The effects of added ammonium chloride in the reductive amination of some carbonyl compounds over Ru and Pd catalysts

The reductive amination of acetophenone, (+)-camphor, and 5α-cholestan-3-one over Ru and Pd metals as well as their carbon-supported catalysts gave corresponding amines together with alcohols as by-products. However, we found that the corresponding amines are selectively synthesized by the addition of ammonium chloride to the reaction system with depression of the formation of alcohol, as exemplified with acetophenone. Although alcohols are usually not formed over Pd with alicyclic ketones, the alcohols formation was effectively depressed over Ru in the presence of ammonium chloride. The effects of the additive on the stereoselectivity of the formation of amines are also discussed in the cases of (+)-camphor and 5α-cholestan-3-one.