6165-51-1Relevant academic research and scientific papers
Multifunctional oxygen vacancies in WO3–x for catalytic alkylation of C–H by alcohols under red-light
Gu, Xianmo,Sun, Xichen,Wang, Yunwei,Zhang, Jin,Zheng, Zhanfeng,Zhu, Pengqi
, p. 208 - 217 (2021/09/06)
Surface reaction kinetics and light absorption properties of a photocatalyst are essential demands for efficiently solar to chemical energy converting. In this study, plasmonic WO3–x was firstly applied to photocatalytic alkylation of arenes under red light irradiation. The oxygen vacancies, both on the surface and in the bulk of WO3–x, allow abundant free electrons to increase carrier densities and support its LSPR using low energy photons. The surface oxygen vacancies have more functions: they not only release surface tungsten sites which ensure the chemisorption of alcohols due to the coordianation ability but also promote the activation of alcohols via an efficient transport of the holes on the neighbouring O sites to chemisorption alcohol species. In brief, the bulk oxygen vacancies provide abundant charges and the surface vacancies promote the bond adsorption and activation abilities, which ensure the high efficiency of photocatalytic alkylation of C–H.
Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
supporting information, p. 6007 - 6014 (2019/06/24)
A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
Bisulfate Salt-Catalyzed Friedel-Crafts Benzylation of Arenes with Benzylic Alcohols
Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
, p. 14001 - 14009 (2018/11/23)
We report here a method of direct Friedel-Crafts benzylation of arenes with benzylic alcohols using cheap and readily available bisulfate salt as the catalyst in hexafluoroisopropanol. The catalytic system is powerful with a quite diverse group of functionalized arenes and benzylic alcohols. These mild conditions provide a straightforward synthesis of a variety of unsymmetrical diarylmethanes in high yield with good to high regioselectivity. An SN1 mechanism involving activation of the hydroxy group through a hydrogen bond is proposed.
Reductive cross-coupling of conjugated arylalkenes and aryl bromides with hydrosilanes by cooperative palladium/copper catalysis
Semba, Kazuhiko,Ariyama, Kenta,Zheng, Hong,Kameyama, Ryohei,Sakaki, Shigeyoshi,Nakao, Yoshiaki
supporting information, p. 6275 - 6279 (2016/05/24)
A method for the reductive cross-coupling of conjugated arylalkenes and aryl bromides with hydrosilanes by cooperative palladium/copper catalysis was developed, thus resulting in the highly regioselective formation of various 1,1-diarylalkanes, including a biologically active molecule. Under the applied reaction conditions, high levels of functional-group tolerance were observed, and the reductive cross-coupling of internal alkynes with aryl bromides afforded trisubstituted alkenes. Forming a Co-op: A method for the reductive cross-coupling of conjugated arylalkenes or internal alkynes and aryl bromides with hydrosilanes using cooperative palladium/copper catalysis was developed. The resulting 1,1-diarylalkanes and trisubstituted alkenes were isolated with high regio- and stereoselectivity. Under the applied reaction conditions, high levels of functional-group tolerance were observed.
Hydroarylation of styrenes with electron-rich arenes over acidic ion-exchange resins
Wen, Jingyun,Qi, Haofei,Kong, Xiangjin,Chen, Ligong,Yan, Xilong
, p. 1893 - 1903 (2014/07/07)
A series of acidic cation-exchange resins were used for the hydroarylation of resorcinol with styrene, in which resin D072 exhibited the excellent catalytic performance in this reaction with 99% conversion of styrene and 90% selectivity of 4-(1-phenylethyl)resorcinol. It was applied to the hydroarylation of various electron-rich arenes with styrenes, and the hydroarylated products were quantitatively obtained. This catalyst could be used for four consecutive runs with slight decrease in activity. The hydroarylation of resorcinol with styrene over resin D072 in a fixed bed was completed effectively with 94% selectivity and 99% conversion, and this green continuous process is potentially applicable to large-scale productions.
