Synthesis and Structural Characterization of a cis-beta Ru(CO)2-Schiff Base Complex and Its Use in Asymmetric Cyclopropanation and Amination Reaction

The study on catalysis of salen-derived metal complexes has been carried out almost exclusively with their trans-isomers, even though recent studies disclosed that cis-isomers show unique reactivity that cannot be attained with other metal complexes [1]. We report here on the synthesis and the crystal structure of a new cis-beta ruthenium carbonyl complex of Jacobsen’s Schiff base (H2L). All the spectroscopic features of the Ru(CO)2L complex are indicative of a cis disposition of the two carbonyls. The proposed cis-beta structure has been confirmed by an X-ray analysis. Ru(CO)2L has been successfully employed as catalysts in asymmetric cyclopropanation reactions. Since our group has recently reported the use of aryl azides as aminating agents [2], we next examined the catalytic activity of Ru(CO)2L for the amination reaction of olefins with organic azides and the results will be discussed.