Air-stable phosphine oxides as preligands for catalytic activation reactions of C-Cl, C-F, and C-H bonds

Studies on the use of easily accessible heteroatom-substituted secondary phosphine oxides as preligands for cross-coupling reactions are described. These air-stable sterically hindered phosphine oxides allow for efficient palladium-catalyzed Suzuki- and nickel-catalyzed Kumada-coupling reactions using electronically deactivated aryl chlorides. In addition, they enable nickel-catalyzed coupling reactions of magnesium organyls with aryl fluorides at ambient temperature, and ruthenium-catalyzed coupling reactions of aryl chlorides via C-H bond activation. Finally, the application of modular diamino phosphine chlorides as preligands for a variety of transition-metal-catalyzed C-C and C-N bond formation reactions employing electron-rich aryl chlorides is presented.