CeO ₂-catalyzed transformations of nitriles and amides

Recently, cerium oxides have been extensively used as heterogeneous catalysts for green organic reactions. This review describes recent progress in such reactions, with a focus on our studies on pure CeO ₂-catalyzed reactions of nitriles and amides with nucleophiles (H ₂O, alcohols, and amines). Hydration of nitriles to amides in water, one-pot ester synthesis from nitriles and alcohols, one-pot synthesis of N-alkylamides from nitriles with amines, and synthesis of N-alkylamides from amides and amines (transamidation) are selectively catalyzed by CeO ₂ under aqueous or solvent-free conditions. Mechanistic studies suggest that a cooperation of Lewis acid site (Ce ⁴⁺ cation) and acidbase (CeO) pair site plays essential roles in the catalytic reactions.