Intramolecular proton-transfer catalysis of nucleophilic catalysis of acetal hydrolysis. The hydrolysis of 8-dimethylamino-1-methoxymethoxynaphthalene

Abstract

The cleavage of the conjugate acid of the title aryl methyl acetal is catalysed efficiently by the neighbouring Me₂NH⁺ group, and also by added nucleophiles. Hydrolysis and nucleophilic catalysis involve a common mechanism, with obligatory but weak bonding to water or the added nucleophile in the transition state. The key to efficient intramolecular proton-transfer catalysis appears to be an intramolecular hydrogen bond between the general acid and the leaving-group oxygen which is strong in the product and transition states, but weak or absent in the ground state.