Ru(II)-catalyzed oxidative spiroannulation of 2-arylphenols with alkynes via a C-H activation/dearomatization strategy.

An intermolecular spiroannulation reaction of appropriately substituted 2-arylphenols with internal alkynes has been developed by using a Ru(II) catalyst and an oxidant. This transformation was realized by a phenol-directed C-H activation, migratory insertion of the alkyne, and subsequent dearomatization of the phenolic ring, providing a broad range of highly functionalized spirocyclic compounds in moderate yields with high regioselectivity.