A palladium-catalyzed multi-component annulation approach towards the synthesis of phenanthrenes

An efficient palladium-catalyzed three-component cascade reaction has been developed for the facile construction of phenanthrene frameworks. The transformation is driven by a controlled reaction sequence of Suzuki–Miyaura coupling followed by the insertion of alkynes, and finally, annulation to yield phenanthrene derivatives via C–H activation. This methodology is able to accommodate a variety of substrates and affords the anticipated products in good to excellent yields.