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(O(2)CMes)(2)(p-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.