MECHANISM OF ALKALINE HYDROLYSIS OF HINDERED AROMATIC ESTERS, THE BAL2 MECHANISM

Abstract
Kinetic and isotopic exchange data employing H2O18 are presented to establish the bimolecular alkaline hydrolysis with alkyol–oxygen fission (BAL2) for the highly hindered ester methyl 2,4,6-tri-t-butylbenzoate. Methyl 2-methyl-4,6-di-t-butylbenzoate also cleaved predominately by alkyl–oxygen fission. Other hindered esters, methyl 2,4,6-trimethylbenzoate and methyl 2,5-di-t-butylbenzoate, hydrolyzed by the usual acyl–oxygen fission.