytic activity is due to the synergistic effect between metallic cobalt and nitrogen-doped carbon nanotubes. Moreover, the catalyst has high catalytic activity for the aerobic and solvent-free oxidation of other arylalkane substrates. The proposed mechanistic study illustrates that the reaction is a free radical reaction progressing through superoxide radical anions (?O2-).
