Kinetics and mechanism of oxymercuriation of αβ-unsaturated carbonyl compounds
Abstract
The products and the kinetics of methoxymercuriation of a series of αβ-unsaturated ketones and esters have been studied. Whereas the methoxymercuriation of αβ-unsaturated esters is stereospecific, the methoxymercuriation of the ketones leads to mixtures of diastereoisomers. The configuration of the products has been deduced from their 1H n.m.r. spectra on the basis of chemical shifts and proton coupling constants. The results are consistent with the formation of a bridged ‘mercurinium’ ion intermediate. It is suggested that the mixtures of diastereoisomers obtained from the αβ-unsaturated ketones are the result of equilibria established after the oxymercuriation reaction.