In(OTf)3 as a powerful and recyclable catalyst for Pechmann condensation without solvent

In(OTf)3 plays the role of a Lewis acid catalyst in the Pechmann condensation of phenols with β-ketoesters under solvent-free conditions to give coumarin derivatives. This novel and inexpensive method has advantages such as short reaction time, excellent product yields, and avoids the use of organic solvents in agreement with green chemistry principles. Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding coumarins at 80 °C. The catalyst can be recovered after the reaction, and reused with only a slight decrease in the yield.

Graphical AbstractVarious coumarin derivatives have been efficiently synthesized by the In(OTf)3-catalyzed Pechmann condensation reaction of various phenols and β-ketoesters under solvent-free conditions. This novel and inexpensive method has advantages such as short reaction time, excellent product yields, and avoiding the use of organic solvents in agreement with green chemistry principles.Figure optionsDownload as PowerPoint slide