Iron-catalyzed arylation of aromatic ketones and aldehydes mediated by organosilanes
Savela, Risto,Majewski, Marcin,Leino, Reko
, p. 4137 - 4147 (2014/07/08)
A simple and efficient iron-catalyzed method for arylation of aromatic carbonyl compounds is reported. The use of 4-% FeCl3 or Fe(acac) 3 as the catalyst, in combination with a slight excess of chlorotrimethylsilane and triethylsilane, chlorination of benzylic ketones and aldehydes with subsequent Friedel-Crafts alkylation of arenes is achieved. Although the method is limited by the general constraints associated with Friedel-Crafts alkylation reactions, robust applications for the synthesis of pharmaceutical intermediates and so on can be envisioned. A robust one-pot, iron-catalyzed chlorination Friedel-Crafts alkylation reaction of benzylic carbonyl compounds, mediated by chlorotrimethylsilane and triethylsilane, has been developed to yield substituted diaryl and triaryl building blocks. Copyright
Synthesis of diarylmethanes via a Friedel-Crafts benzylation using arenes and benzyl alcohols in the presence of triphenylphosphine ditriflate
Khodaei, Mohammad Mehdi,Nazari, Ehsan
experimental part, p. 5131 - 5135 (2012/09/22)
Triphenylphosphine ditriflate (TPPD) was found to be an efficient promoter for the Friedel-Crafts benzylation of arenes with benzyl alcohols in CH 2Cl2 at room temperature. The good yields, the 1:1 molar ratio of arene and benzyl alcohol, the benzylation of chlorobenzene as a nonactivated aromatic compound at room temperature, and no by-product formation are the main advantages of this procedure.
Iron(iii)-based ionic liquid-catalyzed regioselective benzylation of arenes and heteroarenes
Gao, Jian,Wang, Jin-Quan,Song, Qing-Wen,He, Liang-Nian
, p. 1182 - 1186 (2011/06/25)
An easily prepared Fe(iii)-derived Lewis acid ionic liquid ([C 4mim][FeCl4]), being comprised of 1-butyl-3-methyl imidazolium cation and tetrachloroferrate anion, was found to be an efficient, recyclable catalyst for benzylation of various arenes/heteroarenes into the diarylmethanes derivatives under mild reaction conditions without utilization of additional organic solvent. Interestingly, the acidity of [C 4mim][FeCl4] could account for its catalytic activity in promoting the Lewis acid-catalyzed alkylation. Notably, this type of Fe(iii)-based ionic liquid (IL) shows excellent stability, and could be easily recovered, and reused for five times without significant loss of its catalytic activity.
Zinc chloride enhanced arylations of secondary benzyl trifluoroacetates in the presence of b-hydrogen atoms
Duan, Hui,Meng, Lingkui,Bao, Denghui,Zhang, Heng,Li, Yao,Lei, Aiwen
supporting information; experimental part, p. 6387 - 6390 (2010/11/04)
Zinc or swim: Arylation of benzyl trifluoroacetates with arylzinc reagents in the presence of β- hydrogen atoms were realized under mild conditions. Both electron-rich and electron-deficient arene substrates were successfully arylated. This arylation method could offer a very versatile synthetic route to access a series of diversity-oriented diarylalkane motifs. TFA = trifluoroacetyl. Copyright
Iron oxide nanoparticles grown on carboxy-functionalized graphite: An efficient reusable catalyst for alkylation of arenes
Rajpara, Vikul,Banerjee, Subhash,Sereda, Grigoriy
experimental part, p. 2835 - 2840 (2010/10/04)
Here we report a simple procedure for the synthesis of a novel hybrid catalyst by growing iron oxide nanoparticles on carboxy-functionalized graphite. This hybrid catalyst demonstrated superior catalytic activity towards the alkylation of arenes with alkyl halides in contrast to commercial graphite or unsupported iron oxide nanoparticles in terms of yields and general applicability. The catalyst can be reused up to five times with a minimal loss of catalytic activity. Georg Thieme Verlag Stuttgart.
