ORGN 200

We have been studying the development of new asymmetric two-center catalysis using rare earth alkoxides and bifunctional sugar and related ligands. As a result, we have found a dynamic structural change in chiral rare earth complexes, resulting in a functional change of the complexes. The representative examples are shown below.

After extensive investigation, the catalyst 3 was found to show higher reactivity than 1 in desymmetrization of meso-aziridines with TMSCN to give beta-cyanoamides with better ees. Much to our surprise, the absolute configuration of the products obtained by 1 or 3 was opposite. In addition to the result mentioned above, cyanosilylation of ketones, Strecker reaction of ketoimines, aziridine opening reaction with TMSN₃, and amination using the catalyst 5 will be discussed.