Synthesis of Isoindolones from Imines and ortho-Iodobenzoyl Acid Chlorides

Significance

Reported is the synthesis of iso­indolones from the reaction of imines with ortho-iodo acid chlorides in the presence of phenyl­lithium. The reaction is proposed to proceed by attack of the imine nitrogen lone pair on the acid chloride to give the intermediate A shown above. This then undergoes lithium-halogen exchange and cyclization to form the isoindolone products. The reaction conditions as shown are optimal as both reacting the imines with the acid chlorides at ambient temperature and quenching the reaction at -78 ˚C gave worse yields.