Hexyltriphenylphosphonium Bromide as an Absolutely Chemoselective Ionic Liquid Catalyst in the Three-Component Reaction of Aryl Aldehydes, Acetophenones and Malononitrile

Hexyltriphenylphosphonium bromide (HTPB) is used as an efficient ionic liquid catalyst in the chemoselective addition of malononitrile to carbonyl group moiety of chalcones through the three-component reaction of aryl aldehydes, acetophenone derivatves, and malononitrile to produce (E)-2-(1,3-diarylallylidene)malononitriles at ambient temperature. The method is simple, solvent-free, environmentally friendly, and gives excellent yields in a short reaction times.