Synthesis of Benzo[1,6]naphthyridinones Using the Catellani Reaction

An intramolecular version of the Catellani reaction was optimized for one-step synthesis of bulky N-substituted benzo[1,6]naphthyridinones with good to excellent yields. The optimized reaction of N-substituted o-bromobenzamides with 4-bromoquinolines features a wide substrate scope and yields of up to 98%. The employment of aryl bromides under carefully optimized conditions instead of the usual aryl iodides enhances the scope of the reaction.