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 β-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: solvent-free conditions, short reaction times, a decreased catalyst loading, a mild reaction temperature, and an easy workup.
Bibliographical noteFunding Information:
This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2006-331-E00438) and the second stage of the Brain Korea 21 Project.
- Pechmann reaction