Functional Group-directed Ortho-arylation of Aromatic Rings Catalyzed by Transition Metal Complexes

Ortho selective direct arylation reactions have been developed using coordination of functional groups to metal complexes. The reaction of 2-arylpyridines with arylstannanes in the presence of rhodium complexes afforded the desired ortho arylated products efficiently. The use of aryl halides also afforded the ortho arylated products by use of ruthenium catalyst. The ruthenium-catalyzed arylation was successfully expanded to 2-alkenylpyridines affording (Z)-beta-arylated products selectively. Allylic acetates can be also used in the ruthenium-catalyzed direct coupling reaction of 2-arylpyridines giving the ortho allylated products. On the other hand, the reaction of 2-aryloxazolines with certain allylic acetates gave homo coupling products at their ortho positions.