Well-Defined Ruthenium(II) Carboxylate as Catalyst for Direct C–H/C–O Bond Arylations with Phenols in Water

The ruthenium(II) carboxylate complex [Ru(O₂CMes)₂(<i>p</i>-cymene)] enabled efficient direct arylations of unactivated C–H bonds with easily available, inexpensive phenols. Extraordinary chemoselectivity of the well-defined ruthenium catalyst set the stage for challenging C–H/C–O bond functionalizations to occur under solvent-free conditions as well as in water, and allowed first direct C–H bond arylations with user-friendly diaryl sulfates as electrophiles