Some reactions of enol-lactones with metal alkoxides

The reactions of various alkyl 5-oxo-2,5-dihydrofuran-2-ylideneacetates and related enol-lactones with sodium alkoxides in alcohols have been studied. Four types of compounds have been characterized, each as the major product, depending on the concentration of alkoxide, the reaction time and the temperature. 4-Methylcyclopentene-1,3-dione and 4,5-dimethylcyclopentene-1,3-dione have been prepared by short syntheses.