6031-02-3Relevant academic research and scientific papers
A New Preparation Method for the Alkylation Catalysts of Aromatic Compounds Based on Immobilized AlCl3
Bykov,Belyaev
, p. 328 - 330 (2021/04/26)
Abstract: A new method for the preparation of active catalysts for the alkylation and transalkylation of aromatic compounds (benzene and toluene) based on aluminum chloride immobilized on the surface of silica gel was developed. The alkylation occurred wi
Isobutane/2-butene alkylation catalyzed by Br?nsted-Lewis acidic ionic liquids
Liu, Shiwei,Tan, Shuang,Bian, Bing,Yu, Hailong,Wu, Qiong,Liu, Zhiguo,Yu, Fengli,Li, Lu,Yu, Shitao,Song, Xiuyan,Song, Zhanqian
, p. 19551 - 19559 (2018/06/11)
The alkylation reaction of isobutane with 2-butene to yield C8-alkylates was performed using Br?nsted-Lewis acidic ionic liquids (ILs) comprising various metal chlorides (ZnCl2, FeCl2, FeCl3, CuCl2, CuCl, and AlCl3) on the anion. IL 1-(3-sulfonic acid)-propyl-3-methylimidazolium chlorozincinate [HO3S-(CH2)3-mim]Cl-ZnCl2 (x=0.67) exhibited outstanding catalytic performance, which is attributed to the appropriate acidity, the synergistic effect originating from its double acidic sites and the promoting effect of water on the formation and transfer of protons. The Lewis acidic strength of IL played an important role in improving IL catalytic performance. A 100% conversion of 2-butene with 85.8% selectivity for C8-alkylate was obtained under mild reaction conditions. The IL reusability was good because its alkyl sulfonic acid group being tethered covalently, its anion [Zn2Cl5]- inertia to the active hydrogen, and its insolubility in the product. IL [HO3S-(CH2)3-mim]Cl-ZnCl2 had potential applicability in the benzene alkylation reaction with olefins and halohydrocarbons.
New Heterogeneous Alkylation Catalysts Based on Niobium Pentachloride
Bykov,Belyaev,Butenko
, p. 688 - 689 (2018/10/02)
New active catalysts based on niobium pentachloride immobilized on the surface of silica gel or aluminum oxide for the alkylation of aromatic compounds were prepared. The reaction occurs with a high rate at room temperature. Thus, the conversion of 1-hexene in the alkylation of benzene or toluene was close to 100% only 5 min after the onset of the reaction.
Heterogeneous Catalytic Hydroarylation of Olefins at a Nanoscopic Aluminum Chlorofluoride
Calvo, Beatriz,Wuttke, Jan,Braun, Thomas,Kemnitz, Erhard
, p. 1945 - 1950 (2016/07/06)
We report on hydroarylation reactions of arenes with olefins under very mild conditions catalyzed heterogeneously by aluminum chlorofluoride (ACF; AlClxF3?x, x≈0.05–0.25). The reactions of benzene and toluene with ethylene or propylene proceed with high conversions to afford various alkylated arenes. For cyclohexene and 1-hexene, the reactions require higher temperatures and the conversions are lower. ACF also catalyzes the hydroarylation of 1,3,5-trifluorobenzene and pentafluorobenzene with ethylene and propylene. The alkylations of arenes with non-fluorinated olefins resemble typical Friedel–Crafts chemistry to give rise to Markovnikov regioselectivity. The reaction of CF3CH=CH2 with benzene proceeds with anti-Markovnikov regioselectivity to give the fluorinated olefin PhCHCH=CF2 and the alkylation product PhCH2CH2CF3 as products of C?F and C?H activation.
Cobalt-Catalyzed Asymmetric Hydrogenation of 1,1-Diarylethenes
Chen, Jianhui,Chen, Chenhui,Ji, Chonglei,Lu, Zhan
supporting information, p. 1594 - 1597 (2016/05/02)
Highly enantioselective cobalt-catalyzed hydrogenation of 1,1-diarylethenes was developed by using bench-stable chiral oxazoline iminopyridine-cobalt complexes as precatalysts. A unique o-chloride effect was observed to achieve high enantioselectivity. Easy removal as well as further transformations of the chloro group make this protocol a potentially useful alternative to synthesize various chiral 1,1-diarylethanes. This process can be successfully performed under 1 atm of hydrogen at room temperature on gram scale.
Domino Methylenation/Hydrogenation of Aldehydes and Ketones by Combining Matsubara's Reagent and Wilkinson's Catalyst
Maazaoui, Radhouan,Pin-Nó, María,Gervais, Kevin,Abderrahim, Raoudha,Ferreira, Franck,Perez-Luna, Alejandro,Chemla, Fabrice,Jackowski, Olivier
supporting information, p. 5732 - 5737 (2016/12/14)
The methylenation/hydrogenation cascade reaction of aldehydes or ketones through a domino process involving two ensuing steps in a single pot is realized. The compatibility of Matsubara's reagent and Wilkinson's complex give a combination that allows, under dihydrogen, the transformation of a carbonyl function into a methyl group. This new method is suitable to introduce an ethyl motif from aromatic and aliphatic aldehydes with total chemoselectivity and total retention of α-stereochemical purity. The developed procedure is also extended to the introduction of methyl groups from ketones.
