Mechanism of the Oxygen Exchange Reaction of n-Butyl Methyl Sulfoxide in Sulfuric Acid

Abstract

Abstract Mechanistic investigations of the concurrent oxygen exchange and racemization reactions of 18O-labeled and optically active n-butyl methyl sulfoxide in sulfuric acid of various concentrations have been carried out. The kinetic data were analyzed in the light of kex/krac values, activation parameters, correlations between the rates and acidity functions, etc. The results seem to suggest that the reaction proceeds through an A-1-like route to afford a cation radical (–\overset+·S–) or a dication (–\overset++S–) intermediate, followed by a fast nucleophilic attack of water to give the starting sulfoxide.