Selective Monoarylation of Aromatic Ketones via C-H Bond Cleavage by Trialkylphosphine Ruthenium Catalysts.

A catalyst system consisting of RuHCl(CO)(PiPr3)2, CsF, and a styrene derivative was found to be applicable to selective monoarylation of aromatic ketones via ortho C-H bond cleavage. The reaction of 2'-methoxyacetophenone with arylboronates gave C-H arylation products without cleaving the ortho C-O bond. Acetophenone was also converted to monoarylation products with high selectivity. Cyclohexanone was found to be an effective solvent for the C-H arylation using the catalyst system.