Methane Friedel-Crafts reaction

Applied to the synthesis of hydrocarbons the following results have been obtained by this new method. 9 10-Diphenyl-9 10-dihydroanthracene is formed by the condensation of benzene and chloroform, whilst in the ordinary Friedel-Crafts reaction (A., 194, 254 227, 107) triphenyl-methane (Preparation 6) is the main product, traces of chlorarylmethanes and tetraphenylethane (B., 26, 1952) being also formed. The same compound is also obtained from benzal chloride and benzene. Carbon tetrachloride and benzene give 9 9 10 10-tetraphenyl-9 10-dihydroanthracene as do also phenylchloroform and benzene. In the older reaction triphenylchloromethane (p. 432) is the chief product. 

By Friedel-Craft Reaction.—The best method of preparing the compound is by the Friedel-Craft reaction from benzene and benzyl chloride or by the same reaction from benzene and di-chlor methane. 

Synthesis.—This hydrocarbon is by far the most important of those in which two or more benzene rings are linked together by intervening aliphatic carbon groups. Just as methyl chloride and benzene by the Friedel-Craft reaction yield phenyl methane (methyl benzene or toluene) and methylene chloride, di-chlor methane, with benzene yields di-phenyl methane so by the same reaction tri-chlor methane, chloroform, yields with benzene a hydrocarbon which by this synthesis must be tri-phenyl methane. 

Branchadell, V., Oliva, A., Bertran, J. Theoretical study of the acid-catalyzed Friedel-Crafts reaction between methyl fluoride and methane. 

Nucleophilic substitution of chloride ion from a thenyl chloride by a suitable thienyl species (e.g., a thienyllithium) can also lead to a dithienyl-methane, but this approach has been little used. It was successful for the preparation of 2,2 -dithienylmethane itself,70 but in the interaction of 3-bromo-2-chloromethylthiophene and 3-bromo-2-thienyllithium the yield was low (16%)3 and compared unfavorably with that in the Friedel-Crafts reaction.2... 

An aqueous Friedel-Crafts reaction has also been used in polymer synthesis. The acid-catalyzed polymerization of benzylic alcohol and fluoride functionality in monomeric and polymeric fluorenes was investigated in both organic and aqueous reaction media. Polymeric products are consistent with the generation of benzylic cations that participate in electrophilic aromatic substitution reactions. Similar reactions occurred in a water-insoluble Kraft pine lignin by treatment with aqueous acid. A Bisphenol A-type epoxy resin is readily emulsified in aqueous medium with an ethylene oxide adduct to a Friedel-Crafts reaction product of styrene and 4-(4-cumyl)phenol as emulsifier.Electrophilic substitution reaction of indoles with various aldehydes and ketones proceeded smoothly in water using the hexamethylenetetramine-bromine complex to afford the corresponding Z A(indolyl)methanes in excellent yields.InFs-catalyzed electrophilic substitution reactions of indoles with aldehydes and ketones are carried out in water.Enzymatic Friedel-Crafts-type electrophilic substitution reactions have been reported. ... 

Y. L. Yagupolsldi, T. I. Savina, 1.1. Gems, R. K. Orlova, Zh. Obshch. Khim. 1990,26, 2030-2031. New Friedel-Crafts reaction catalyst tris(fluorosulfonyl)methane. 

This synthesis, in common with the production of anthracene based on diphenyl-methane by Friedel-Crafts reaction and dehydrogenation, has had no industrial significance to date. 

Ipatieff and coworkers carried out the first alkylation with alkenes and branched and normal chain alkanes (except methane and ethane) in the presence of AlCb as the catalyst. The sulfuric acid catalyzed alkylation reaction of arenes and isoalkanes, developed in 1938, is a still widely used industrial process to produce alkylates with high octane numbers. For synthetic applications, however, Friedel-Crafts-type alkylations of alkenes and alkanes have limited value since they tend to give mixtures of products, including oligomers of alkenes. ... 

The reaction can be used to make carboxylic acids (from the NaOCOR), and is especially useful when R is an aromatic group because the starting ketone, RCOCH3, can be produced by Friedel-Crafts acetylation. See also triiodo-methane. 

Reductions. In contrast to hydrosilylation reactions catalyzed by metal chlorides, aldehydes and ketones are rapidly reduced at rt by Triethylsilane and BF3-OEt2, primarily to symmetrical ethers and borate esters, respectively. Aryl ketones like acetophenone and benzophenone are converted to ethylbenzene and diphenyl-methane, respectively. Friedel-Crafts acylation-silane reduction reactions can also occur in one step using these reagents thus Benzoyl Chloride reacts with benzene, triethylsilane, and BF3-OEt2 to give diphenyhnethane in 30% yield. ... 

As alluded (vide supra), some confusion may arise with respect to this named reaction as there is reference in the literature to an alternative reaction with the same name. The Bradsher reaction forms aromatic rings but via an acid-catalyzed Friedel-Crafts-like process. Thus diaryl-methanes having a carbonyl group in the ortho position can undergo a cyclodehydration reaction to generate the corresponding anthracene derivatives. In this respect, the Bradsher reaction is related to the Elbs reaction, which involves the pyrolytic cyclization of diaryl ketones 6 having an ortho methyl or methylene substituent for the formation of polycyclic aromatics 7. 

The self-condensation of furan-2-yl alcohols and subsequent intramolecular Friedel-Crafts-type reaction and elimination of an aldehyde catalyzed by ytterbium triflate gave rise to di(furan-2-yl) methanes, which are precursors for the synthesis of biofuels (130BC8030). 

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