The mechanism of acyl phosphonate reactions. Part I. The kinetics of the solvolyses of benzoyl and p-toluoyl phenylphosphonates in aqueous dioxan

Abstract

Rate constants have been determined for the neutral hydrolysis of benzoyl phenylphosphonate in 5, 20, and 40% aqueous dioxan and p-toluoyl phenylphosphonate in 20% dioxan. Acid catalysis, salt effects, and the addition of nucleophiles have been investigated in 20% dioxan at 295·5 K. It is concluded that the mechanism of hydrolysis is bimolecular addition to the acyl carbon atom to form a tetrahedral intermediate prior to phosphonate ion elimination.