721-45-9Relevant academic research and scientific papers
Development of highly efficient Friedel-Crafts alkylations with alcohols using heterogeneous catalysts under continuous-flow conditions
Kobayashi, Shū,Koumura, Nagatoshi,Masuda, Koichiro,Okamoto, Yukiko,Onozawa, Shun-Ya
, p. 24424 - 24428 (2021/07/29)
The development of Friedel-Crafts alkylations with alcohols under continuous-flow conditions using heterogeneous catalysts is reported. The reactivities and durabilities of the examined catalysts were systematically investigated, which showed that montmorillonite clay is the best catalyst for these reactions. A high turnover frequency of 9.0 × 102h?1was recorded under continuous-flow conditions, and the continuous operation was successfully maintained over one week.
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.
Photochemical benzylic radical arylation promoted by supported Pd nanostructures
Costa, Paolo,Gawargy, Teresa A.,Lanterna, Anabel E.,Scaiano, Juan C.
supporting information, p. 6047 - 6052 (2020/10/21)
We report a novel way to promote photochemical benzylic radical arylations using Pd nanostructures. Traditional benzylic radical reaction pathways are challenged by the presence of metal centres that provoke unprecedented regioselectivity towards more synthetically relevant C(sp3)-C(sp2) couplings. This new C-H activation pathway is rationalised by means of a pseudo-persistent radical effect facilitated by metal centres. We show the mechanistic and computational aspects of the heterogeneous photocatalytic processes that are the root of this drastic change in reactivity. This journal is
Selective Conversion of Benzylic Phosphates into Diarylmethanes Through Al(OTf)3-Catalyzed Friedel–Crafts-Type Benzylation
Yurino, Taiga,Hachiya, Asuka,Suzuki, Keisuke,Ohkuma, Takeshi
, p. 2225 - 2232 (2020/04/16)
Al(OTf)3 was identified as a high-performance catalyst for Friedel–Crafts-type benzylation using benzylic phosphates as electrophiles. The reaction proceeded even with 0.2 mol-% of the catalyst. A series of diarylmethanes (21 examples) was obtained in moderate to high yield. The catalyst showed unique chemoselectivity, preferentially converting the benzylic phosphate motif, even with a benzylic acetate group existed in the same molecule.
Fe-catalyzed double cross-dehydrogenative coupling of 1,3-dicarbonyl compounds and arylmethanes
Yang, Kai,Song, Qiuling
supporting information, p. 548 - 551 (2015/03/05)
Fe-catalyzed tandem cross-dehydrogenative coupling of the methyl group in arylmethanes with 1,3-dicarbonyl compounds has been developed. The reaction affords one new C(sp3)-C(sp2) bond and one new C(sp3)-C(sp3)
Multimetallic Ir-Sn3-catalyzed substitution reaction of π-activated alcohols with carbon and heteroatom nucleophiles
Maity, Arnab Kumar,Chatterjee, Paresh Nath,Roy, Sujit
, p. 942 - 956 (2013/07/25)
An atom economic and catalytic substitution reaction of π-activated alcohols by a multimetallic IreSn3 complex has been demonstrated. The multimetallic IreSn3 complex can be easily synthesized from the reaction between [Cp*IrCl2]2 and SnCl2. In presence of as little as 1 mol % of the catalyst three different types of π-activated alcohols, namely benzyl, allyl, and propargyl alcohols, have been successfully transformed into alkylated products using carbon (arenes, heteroarenes, allyltrimethylsilane, and 1,3-dicarbonyls), nitrogen (sulfonamides), oxygen (alcohols), and sulfur (thiols) nucleophiles in very high yields. An electrophilic mechanism is proposed from the Hammett correlation study.
Iron-catalyzed benzylation reaction of arenes with benzyl thiocyanates
Guo, Xiao-Kang,Zhao, Dong-Yun,Li, Jin-Heng,Zhang, Xing-Guo,Deng, Chen-Liang,Tang, Ri-Yuan
supporting information; experimental part, p. 627 - 631 (2012/03/27)
A novel, regioselective protocol for the synthesis of diphenylmethane derivatives has been developed by using iron-catalyzed Friedel-Crafts reaction of arenes with benzyl thiocyanates. In the presence of FeBr3, a variety of benzyl thiocyanates underwent the reaction with arenes to selectively afford the corresponding diarylmethane derivatives in moderate to high yields. Georg Thieme Verlag Stuttgart · New York.
4-N,N-dimethylaminopyridine promoted selective oxidation of methyl aromatics with molecular oxygen
Zhang, Zhan,Gao, Jin,Wang, Feng,Xu, Jie
body text, p. 3957 - 3968 (2012/07/27)
4-N,N-Dimethylaminopyridine (DMAP) as catalyst in combination with benzyl bromide was developed for the selective oxidation of methyl aromatics. DMAP exhibited higher catalytic activity than other pyridine analogues, such as 4-carboxypyridine, 4-cyanopyridine and pyridine. The sp3 hybrid carbon-hydrogen (C-H) bonds of different methyl aromatics were successfully oxygenated with molecular oxygen. The real catalyst is due to the formation of a pyridine onium salt from the bromide and DMAP. The onium salt was well characterized by NMR and the reaction mechanism was discussed.
InBr3-catalyzed deoxygenation of carboxylic acids with a hydrosilane: Reductive conversion of aliphatic or aromatic carboxylic acids to primary alcohols or diphenylmethanes
Sakai, Norio,Kawana, Keita,Ikeda, Reiko,Nakaike, Yumi,Konakahara, Takeo
experimental part, p. 3178 - 3183 (2011/06/28)
A simple and practical procedure for the direct reduction of aliphatic carboxylic acids with a variety of functional groups to a primary alcohol using the mild reducing reagent tetramethyldisiloxane (TMDS), in the presence of a catalytic amount of InBr3 has been developed. This simple reducing system, when used together with a hydrosilane, allows the preparation of the diphenylmethane derivative directly from an aromatic carboxylic acid and an aromatic compound. Copyright
High catalytic efficiency of nanostructured molybdenum trioxide in the benzylation of arenes and an investigation of the reaction mechanism
Wang, Feng,Ueda, Wataru
experimental part, p. 742 - 753 (2009/10/01)
The synthesis and characterization of nanostructured MoO3 with a thickness of about 30 nm and a width of about 450 nm are reported. The composition formula of the MP (precipitation method) precursor was estimated to be [(NH4)2O]0.169·MoO 3· (H2O)0.239. The calcination of the precursor in air afforded nanostructured pellets of the α-MoO3 phase. The nano-structured MoO3 catalyst exhibited high efficiency in catalyzing the benzylation of various arenes with substituted benzyl alcohols, which were strikingly different to common bulk MoO3. Most reactions offered >99% conversion and >99% selectivity to monoalkylated compounds. MoO3 is a typical acid catalyst. However, the benzylation reaction over nanostructured MoO3 does not belong to the acid-catalyzed type or defect site-catalyzed type, since the catalyst has no acidity and defect site on surface. Characterization with thermal, spectroscopic, and electronic techniques reveal that the catalyst contains fully oxygen-coordinated MoO 6 octahedrons on the surface but partially reduced species (Mo 5+) within the bulk phase. The terminal oxygen atoms of Mo=O bonds on the (010) basal plane resemble oxygen anion radicals and act as active sites for the adsorption and activation of benzyl alcohols by electrophilic attack. Such sites are indispensable for catalytic reactions since the blocking of these sites by electron acceptors, such as tetracyanoethylene (TCNE), can greatly decrease catalytic activity. This work represents a successful example of combining a heterogeneous catalysis study with nanomaterial synthesis.
