Abstract Triphenylphosphane (TPP) has been utilized as a novel and efficient catalyst for the Knoevenagel condensation of aldehydes with acidic methylene compounds such as ethyl cyanoacetate and malononitrile to afford substituted olefins. The reaction proceeds smoothly under mild and solvent-free conditions and the products are obtained in excellent yields with an E-geometry. This method is applicable for a wide range of aldehydes including ...