Ruthenium Complexes of κ(P)- and κ(P)-η⁶-Coordinated KITPHOS Monophosphines: Efficient Catalysts for the Direct Ortho Arylation of 2-Phenylpyridine and <i>N</i>-Phenylpyrazole with Aryl Chlorides

Thermolysis of the P-coordinated KITPHOS monophosphine complex [(p-cymene)­RuCl2(KITPHOS)] in chlorobenzene at 120 °C resulted in displacement of the p-cymene to afford [{κ­(P)-η6-KITPHOS}­RuCl2], the first example of a constrained-geometry complex in which the κ­(P)-bonded diphenylphosphino group and the η6-coordinated proximal phenyl ring are connected by an unsaturated two-carbon tether; both complexes form efficient catalysts for the direct ortho arylation of 2-phenylpyridine and N-phenylpyrazole with a range of aryl chlorides.