Michinori Suginome; Department of Chemical Science and Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan

"Helically Dynamic Macromolecular Catalyst: Asymmetric Amplification and Beyond"

The exciting development of homogeneous asymmetric catalysis in the past half century has relied on the discovery of catalyst structures with non-racemizable (static) molecular chirality.  A contrasting idea is to utilize achiral catalysts to which one of the chiral “conformations” is selectively induced thermodynamically by external chiral sources through weak non-bonding interactions.  Such catalysts may open up new possibilities in asymmetric synthesis, leading for example to the direct use of abundant natural compounds as non-bonding chiral sources.  To realize this scenario, we picked up the helical macromolecular scaffolds, which enables amplification of weak chiral non-bonding interactions to induce pure helical conformations, achieving highly enantioselective catalytic reactions in the presence of chiral solvents or additives as chiral sources.  With such macromolecular catalysts, enantio-amplifying catalysis has been developed, where low enantiopurity in the chiral sources is amplified to higher enantiopurity in the reaction products.  Our ongoing effort on the establishment of self-inductive asymmetric catalysis shall also be discussed in the seminar.