The effect of bound metal ions the reactivity of crown ether-like substrates with hydrolysable rings

Abstract

The rate of hydrogen ion-catalysed hydrolysis of crown ether acetals (1) is decreased on complexing of alkali metal cations, whereas a rate increase is correspondingly observed for the reaction of a crown ether ester (2) with hydroxide ions; both effects are semi-quantitatively intelligible on a simple electrostatic model and require the relative permittivity relevant to the interaction of the charges to be that of the bulk solvent.