Synthesis of 5-fluro-1,3-dioxin-4-ones : noval alternatives to α-fluorianted acyl ketenes

Fluorination of 5,6-unsubstituted 1,3-dioxin-4-ones and their 6-substituted derivatives by molecular fluorine followed by treatment with an appropriate organic base affords the title compounds, which can be converted either into heterocyclic compounds or into acylacetic acid derivatives having a fluorine atom