L-proline-catalyzed Knoevenagel reaction promoted by choline chloride-based deep eutectic solvents

Knoevenagel condensation of acetylacetone and aromatic aldehyde catalyzed by L-proline in the choline chloride-based deep eutectic solvents was achieved. High yields are up to 96.6%. Mild reaction conditions, enhanced rates, improved yields, recyclability of deep eutectic solvents containing L-proline, and reagents’ reactivity which is different from that in standard organic solvents are the remarkable features observed in deep eutectic solvents. The deep eutectic solvents containing catalyst was recycled in four subsequent runs with no decrease in activity.