Cycloalkanes reaction with arenes

Photoexcited aromatic hydrocarbons undergo hydrogen abstraction and 1,4-addition reactions with cycloalkanes and hydroxylic compounds. These reactions are believed to take place through an excited singlet state of arene to form an exciplex or ion pair as an intermediate, which on back electron transfer dissociates into triplet diradical and undergoes proton abstraction from solvent or amines, followed by addition of an alkyl or aryl unit to give the products [37]. The following examples of this reaction are illustrative ... 

Triton transfer to gaseous toluene and toluene-dg with HeT+ ions was investigated by Cacace and Caromia (1967), whose results, summarized in Table 23, are notably different from those obtained for triton transfer to alkanes and cycloalkanes. The most remarkable discrepancy is represented by the high yield of tritiated toluene, 50 to 60%, in contrast, for instance, with a 9-7% yield of c-CgHuT from triton transfer to cyclohexane. It was suggested that the remarkable stability of proton-ated arene allows a large fraction of the excited ions formed from reaction... 

Difluoroiodo)arenes react with aryl-substituted alkenes to afford the rearranged, geminal difluorides, owing to the migration of the aryl group [32,33]. Likewise, the reaction of substituted cyclic alkenes with difluoroiodotoluene and EtsN/SHF results in a fiuorinative ring-contraction with the selective formation of difluoroalkyl substituted cycloalkanes. Thus, the fluorination of 1-methylcyclohexene derivatives 26 affords... 

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