SOLVENT EFFECTS ON THE SOLVOLYSIS OF P-NITROBENZYL AND 3,5-BIS(TRIFLUOROMETHYL)BENZYL P-TOLUENESULFONATES

Solvolysis rates of p-nitrobenzyl and 3,5-bis(trifluoromethyl)benzyl p -toluenesulfonates were determined in a wide variety of solvents. The solvent effects were analyzed based on the Winstein-Grunwald equation. The solvent effect on these deactivated benzyl solvolyses failed to g ive a single linear correlation with the 2-adamantyl Y-OTs parameter. The lower response to the solvent polarity and the pattern of dispersi on for respective binary solvent series can be interpreted in terms of nucleophilic solvent assistance. The application of the equation gave a low m value of 0.4 and a large l of close to unity for both derivat ives. Furthermore, the l value is also comparable to that for ethyl p- toluenesulfonate and even close to that for the methyl derivative, whi ch has generally been defined as the standard S(N)2 substrate.