Solvation effects on alternative nucleophilic substitution reaction paths for chloride/allyl chloride and γ-methylated congeners

An adiabatic connection method, mPW1PW91(0.581)/6-31G(d), was employed in conjunction with the continuum solvation model SM5.42 to study the effects of solvation on the S_N1, S_N2, and syn and anti S_N2′ nucleophilic substitution reactions of chloride anion with allyl chloride and its γ-methylated analogues Z- and E-crotyl chloride and isoprenyl chloride. The impact of equilibrium solvation on the potential energy surfaces of these systems is large and leads to significant changes in both the geometries and the relative energetics of different reaction pathways for different species. The predicted effects of increased solvent dielectric constant are consistent with available experimental data and provide semiquantitative insights into the relative influence of different solvents on particular properties.