Abstract: The rates and products of the solvolysis of the exo-and endo-bicyclo [2.1. O] pentane-5-methyl and bicyclo [3.1. O] hexane-6-methyl tosylates in acetic acid and in aqueous ethanol are reported. The data suggest that ionization leads first to the cyclopropylcarbinyl cation. The nature of reactions leading from these ions to the products is discussed. yclopropylcarbinyl and cyclobutyl derivatives are of c considerable interest ...