Phenyl participation in the generation of carbocations from the reactions of some 1-methyl-ω-phenylalkyl toluene-p-sulphonates and ω-phenylalk-1-enes in trifluoroacetic acid

The rates of reaction of four 1-methyl-ω-phenylalkyl toluene-p-sulphonates and four ω-phenylalk-1-enes in buffered trifluoroacetic acid have been measured and the products determined. There is evidence for anchimeric assistance by the phenyl group in both solvolysis and addition reactions when the phenyl group is either β or δ to the incipient carbocation. The nature of such participation is discussed.