Intramolecular catalysis of phosphate diester hydrolysis. Nucleophilic catalysis by the neighbouring carboxy-group of the hydrolysis of aryl 2-carboxyphenyl phosphates

Abstract

The hydrolysis of aryl 2-carboxyphenyl phosphate anions is catalysed by the ionised carboxy-group. A rate enhancement of 107–108 is observed, and evidence is presented consistent with a mechanism involving intramolecular nucleophilic catalysis. Salicyclic acid cyclic phosphate is identified as an intermediate on the reaction pathway. The reaction is remarkably stereospecific for displacement of the exocyclic group, and an explanation is suggested involving a quinquecovalent intermediate which cannot undergo pseudorotation.