Synthesis of functionalized alpha-pyrone and butenolide derivatives by rhodium-catalyzed oxidative coupling of substituted acrylic acids with alkynes and alkenes.

The straightforward and efficient synthesis of alpha-pyrone and butenolide derivatives has been achieved by the rhodium-catalyzed oxidative coupling reactions of substituted acrylic acids with alkynes and alkenes, respectively. Some alpha-pyrones obtained exhibit solid-state fluorescence.