Suzuki-Miyaura and Buchwald-Hartwig Cross-Coupling Reactions Utilizing a Set of Complementary Imidazopyridine Monophosphine Ligands

Palladium-catalyzed Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions have become indispensable tools in the synthesis of otherwise inaccessible compounds because of the efficient, catalytic nature of these styles of reactions. The development of novel monophosphine ligands to achieve the cross-coupling of substrates that are generally unreactive under standard conditions has developed into an extremely important area of research in the field of organometallic chemistry. Herein, we show the use of an imidazopyridine monophosphine ligand JagPhos I in the Suzuki-Miyaura palladium-catalyzed cross-coupling reaction to deliver sterically-hindered biaryls and unsymmetrical biheterocycles. We also report the scope and limitations of imidazopyridine monophosphine ligand JagPhos II in the Buchwald-Hartwig amination reactions of (hetero)aryl halides with anilines, secondary amines, and primary amines. We described the scope and limitations of palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of (hetero)aryl halides with (hetero)arylboronic acids with our optimized phosphorus imidazo[1,5-a]pyridine ligand JagPhos I. Successful reactions were obtained with a series of (hetero)aryl halides with (hetero)arylboronic acids to furnish sterically-hindered biaryls and biheterocycles. We also presented the scope and limitations of palladium-catalyzed Buchwald-Hartwig amination reactions of (hetero)aryl halides with anilines, secondary amines, and primary amines with our optimized phosphorus imidazo[1,2-a]pyridine ligand JagPhos II. Sucessful reactions were obtained with a series of (hetero)aryl halides with various anilines and secondary amines. image