Phosphine Oxides as Preligands in Ruthenium-Catalyzed Arylations via C−H Bond Functionalization Using Aryl Chlorides

[reaction: see text] The use of air-stable, electron-rich phosphine oxides as preligands allows for unprecedented general ruthenium-catalyzed arylation reactions of pyridines and imines through C-H-bond activation using aryl chlorides. The catalytic system derived from a sterically hindered adamantyl-substituted phosphine oxide proves highly efficient and tolerates a number of important functional groups.