Ruthenium(II)-catalyzed N-substituted phthalimide synthesis via C–H activation/[3+2] annulation

•Develop an efficient method for the synthesis of N-substituted phthalimides derivatives.•Cheap and environmentally benign Ru(II) was employed as catalyst.•Readily available acids and isocyanates were used as starting materials.•There is no theoretical waste except for water generated in the reaction.

Ruthenium-catalyzed intermolecular [3 + 2] annulation pathway for aromatic acids with isocyanates to afford N-substituted phthalimide in one step is demonstrated, which provides an efficient process to direct preparation of phthalimide from commercially available starting materials and environmentally benign catalysts. This cascade cyclization involves the direct functionalization of an ortho C–H bond and the subsequent intramolecular nucleophilic substitution. There is no theoretical waste except for water generated in the reaction.

Graphical abstractEnvironmentally benign ruthenium-catalyzed one-step intermolecular [3+2] annulation is demonstrated for synthesizing N-substituted phthalimide from commercially available aromatic acids and isocyanates, which involves the direct functionalization of an ortho C–H bond and the subsequent intramolecular nucleophilic substitution.Figure optionsDownload full-size imageDownload as PowerPoint slide