Palladium‐Catalyzed Cascade Intramolecular Cyclization/Intermolecular Michael Addition Reaction of Allenyl Benzoxazinones with 3‐Aroylcoumarins

Abstract 4‐Alkyl coumarins and 2‐alkyl quinolines exhibit significant biological activities. Connecting these two molecular frameworks via an alkyl chain represents a promising strategy for developing novel bioactive compounds. However, research in this area remains relatively limited. Recently, a Pd(0) π‐Lewis base‐catalyzed C─C coupling strategy has emerged as an efficient method for coupling such molecules. In this study, we report a palladium‐catalyzed cascade reaction involving intramolecular cyclization and intermolecular Michael addition between allenyl benzoxazinones and 3‐aroylcoumarins. The process initiates with the Pd‐mediated formation of η 2 ‐Pd complexes from allenyl benzoxazinones, which subsequently undergo C─C coupling with 3‐aroylcoumarins, enabling efficient access to a diverse series of 4‐(quinolin‐2‐ylmethyl)coumarin derivatives.