Microwave-Assisted Deoxygenation of Substituted Aromatic Ketones over Commercial Pd/Al2O3

Herein, a study on the deoxygenation of substituted aromatic ketones over commercial Pd/Al2O3 (5 wt %) is reported. The reaction occurs under very mild conditions (120 degrees C, 5 bar H2) in just 2 h using microwaves to enhance the kinetics. Ethanol was found to be the best solvent, while the effect of the substituents was studied over different substrates. On the basis of experimental evidence, a mechanism is proposed in which keto-enol tautomerization enables deoxygenation to the corresponding alcohol followed by direct hydrogenolysis to the alkyl chain.