Preparation and reactions of pyridones: steric and electronic effects on cycloadditions with 2(1H)-pyridones

Abstract

The reactions of a series of substituted 2(1H)-pyridones with dimethyl butynedioate have been studied. Cycloadditions across the 3,6-positions can be observed in certain instances and are particularly favoured where steric buttressing occurs between the substituent groups of the starting pyridones. The pyridone could not be induced to react with simple olefins, either by intermolecular or, via incorporation of alkenyl substituents, by intramolecular processes. From the results it is shown that 2-pyridones can be encouraged to behave as reactive classical dienes in cycloaddition reactions.