Phenomenon of isoparametricity in reactions of trans-2,3-diaryloxiranes with arenesulfonic acids. Mechanistic interpretation

Abstract

Nonadditive effects of substituents X and Y are manifested in reactions of symmetrically X-substituted trans-2,3-diaryloxiranes with Y-substituted arenesulfonic acids. The isoparametric point is reached experimentally: close to the point τ_X^IP = 4.73 on substituent Х the rate of the oxirane ring opening of trans-2,3-bis(3-bromo-5-nitrophenyl)oxirane (τ_X = 4.38) practically does not depend on substituent Y (ρ_Y^X = 0.10±0.05). The results of cross correlation analysis of the kinetic data are applied to interpretation of the mechanism of the studied reactions.