Polystyrene-Supported DABCO: an Environmentally Friendly Heterogeneous Catalyst for Knoevenagel Condensation

Over the past few years, there have been increasing recognitions that polymer-supported reagents and catalysts are important tools for organic synthesis (due to simplifiedrecovery, reusability, and the potential for incorporation in continuous reactors and microreactors) [1]. The Knoevenagel condensation is one of the most useful andwidely employed methods for carbon–carbon bond formation in organic synthesis. It is effected by treating a carbonylcompound with an active methylene compound in the presence of a catalyst. Several types of catalysts were introduced previously for Knoevenagel condensation [2-4]. However, many of the reported catalysts suffer from the drawbacks such as generation of environmentally perilouswaste material, tedious work-up, complicated operations, and the use of hazardous, difficult to handle or unreusable catalysts. In this study, we now wish to introduce polystyrenesupported DABCO (PS-DABCO) as an effective heterogeneous catalyst for the Knoevenagel condensation