SUMMARY
The selective hydrogenation of dimedone (1) to the corresponding monoketone 2 over palladium and Amberlyst 15® is reported. The product is a synthetic building block for the fragrance and pharmaceutical industry. Advantages of the new catalytic procedure are the high catalyst activity and selectivity, less by-product formation, avoidance of the presence of acid, and consequently, less salt formation due to the omission of a neutralization step. Using a substrate/catalyst ratio of >100 compound 2 can be synthesized in 97% yield at full conversion. Recycling of the catalyst several times has been shown to be feasible without any detectable decrease in selectivity.