Arene-Free Ruthenium(II/IV)-Catalyzed Bifurcated Arylation for Oxidative C-H/C-H Functionalizations.

Experimental and computational studies provide detailed insight into the selectivity- and reactivity-controlling factors in bifurcated ruthenium-catalyzed direct C-H arylations and dehydrogenative C-H/C-H functionalizations. Thorough investigations revealed the importance of arene-ligand-free complexes for the formation of biscyclometalated intermediates within a ruthenium(II/IV/II) mechanistic manifold.