Phenonium Ion in Paracyclophanes. Effects of Neighboring Groups, Steric Size of Substituents, and Strain on Solvolysis Reactions

Article abstract of DOI:10.1021/jo00360a034

The effects of steric hindrance, of strain on the structure of the phenonium ion, and of the neighboring group have been studied in the solvolyses of some <3.n>paracyclophanylmethyl tosylates.The reaction path was affected considerably by the steric hindrance of a methyl group attached to the cyclophane skeleton.The effect of strain on the structure of the phenonium ion was clearly demonstrated in the acetolyses of secondary tosylates.A strong anchimeric assistance to the ionization step by the <3.3>paracyclophanyl group was shown.The acetolysis rate constants of <3.n>paracyclophanylmethyl tosylates decreased with increasing methylene chain length.The rate enhancement is attributed to the ?-? transannular interaction of the two overlapping benzene nuclei.