SOLVOLYSIS OF 1-(4-METHOXYPHENYL)-L-ARYL-2,2,2-TRIFLUOROETHYL CHLORIDES

The rates of solvolysis of 1-(4-methoxyphenyl)-1-aryl-2,2,2-trifluoeth yl chlorides[I] in a variety of solvents were measured by an electroco nductometric method, LArSR relationships (Yukawa-Tsuno eq.) were found to give a linear plot, log(k/k(0))=-1.84[0 sigma(0)+0.918(sigma(+)-si gma(0))], in 80% aqueous ethanol. Small \rho\ and r values in comparis on with 1-aryll-(trifluoromethyl)ethyl tosylate(p=-6.09, r=1.59) sugge sted that the carbocationic charge in the transition state was dispers ed by a strong p-pi donor, p-methoxy group. Linear mY plots with m=0.9 0 for all of the substituents in aqueous acetone and m=0.60-0.82 for t hose of aqueous ethanol indicate that this solvolysis proceeds via an S(N)1 mechanism with nucleophilic solvent assistance, Thiourea effects and isokinetic temperatures for the tate of solvolysis also can prove the above mechanism.