Steric effects in the hydrolysis of formaldehyde methyl aryl acetals

Abstract

2-Methoxymethoxy-3-methylbenzoic acid, 2-methoxymethoxy-3-nitrobenzoic acid, 1-methoxymethoxy-2-naphthoic acid, and 2-methoxymethoxyisophthalic acid undergo intramolecularly catalysed and specific hydrogen ion-catalysed hydrolysis more rapidly than 2-methoxymethoxybenzoic acid, probably as a result of steric acceleration. 2-Methoxymethoxy-1-naphtoic acid undergoes an intramolecularly catalysed hydrolysis about five times more slowly than 2-methoxymethoxybenzoic acid, possibly as a result of steric hindrance to the carboxyl group taking up the most favourable conformation for proton transfer to the acetal oxygen.