Tetramethylguanidium-based ionic liquids as efficient and reusable catalysts for the synthesis of biscoumarin at room temperature

Abstract

In this work, a basic ionic liquid, tetramethylguanidium acetate ([TMG][Ac]), was found to be an efficient catalyst for the one-pot preparation of biscoumarins through a domino Knoevenagel–Michael reaction at room temperature. This novel catalytic system avoids the utilization of volatile organic solvents and has excellent tolerance to various functional groups on substrates. The convenient preparation, excellent catalytic efficiency, good reusability and the perspective in scale-up reactions make this catalyst intriguing in industrial applications.