Ruthenium-Catalyzed Ortho C-H Arylation of Aromatic Nitriles with Arylboronates and Observation of Partial Para Arylation.

Ruthenium-catalyzed C-H arylation of aromatic nitriles with arylboronates is described. The use of RuH2(CO){P(4-MeC6H4)3}3 as a catalyst provided higher yields of the ortho arylation products than the conventional RuH2(CO)(PPh3)3 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.