Scandium(III) triflate is an excellent catalyst in the von Pechmann condensation. The solvent-free catalytic reactions proceed smoothly with a range of phenols and b-ketoesters in the presence of 10 mol% scandium(III) triflate at 80 C. This simple method affords various 4-substituted coumarins in good to excellent yield and is superior to the classical method in several aspects: solventfree conditions, short reaction times, a decreased catalyst loading, a mild reaction temperature, and an easy workup.

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