Of arylalkanes

Aromatics react with olefins very readily when potassium is used as a catalyst. However, potassium is less selective in catalyzing alkylation than sodium because an additional reaction yields indans, as reported by Schaap and Pines 24). Therefore, the products consist of mixtures of arylalkanes and indans the relative amount of each depends largely on the aromatic used (as shown in Table II). The degree of alkyl substitution of the o -carbon... 

A possible mechanism of oxidation of methylene groups to carbonyl groups involves autoxidation (oxidation by molecular oxygen) at the benzylic position. Autoxidation of arylalkanes is a facile reaction with low activation energies for example, 6.0 kcal/mole for 1,1-diphenylethane and 13.3 kcal/mole for toluene. ... 

Free-radical side-chain chlorination of arylalkanes in the benzylic position can be effected by chlorine or S02C12. Phosphorus pentachloride is also capable of effectively catalyzing side-chain chlorination. 

Side-Chain Chlorination of Arylalkanes. Alkyl-substituted aromatic compounds can easily be halogenated at the benzylic position with chlorine or bromine.107 108,142 143 a-Monohaloalkylaromatics are usually the main products with both reagents. 

Olah151 and later Messina152 found that PCI5 is a highly effective catalyst for the free-radical side-chain chlorination of arylalkanes. Chlorination in hydrocarbon or chlorinated solvents or without solvent at room temperature yields a monochlo-rinated products with high selectivity. When the reaction was carried out in polar solvents such as nitromethane and nitrobenzene, only ring chlorination occurred. 

Aryl ketones or aldehydes.1 Reaction of arylalkanes with DDQ in aqueous acetic acid can result in carbonyl products. Thus reaction of 1 with DDQ in HOAc-H20 results in the ketone 2, believed to be formed by acetylation at the benzylic position followed by acid-catalyzed hydrolysis to the corresponding alcohol, which is oxidized to a ketone by DDQ. 

Abdel Aziz, H., Nahrstedt, A., Petereit, F., Windeck, T., Ploch, M. and Verspohl, E.J. (2005) 5-HT3 receptor blocking activity of arylalkanes isolated from the rhizome of Zingiber officinale. Planta Medica 71(7), 609-616. 

Bassler (1984) reexamined Pfister s (1977) data for TPA doped PC. Bassler suggested that the field and temperature dependencies of the mobility could be explained by arguments based on energetic disorder. Bassler extended the same argument to a series of arylalkane derivatives doped into a PC and PS (Pai et al., 1983), and charge-transfer complexes formed between 2,4,7-trinitro-9-fluorenone and poly(N-vinylcarbazole) (Gill, 1972,1976). 

The formation of arylalkanes, alkenes and alkynes as well of more functionalized derivatives and some bi(hetero)aryls is exemplified in some schemes below, in order to illustrate the contribution of this reaction to green synthesis (Scheme ISa-c). ... 

Oxidations of arylalkanes by "Bu4NMn04 in toluene solvent led to the conclusion that rate-limiting hydrogen atom transfer from the substrate to a permanganate oxo group is consistent with all of the experimental evidence [69a] ... 

Synthesis.— Thioketones (or enethiols) react with sulphur and carbon disulphide in DMF in the presence of triethylamine to give both 1,2-dithiole-3-thiones and l,3-dithiole-2-thiones thus heptane-4-thione yields 4-ethyl-5-propyl-l,2-dithiole-3-thione (1) and 4-ethyl-5-propyl-l,3-dithiole-2-thione (2). 5-Phenyl-4-styryl-l,2-dithiole-3-thione has been prepared by application of the well-known keten mercaptal synthesis, and some aryl-1,2-dithiole-3-thiones have been obtained, conventionally, by hi -temperature reactions of arylalkanes with sulphur. ... 

Pb(C2H5)4 is employed as a chain-starter for the alkylation of alkanes or cycloalkanes by alkenes or cycloalkenes [697], and in the liquid-phase oxidation of alkylaromatic hydrocarbons to give hydroperoxides [892]. Pb(C2Hs)4 catalyzes the photochemical addition of HBr [661, 681] or of H2S or mercaptans to alkenes, such as propene [661, 679, 681], and it catalyzes the intermolecular condensation of arylalkanes in sunlight or on heating [684]. 

Akaba, R., Kamata, M., Itoh, H., Nakao, A., Goto, S., Saito, K., Negishi, A., Sakuragi, H., and Tolumaru, K., Photoinduced electron-transfer oxygenation of arylalkanes. Generation and oxygenation pathways of benzylic-type free radicals from the cation radical deprotonation. Tetrahedron Lett., 33, 7011, 1992. 

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