Use of Trifluoromethyl Groups for Catalytic Benzylation and Alkylation with Subsequent Hydrodefluorination
Zhu, Jiangtao,Prez, Manuel,Caputo, Christopher B.,Stephan, Douglas W.
supporting information, p. 1417 - 1421 (2016/02/14)
The electrophilic organofluorophosphonium catalyst [(C6F5)3PF][B(C6F5)4] is shown to effect benzylation or alkylation by aryl and alkyl CF3 groups with subsequent hydrodefluorination, thus resulting in a net transformation of CF3 into CH2-aryl fragments. In the case of alkyl CF3 groups, Friedel-Crafts alkylation by the difluorocarbocation proceeded without cation rearrangement, in contrast to the corresponding reactions of alkyl monofluorides.
Extending the substrate scope of bicyclic p-oxazoline/thiazole ligands for ir-catalyzed hydrogenation of unfunctionalized olefins by introducing a biaryl phosphoroamidite group
Biosca, Maria,Paptchikhine, Alexander,P??mies, Oscar,Andersson, Pher G.,Di??guez, Montserrat
supporting information, p. 3455 - 3464 (2015/03/04)
This study identifies a series of Ir-bicyclic phosphoroamidite-oxazoline/thiazole catalytic systems that can hydrogenate a wide range of minimally functionalized olefins (including E- and Z-tri- and disubstituted substrates, vinylsilanes, enol phosphinates, tri- and disubstituted alkenylboronic esters, and ?±,?2-unsaturated enones) in high enantioselectivities (ee values up to 99%) and conversions. The design of the new phosphoroamidite-oxazoline/thiazole ligands derives from a previous successful generation of bicyclic N-phosphane-oxazoline/thiazole ligands, by replacing the N-phosphane group with a p-acceptor biaryl phosphoroamidite moiety. A small but structurally important family of Ir-phosphoroamidite-oxazoline/thiazole precatalysts has thus been synthesized by changing the nature of the Ndonor group (either oxazoline or thiazole) and the configuration at the biaryl phosphoroamidite moiety. The substitution of the N-phosphane by a phosphoroamidite group in the bicyclic N-phosphane-oxazoline/thiazole ligands extended the range of olefins that can be successfully hydrogenated.
A modular furanoside thioether-phosphite/phosphinite/ phosphine ligand library for asymmetric iridium-catalyzed hydrogenation of minimally functionalized olefins: Scope and limitations
Coll, Mercedes,Pamies, Oscar,Dieguez, Montserrat
, p. 143 - 160 (2013/03/28)
A highly modular furanoside thioether-phosphite/phosphinite/phosphine ligand library has been synthesized for the iridium-catalyzed asymmetric hydrogenation of minimally functionalized olefins. These ligands can be prepared efficiently from easily accessible D-(+)-xylose. We found that their effectiveness at transferring the chiral information in the product can be tuned by correctly choosing the ligand components. Enantioselectivities were therefore excellent (ees up to 99%) in a wide range of E- and Z-trisubstituted alkenes using 5-deoxyribofuranoside thioether-phosphite ligands. It should be pointed out that these catalysts are also very tolerant to the presence of a neighbouring polar group. For 1,1-disubstituted substrates, both enantiomers of the hydrogenation product can be obtained in high enantioselectivities simply by changing the configuration of the biaryl phosphite moiety. The asymmetric hydrogenation was also performed using propylene carbonate as solvent, which allowed the iridium catalysts to be reused while maintaining the excellent enantioselectivities. Copyright
A phosphite-pyridine/iridium complex library as highly selective catalysts for the hydrogenation of minimally functionalized olefins
Mazuela, Javier,Pamies, Oscar,Dieguez, Montserrat
supporting information, p. 2569 - 2583 (2013/10/21)
A modular library of readily available phosphite-pyridine ligands has been successfully applied for the first time in the iridium-catalyzed asymmetric hydrogenation of a broad range of minimally functionalized olefins. The modular ligand design has been shown to be crucial in finding highly selective catalytic systems for each substrate. Excellent enantioselectivities (ees up to 99%) have therefore been obtained in a wide range of E- and Z-trisubstituted alkenes, including more demanding triaryl-substituted olefins and dihydronaphthalenes. This good performance extends to the very challenging class of terminal disubstituted olefins, and to olefins containing neighbouring polar groups (ees up to 99%). Both enantiomers of the reduction product can be obtained in excellent enantioselectivities by simply changing the configuration of the carbon next to the phosphite moiety. The hydrogenations were also performed using propylene carbonate as solvent, which allowed the iridium catalyst to be reused and maintained the excellent Copyright
