Solvent Free Synthesis of α, á-Bis(substituted-benzylidene)cycloalkanones Using Covalently Anchored Sulfonic Acid on Silica Gel (SiO 2 -R-SO 3 H) as an Efficient and Reusable Heterogeneous Catalyst

We wish to report a mild and efficient Crossed-Aldol reaction for the synthesis of α, ?-bis(substituted-ben- zylidene)cycloalkanones in the presence of catalytic amounts of covalently anchored sulfonic acid onto sil- ica gel under heterogeneous and solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure and work up steps, short reaction times and easy recovery of the catalyst. We have also demonstrated that the catalyst can be reused successfully.