Eliminations from aryl bis(p-chlorophenyl)acetates promoted by R2NH in MeCN. Effects of base-solvent and β-aryl group

Abstract

Elimination reactions of (4′-ClC6H4)2CHCO2C6H3-2-X-4-NO2 promoted by R2NH in MeCN have been studied kinetically. The observed second-order kinetics, Bronsted β = 0.44–0.86 and |βblog| = 0.46–0.69 are consistent with the E2 mechanism. The Bronsted β decreased as the leaving group was made more nucleofugic and the |βlog| increased with a weaker base. Comparison with existing data reveals that the structure of the transition state is relatively insensitive to the base-solvent and β- aryl substituent on the E2 transition state.