Crossed Aldol Condensation using Anion Exchange Resin as Solid Base Catalyst.

Crossed aldol condensation was effectively carried out in the presence of an anion exchange resin as solid catalyst. For this condensation, the basic strength of the anion exchange resin was adjusted by substituting the Cl- constituent of the resin with OH- for an appropriate quantity of the resin. This anion exchange resin, having taken on the proper basicity, was found to quite effectively catalyze the crossed aldol condensation reaction of benzaldehyde, saturated and unsaturated aliphatic aldehyde and terpenoid aldehyde with acetone. In view of this favorable finding, this anion exchange resin was applied to and found quite effective for the synthesis of 5,5-dimethyl-3-styryl-2-cyclohexen-1-one (12), 5-(2,2,3-trimethyl-3-cyclopenten-1-yl)-3-penten-2-one (15), and pseudoionone (17).