Divergent Access to 1‑Naphthols and Isocoumarins via Rh(III)-Catalyzed C–H Activation Assisted by Phosphonium Ylide

Rh-catalyzed C–H activation of phenacyl phosphoniums in coupling with α-diazocarbonyl compounds has been realized with the assistance of a mutifunctional phosphonium ylidic directing group, providing expedient accesses to 1-naphthols and isocoumarins. Switchable synthesis of 1-naphthols and isocoumarins was realized by substrate control, where these transformations were enabled by initial C–H activation and subsequent intramolecular Wittig reaction or nucleophilic C–O formation.