Benzannulation of phthalic anhydrides with alkynes to polyfunctionalized naphthalenes and phenanthrenes was confirmed to be straightforward using a palladium catalytic system. Sequential liberation of CO2 and CO occurred via oxidative decomposition of anhydride. In the case of 1,8-naphthalenedicarboxylic anhydrides, both aryls were encompassed in the annulation reaction to afford acenaphthylenes.
A palladium-catalyzed multi-component annulation approach towards the synthesis of phenanthrenes
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