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1,4-Dibenzylbenzene was successfully synthesized by the Friedel-Crafts benzylation of benzene with 1,4-bis(chloromethyl)benzene using zinc chloride in the presence of polar solvents. In particular, zinc chloride dissolved in primary alcohols or ketones with a molar ratio of 1 was a highly effective catalytic system in the reaction.

Metal-free Friedel–Crafts benzylation (FCB) of scarcely reactive arenes and heteroarenes was performed under on-water conditions by an environmentally sustainable procedure. The catalytic strategy exploits the hydrophobicity of the resorcinarene macrocycle 1 a. The proposed mechanism is based on the activation of benzyl chloride by H-bonding interactions with catalyst 1 a. In fact, under on-water conditions the hydrophobic amplification of the strength of the H-bonding interactions between the OH groups of the resorcinarene catalyst and the chlorine atom of benzyl chloride leads to polarization of the C?Cl bond, which consequently promotes electrophilic attack of the π nucleophile. Thus, many arenes and heteroarenes were efficiently benzylated under mild on-water conditions by using resorcinarene 1 a as catalyst. The FCB of benzene is industrially relevant for the synthesis of diphenylmethane, and hence the on-water procedure was extended to the gram-scale synthesis of diphenylmethane, starting from benzene and benzyl chloride in the presence of resorcinarene catalyst 1 a.

The silica-supported Fe-containing catalysts prepared using FeSO 4 as a precursor exhibit high activity toward the reaction of benzene with benzyl chloride.

An efficient one-pot double Suzuki-Miyaura cross--coupling reaction between bifunctional phenylene-1,4-bis(potassium trifluoroborate) and aryl and heteroaryl bromides is described. The scope and limitations of this methodology that enables the synthesis o

Terephthalic acid reacts with alkyl halides under Birch conditions to substituted 1,4-cyclohexadienes in high yields and good stereoselectivities. Electrophiles containing ester or nitrile groups undergo a surprising fragmentation under the reaction conditions. Subsequent treatment with chlorosulfonic acid proceeds by an interesting tandem decarbonylationldecarboxylation, affording 1,4-dialkylbenzenes in excellent regioselectivity. Thus our new method is superior to classical Friedel-Crafts alkylations.

A novel route to the synthesis of diarylmethanes via a Pd-catalyzed α-arylation of benzyl ketones is rseported. By harnessing the inherent reactivity of enolates, it is possible to circumvent the need for a transmetalating reagent such as boron for the co

Raney Ni-Al alloy in a dilute alkaline aqueous solution has been shown to be a powerful reducing agent, which is highly effective in the reduction of benzophenones to the corresponding hydrocarbon derivatives, in the absence of any organic solvents. Copyright Taylor & Francis Group, LLC.

A highly efficient Suzuki cross-coupling reaction between benzylic halides and aryl boronic acids using palladium chloride as catalyst in acetone:water (3:1) has been developed. High yields of products, mild reaction conditions and short reaction times in the absence of ligand are important features of this method. A highly efficient Suzuki cross-coupling reaction between benzylic halides and aryl boronic acids using palladium chloride as catalyst in acetone:water (3:1) as the solvent system has been developed. High yields of products, mild reaction conditions and short reaction times in the absence of ligand are important features of this method.

The replacement of liquid acid catalyst by solid acids for the Friedel-Crafts reaction of aromatic alkylation is a challenging task. Mixed oxide possessing spinel structures were found to catalyze the Friedel-Craft benzylation of arenes. It was found that the reaction was very fast at 80 °C, hence the reaction was studied with respect to more substrate. The significant point was even at this temperature monobenzylation, with the para isomer predominating, was achieved. Mixed oxides were prepared by co-precipitation method and were characterized by XRD technique.

Friedel-Crafts benzylation and phenethylation reactions of several aromatic compounds with benzyl and phenethyl benzothiazol-2-yl carbonate derivatives were carried out in the presence of scandium triflate (Sc(OTf) 3) as a catalyst. Suitable combinations of the leaving group of carbonates and acid promoters that generate cationic alkyl species were examined.

The cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane-[PdCl(C3H5)]2 system catalyses efficiently the Suzuki cross-coupling reaction of benzylic halides with arylboronic acids. A wide variety of benzylic bromides or chlorides and functionalised arylboronic acids lead selectively to the corresponding diarylmethane adducts in good yields. Furthermore, this catalyst can be used at low loading in many cases.

A mixture of hypophosphorous acid (H3PO2) and iodine in hot acetic acid reduces diaryl ketones quickly and aryl alkyl ketones slowly to the corresponding methylene derivatives. The active reducing agent is hydrogen iodide, generated by reaction between iodine and hypophosphorous acid. (C) 2000 Elsevier Science Ltd.

Nitrogen-separated carbocation-carboxylate ion pairs were employed as sources of carbocations in the alkylation of aromatic compounds. The N-nitrosoamide approach to these nitrogenous-molecule-separated ion pairs is an excellent alternative to the standard acid-catalyzed Friedel-Crafts approach for studies of the alkylation because of the following variables: high reactivity of the electrophile, stability of the products, strict kinetic control, homogeneity, lack of over alkylation, straightforward chemistry, and good product balance. In deaminative benzylations of benzene-toluene and anisole-benzene mixtures, the values of kX/kB and % meta isomer are significantly different from those observed in the standard benzylations in a manner that indicates the deaminative electrophiles are more reactive than those generated by the standard Friedel-Crafts approach. The reactions show a direct proportionality between inter- and intramolecular selectivities and thus follow the Brown selectivity relationship (BSR). The benzylation of 2,4,6-trideuteriotoluene provided no evidence for deuterium rearrangements (or coupled benzyl rearrangements) in the arenium ion intermediate. Kinetic isotope effects were not detected. The methyl substituent on toluene appears to affect intermolecular selectivity (kT/kB) and intramolecular selectivity (o, m, p distribution) to similar degrees. A mechanism is proposed in which both selectivities are determined by activation energy differences in the transition states leading to the σ-complex intermediates. The observation that most standard Friedel-Crafts benzylations do not follow the BSR is discussed in terms of possible systematic errors in those cases. Silver ion-assisted Friedel-Crafts benzylations were performed under dry, basic conditions to investigate whether the standard approach could lead to data that obey the BSR.

Novel mesoporous silicas have been prepared via a sol-gel route involving fluoride-catalyzed hydrolysis of tetraethylorthosilicate (TEOS). Incorporation of zinc chloride by sol-gel synthesis gives a range of mesoporous materials with significantly higher catalytic activity than the commercially available catalyst, Clayzic, in a model Friedel-Crafts alkylation reaction. The dependence of catalytic activity and physical structure on the amounts of solvent, water, zinc chloride, and potassium fluoride used in the preparation are explored, and the materials have been further characterized by nitrogen adsorption to determine surface areas, total pore volumes, and pore-size distributions and by 29Si and 19F MAS NMR spectroscopy. The most active catalysts generally have the highest total pore volumes, with pore-size distributions larger than 8 nm.

In the Friedel Crafts arylmethylation of aromatics with bis(chloromethyl)benzenes using strong Lewis acids (e.g. AlCl3, FeCl3), many side reactions such as transalkylation, dealkylation and polymerization are generally difficult to avoid; however, a similar reaction using silica gel-supported zinc chloride selectively gives a monoarylmethylated compound in high yield.

Aryltrimethylammonium iodides are shown to undergo reaction with Grignard reagents under phosphinate-ligated, low-valent nickel catalysis with the formation of alkylarenes and biaryls.

The chemistry of the alpha , omega -diphenylalkanes, C//6H//5(CH//2)//nC//6H//5 left bracket n equals 1-4 right bracket , in highly purified anhydrous SbCl//3 and SbCl//3-10 mol % AlCl//3 melts has been investigated from 100 to 130 degree C by in situ **1H NMR spectroscopy and by quench and separation techniques. These substrates, which are often used to model the aliphatic chains that link aromatic and hydroaromatic clusters in coal, are found to undergo selective cleavage of the sp**2-sp**3 bond. For n equals 1 and 2 products are formed via a transaralyklation reaction, while for n equals 3 and 4 the cleavage results in the selective production of only benzene and either indan (n equals 3) or tetralin (n equals 4). Toluene is also reactive in SbCl//3-AlCl//3, and typical transalkylation chemistry is observed.