A number of phenylalkyl chlorides were synthesized for a comparative study of Friedel–Crafts cyclialkylations and competing reactions involving hydride exchange. The synthetic work showed that phenylbutyl alcohols, especially a tertiary alcohol, may cyclize directly with chlorinating agents to yield tetralins. Cyclialkylation products from phenylpentyl chloride include 1-methyltetralin (4),n-pentylbenzene, 1-methyl-3,4-dihydronaphthalene, and methylnaphthalene. A reaction sequence is given involving dealkylation of4and hydride transfers. Phenylbutyl chloride yielded tetralin,n-butylbenzene, and naphthalene. 1-Chloro-4-methyl-4-phenylpentane yielded 1,1-dimethyltetralin (10), 2-methyl-5-phenylpentane (11), and a small amount of 2-methyl-2-phenylpentane (12). Hydrocarbon11formed from10after cyclialkylation, while12formed by hydride transfer preceding cyclization. Phenylpropyl chloride yielded mainly a hydride transfer product (propylbenzene) and not indane. Treatment of this chloride containing deuterium labels at C-1 and C-2 showed that the hydride ion rearranges from the carbon adjacent to the halogen. 1-Chloro-3-methyl-3-phenylbutane yielded a complex mixture includingt-pentylbenzene, 2-phenyl-3-methylbutane, and products of higher molecular weight.