Structure‐reactivity relationship of benzyl benzenesulfonates. Part 3. Prediction of reaction mechanism by the use of correlation interaction coefficients

Abstract

Nucleophilic substitution reactions of (Z)-benzyl (X)-benzene sulfonates with (Y)-pyridines were investigated in acetone at 35°C. The magnitudes of the Hammett reaction constants ρX, ρY and ρZ 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, ρij, can be used to determine the structure of the transition state (TS) for the SN reaction. In particular, the comparison of ρXZ with ρYZ and the sign of ρZ can predict that this reaction series proceed via dissociative SN2 process. This result also accords with the treatment of the MOFJ diagram. The sign of the product ρXZρYZ can predict the movement of the TS.