A series of ruthenium complexes, RuHCl(CO)(PAr 3 ) 3 and RuH 2 (CO)(PAr 3 ) 3 , containing various triarylphosphines were synthesized. Screening of these complexes as catalysts for direct arylation of sterically congested ortho C−H bonds of aromatic ketones improved the yields of the arylation products.

Ruthenium-catalyzed C-H arylation of aromatic nitriles with arylboronates is described. The use of RuH(CO){P(4-MeCH)} as a catalyst provided higher yields of the ortho arylation products than the conventional RuH(CO)(PPh) catalyst. The arylation takes place mostly at the ortho positions, but unprecedented para arylation was also partially observed to give ortho,para diarylation products. In addition to C-H bond cleavage, the cyano group was also found to function as a directing group for cleavage of C-O bonds in aryl ethers.