Palladium(II)-Catalyzed Oxidative Dearomatization of Free Naphthols with Two Alkyne Units

Readily available 2-naphthols undergo [2 + 2 + 1] spiroannulation reactions with alkynes in the presence of a PdII catalyst and an oxidant. This process relies on C–H functionalization and naphthyl ring dearomatization at the 1-position of 2-naphthols to provide a variety of spirocyclic compounds. Using alkyl–aryl alkynes as the coupling partners led to regioisomeric mixtures in favor of the head-to-tail isomer bearing a quaternary carbon stereocenter.