Abstract
A simple, highly versatile, and efficient protocol for the synthesis of substituted olefins from various aromatic aldehydes and active methylene compounds by Knoevenagel condensation using an efficient, eco-friendly, and recyclable nano-ZnO catalyst in ethanol at a moderate temperature was developed. Due to its large surface area, the nano-ZnO catalyst exhibited an excellent catalytic activity. The advantages of the method included milder conditions, short reaction times, and easy work-up and purification of products by non-chromatographic methods. The catalysts can be recovered for subsequent reactions and reused without any appreciable loss of efficiency.