A Comparative LSER Study of the Reactivity of 2-Substituted Cyclohex-1-eneacetic and 2-Substituted Phenylacetic Acids with Diazodiphenylmethane in Various Solvents

Abstract

The rate constants for the reaction of 2-substituted cyclohex-1-eneacetic and 2-substituted phenylacetic acids with diazodiphenylmethane were determined in various aprotic solvents at 30 degrees C. To explain the kinetic results through solvent effects, the second-order rate constants of the examined acids were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis, and the solvent effects on the reaction rates were analyzed in terms of initial and transition state contributions. The opposite signs of the electrophilic and the nucleophilic parameters are in agreement with the well-known mechanism of the reaction of carboxylic acids with diazodiphenylmethane. The quantitative relationship between the molecular structure and the chemical reactivity is discussed, as well as the effect of the molecular geometry on the reactivity of the examined compounds.