STRUCTURE-REACTIVITY RELATIONSHIP OF BENZYL BENZENESULFONATES. PART 3. PREDICTION OF REACTION MECHANISM BY THE USE OF CORRELATION INTERACTION COEFFICIENTS

摘要

Nucleophilic substitution reactions of (Z)-benzyl (X)-benzene sulfonates with (Y)-pyridines were investigated in acetone at 35℃. The magnitudes of the Hammett reaction constants ρ_X, ρ_Y and ρ_Z indicate that a stronger nucleophile leads a lesser degree of bond breaking and a better leaving group is accompanied by a lesser degree of bond formation. The magnitude of interaction term, ρ_(ij), can be used to determine the structure of the transition state (TS) for the S_N reaction. In particular, the comparison of ρ_(XZ) with ρ_(YZ) and the sign of ρ_Z can predict that this reaction series proceed via dissociative S_N2 process. This result also accords with the treatment of the MOFJ diagram. The sign of the product ρ_(XZ)ρ_(YZ) can predict the movement of the TS.