Synthesis of Stilbene Derivatives via Phosphine-Catalyzed Cascade [2+4] Annulation/Decarboxylative Aromatization of Yne-Enones with α-Pyrones

Despite significant advances in phosphine catalysis for synthesizing diverse cyclic frameworks, phosphine-catalyzed benzannulation reactions remain largely underexplored. In this work, we report a phosphine-catalyzed cascade [2+4] annulation/decarboxylative aromatization reaction between yne-enones and α-pyrones, which provides access to a wide range of functionalized stilbene derivatives in moderate to high yields (up to 98%). The reaction exhibits scalability and allows facile derivatization of products, highlighting its practical utility. A proposed mechanism outlines a stepwise annulation pathway and further underscores the unique reactivity of yne-enones in phosphine-catalyzed transformations.