Chelation-assisted carbonylation reactions catalyzed by Rh and Ru complexes

This account reviews chelation-assisted carbonylation reactions catalyzed by late transition metals. New carbonylation reactions are achieved with these catalysts in the presence of pyridin-2-ylmethanol and pyridin-2-ylmethylamine. The reactions involve activation of O-H and N-H bonds, coordination of the pyridine nitrogen to Rh being essential for the reaction to proceed. In addition, a new type of carbonylation of the ortho C-H bonds in aromatic amides in which the pyridin-2-ylmethylamino moiety functions as a bidentate directing group, is demonstrated. In this reaction, a dinuclear ruthenium complex was isolated from a stoichiometric reaction of amide and Ru-3(CO)(12), in which amide binds to one Ru atom in the expected N,N fashion and the carbonyl oxygen binds to the other Ru atom as an O-donor. These studies indicate that chelation methodology is useful for new types of carbonylation reaction, which cannot be achieved by non-chelation systems.