Lithium hydroxide: A simple and an efficient catalyst for Knoevenagel condensation under solvent-free Grindstone method

Synthesis of arylmethylidenes from araldehydes and active methylene compounds catalyzed by catalytic amount of lithium hydroxide (LiOH·H2O) in the absence of a solvent under Grindstone method is reported. The reactions go to completion within 1–5 min and give products in excellent yields at 26 °C.