Palladium on Carbon: An Efficient, Heterogeneous and Reusable Catalytic System for Carbonylative Synthesis of N-Substituted Phthalimides

The application of palladium on carbon (Pd/C) as a heterogeneous recyclable catalyst was investigated for the double carbonylation of o-dihaloarenes with amines providing excellent yield of N-substituted phthalimides in shorter reaction time as compared to earlier reported homogeneous protocols. Furthermore, the scope of the developed protocol was applied for the synthesis N-substituted phthalimides from o-halobenzoates and o-halobenzoic acid via a single step carbonylative cyclization reaction. The developed methodology describes an efficient one-step approach for the synthesis of an important class of heterocycles and tolerates a wide variety of functional groups. It circumvents the use of phosphine ligands with an additional advantage of catalyst recyclability for up to eight consecutive cycles.