Microwave-assisted solvent-free synthesis of α,α′-bis(substituted benzylidine)cycloalkanones catalyzed by /ZrO2and B2O3/ZrO2

Synthetic utility of sulfated and borate zirconia for the synthesis of α,α′-bis(substituted benzylidine)cycloalkanones using microwave irradiation in solvent-free conditions has been investigated. Both sulfated zirconia (SO4 2−/ZrO2) and borate zirconia (B2O3/ZrO2) demonstrated excellent catalytic activity for cross-aldol reaction of cycloalkanones with mono- and poly-substituted aromatic aldehydes. The significance of our finding relates to the minimization of volatile organic solvents, low reaction times, good yield of products, and ease of work up affording the reusability of catalyst.