Selective Reduction of the Nitro-group Using Co₂(CO)₈-H₂O

These results indicate that Co₂(CO)₈-H₂O is a versatile reducing system for wide variety of aromatic nitro compounds in the presence of other functional groups. The reaction can easily be applicable to a large scale synthesis of aniline compounds as the reaction set-up, sequence and work-up is simple and straightforward. Therefore this procedure does bear a general use for a large scale preparation of aromatic amines specifically in cases where selective, rapid, mild reduction is required. Recently, we reported a new reducing agent prepared from Co₂(CO)₈ and H₂O for the selective 1,4-reduction of α,β-unsaturated carbonyl compounds as well as a tandem reductive Pauson-Khand reaction. We became interested in the reduction power especially the reactivity and the selectivity of this new reducing agent in reducing other functional groups. Reduction of aromatic nitro compounds to amines is a very useful synthetic transformation for which a vast array of reagents has been developed. Though the most general methodology for this conversion is catalytic hydrogenation as it is an economical and effective method, particularly in large scale reactions, the reaction has a limited utility in the presence of other reducible functional groups