4'-(Hydroxy, chloro, amino, acetoxy and methoxy)-methyl-4, 5'–dimethylangelicins were efficiently and rapidly synthesized via Claisen rearrangement of 4-methyl-7-[4-(hydroxy, chloro, amino, acetoxy and methoxy)-but-2-ynyloxy]-coumarins respectively under microwave irradiation. Prominent among the advantages of this new method are operational simplicity, good yields in short reaction times and easy work-up procedures employed.