Suppression Effect of the Pd/C-Catalyzed Hydrogenolysis of a Phenolic Benzyl Protective Group by the Addition of Nitrogen-containing Bases.

Abstract A mild and chemoselective hydrogenation method using 5% Pd/C for olefin, N -Cbz, benzyl ester and nitro functionalities distinguishing from the benzyl protective group for the phenolic hydroxyl group has been developed by the employment of 2,2′-dipyridyl as an additive. The suppressive effect on the benzyl ether hydrogenolysis was strongly influenced by the sorts of nitrogen-containing bases employed as an additive.