Pd/C-catalyzed chemoselective hydrogenation in the presence of a phenolic MPM protective group using pyridine as a catalyst poison

Employment of a Pd/C-pyridine combination as a catalyst is a very useful method for the selective removal (hydrogenolysis) of phenolic O-benzyl, N-Cbz and benzyl ester protective groups and for the selective hydrogenation of nitro and olefin functions of phenol derivatives protected with the MPM group. These discriminatory results are apparently attributable to the effect of pyridine. The MPM group could be extensively applied to chemoselective hydrogenation as a protective group for phenolic hydroxyl functions.