Selective hydrogenation of 4-(6-methoxy-2-naphtyl)-3-buten-2-one to Nabumetone

Low loading copper catalysts allows hydrogenation of a,b-unsaturated ketones to the corresponding saturated ones with selectivity up to 99%. Moreover, the selectivity can be tuned toward different products only by playing with the support acidity or the experimental conditions. By using a 8% Cu/SiO2 catalyst the final reduction step in the synthesis of the anti-inflammatory drug Nabumetone1 can be carried out with selectivity >98% under mild conditions with good productivity and without any additives. No leaching of the metallic phase was observed, the catalyst is not pyrophoric even in the reduced state and it can be reused.