- Efficient metal-catalyzed hydroarylation of styrenes
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A highly efficient metal-catalyzed hydroarylation of various styrenes has been developed. This new bismuth-catalyzed C-H functionalization provides straightforward access to a series of valuable 1,1-diarylalkane products.
- Rueping, Magnus,Nachtsheim, Boris J.,Scheidt, Thomas
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- Nucleophilicity of Alkyl Zirconocene and Titanocene Precatalysts, and Kinetics of Activation by Carbenium Ions and by B(C6F5)3
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Kinetics of activation of methyl and benzyl metallocene precatalysts by benzhydrylium ions, tritylium ions, and triarylborane B(C6F5)3were measured spectrophotometrically. The rate constants correlate linearly with the electrophilicity parameter E of the benzhydrylium and tritylium ions employed, allowing us to determine the σ-nucleophilicities of the metal–carbon bond of several zirconocenes and titanocenes. Bridging, substitution, metal, and ligand effects on the rates of metal–alkyl bond cleavage (M=Zr, Ti) were studied and structure–reactivity correlations were used to predict the kinetics of generation of metallocenium ions pairs, which are active catalysts in polymerization reactions and are highly electrophilic Lewis acids in frustrated Lewis pair catalysis.
- Berionni, Guillaume,Kurouchi, Hiroaki,Eisenburger, Lucien,Mayr, Herbert
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supporting information
p. 11196 - 11200
(2016/08/03)
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- Room Temperature Catalyst System for the Hydroarylation of Olefins
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A simple protocol for the hydroarylation of olefins to yield diarylmethine products is described. A Friedel-Crafts-type synthetic strategy allows direct access to biorelevant products in high atom efficiency. A combination of substoichiometric amounts of TMSCl and ZnBr2 promotes a rapid hydroarylation process at ambient temperature. The method is high yielding and is amenable to scale-up protocols.
- Lee, Siu Yin,Villani-Gale, Alexander,Eichman, Chad C.
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supporting information
p. 5034 - 5037
(2016/10/14)
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- Flying-seed-like liquid crystals 3: New guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains
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In our previous work, we synthesized a series of phthalocyanine-based flying-seed-like compounds, (nPh-PhO)4PcCu (n = 3, 2, 1 and 0 in nPh-PhO: a-d), and revealed that each of them shows a columnar liquid crystalline phase (Colho or Colrho) from rt to an extremely high temperature near 500 °C. Thus, we could obtain columnar liquid crystalline phases for discotic compounds by using bulky substituents (a-d) instead of long alkyl chains. In order to further study the utility of these bulky substituents (a-d) on the induction of mesomorphism for other shaped molecules, we have synthesized novel flying-seed-like calamitic phenoxybenzoic acid derivatives, nPh-PhOBA (3a-d), and their Mitsubishi-Mark-shaped terbium complexes, (nPh-PhOBA)3Tb·mMeOH (4a-d), in this work. Very interestingly, the mesomorphism of the phenoxybenzoic aids derivatives nPh-PhOBA (n = 0-3) was induced to show a mesophase (Mx) only by the bulky substituent d (n = 0), whereas the mesomorphism of their corresponding terbium complexes (nPh-PhOBA)3Tb(III) (n = 0-3) was induced to show rectangular columnar (Colr) mesophases by the bulky substituents c and d (n = 1, 0). On the other hand, the mesomorphism of the PcCu complexes (nPh-PhOBA)4PcCu (n = 0-3) in our previous work was induced by all the bulky substituents a, b, c and d (n = 0-3). Thus, it becomes apparent that both calamitic and columnar mesomorphism can be induced by the substitution of bulky groups instead of long alkyl chains, and that the balance of the core size and the bulkiness of the substituents is very important to obtain mesomorphism in flying-seed-like compounds. We believe that this is a new guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains.
- Hachisuga, Ayaha,Yoshioka, Miho,Ohta, Kazuchika,Itaya, Tomoyuki
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p. 5315 - 5321
(2013/09/23)
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- Versatile friedel-crafts-type alkylation of benzene derivatives using a molybdenum complex/ortho-chloranil catalytic system
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A variety of molybdenum complexes catalyze Friedel-Crafts-type alkylation reactions of benzene derivatives with alkenes and alcohols in the presence of an organic oxidant, o-chloranil. The utilization of [Mo(CO)6] and two equivalents of o-chloranil catalytically furnished the hydroarylation product of norbornene with p-xylene at 80°C, whereas [Cr(CO)6] and [W(CO)6] failed to catalyze the same reaction, thus indicating the importance of the molybdenum source. The best results were obtained when a molybdenum(II) complex [CpMoCl(CO)3] (Cp = cyclopentadienyl) was used as a precatalyst. The hydroarylation reactions also took place with styrenes, cyclohexenes, and 1 -hexene as olefin substrates. The electrophilic-substitution mechanism was proposed on the basis of the ortho/para selectivities and the Markovnikov selectivities observed for the hydroarylation products. Our hypothesis was further corroborated by the fact that in the presence of the [CpMoCl(CO)3]/o-chloranil catalytic system, secondary, benzylic, or allylic alcohols participated in the alkylation of benzenes with similar selectivities.
- Yamamoto, Yoshihiko,Itonaga, Kouhei
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experimental part
p. 10705 - 10715
(2009/12/01)
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- A novel InCl3/SiO2-catalyzed hydroarylation of arenes with styrenes under solvent-free conditions
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A novel InCl3/SiO2-catalyzed hydroarylation of various styrenes with arenes has been developed. The reaction can be carried out under solvent-free conditions to afford a series of 1,1-diarylalkanes in high yields and with good regioselectivities. The catalyst can be reused six times without obvious loss of catalytic activity. Georg Thieme Verlag Stuttgart.
- Sun, Gaojun,Sun, Huayin,Wang, Zhiyong,Zhou, Ming-Ming
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experimental part
p. 1096 - 1100
(2009/04/04)
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- Highly efficient iodine-catalyzed hydroarylation of arenes with styrenes
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Iodine mediates the hydroarylation of styrenes with arenes and heteroarenes to afford 1,1-diarylalkanes in good to high yields. Details regarding the substrate scope and selectivity of this hydroarylation reaction are discussed.
- Chu, Cheng-Ming,Huang, Wan-Ju,Liu, Ju-Tsung,Yao, Ching-Fa
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p. 6881 - 6885
(2008/02/12)
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- An efficient and selective hydroarylation of styrenes with electron-rich arenes, catalyzed by bismuth(III) chloride and affording Markovnikov adducts
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In the presence of BiCl3, the hydroarylation of styrenes with electron-rich arenes afforded Markovnikov adducts selectively in good to high yields. Under arene-free conditions, the intermolecular hydroarylation of α-substituted styrenes and subsequent intramolecular hydroarylation produced the cyclic dimers of α-substituted styrenes in good yields. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Sun, Hong-Bin,Li, Biao,Hua, Ruimao,Yin, Gwu
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p. 4231 - 4236
(2007/10/03)
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