Nucleophilic ring opening of some epoxy ketones

ABSTRACT

The reaction rates of some trans P-substituted epoxybenzalacetopheaones 1[a-h] with thiophenolate and p-nitrothiophenolate have been measured at different temperatures. The reaction is unidirectional and gives W - thioaryloxy-p-substituted acetophenones and p-substituted benzaldehyde. Effect of the substituents has been analysed in terms of Hammett linear free energy relationship. The values of P and activation parameters delta Hz number sign and delta S number sign are in accordance with the proposed bimolecular S[N][2]mechanism