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

Article abstract of DOI:10.1002/(SICI)1099-1395(199610)9:10<701::AID-POC832>3.0.CO;2-Q

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 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_lj 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_XZρ_YZ can predict the movement of the TS.