Selective C=O Reduction in Phthalimide with Nickel(0) Compounds

The catalytic reduction of phthalimide was achieved using nickel catalysts. The use of catalytic amounts (20% mol) of [Ni(COD)(2)] or [(dippe)Ni(mu-H)](2) (1) allowed the monoreduction of phthalimide to yield isoindolinone and benzamide, at 140-180 degrees C and 750 psi of H-2. When the N-H moiety of phthalimide was protected with a trimethylsilyl group, both C=O groups were reduced to yield (trimethylsilyl)isoindoline. However, when a methyl moiety was used as the protecting group, the C=O groups and the aromatic ring were reduced, using rather similar reaction conditions, due to the formation of 5 angstrom (average) nickel nanoparticles.