Methanolysis of ortho- and para-formylbenzenesulfonates in basic media: evidence for the intramolecular nucleophilic catalysis by the carbonyl group

Abstract

Methanolysis of p-methoxyphenyl 2-formylbenzenesulfonate, in the presence of anhydrous potassium carbonate at ambient temperature gives the dimethyl acetal of 2-formylbenzenesulfonic acid in excellent yield. p-Methoxyphenyl 4-formylbenzenesulfonate under identical conditions remains unaffected. These results provide evidence for the catalytic involvement of the neighbouring aldehyde carbonyl group and operation of intramolecular nucleophilic catalysis during the nucleophilic substitution at sulfonyl sulfur.