[ONLINE] CiQUS Lecture: Asymmetric Amplification Using Dynamic Helical Macromolecule PQX as a Catalyst Platform

Abstract:

Asymmetric amplification is the chemical process in which subtle imbalance of chirality eventually leads to the formation of highly homochiral products.  In asymmetric catalysis, it has been recognized that even chiral catalysts with low enantiomeric excesses result in the formation of highly enantioenriched products.¹ Such asymmetric amplification in catalysis is highly attractive from not only the fundamental standpoint, but also practical viewpoint, because it makes free from use of enantiopure chiral source in asymmetric catalysis.  Moreover, the concept of asymmetric amplification may be extended to utilization of weak, nonbonding chiral molecular interactions as a source of chirality.

In this presentation, new possibilities of asymmetric amplification in catalysis is discussed on the basis of the use of helical poly(quinoxaline-2,3-diyl) (PQX) as a platform of chiral catalysts of which helical chirality is dynamic.  The majority-rule effect in the helical macromolecular scaffold allows synthesis of single-handed helical structure even with chiral starting material with low enantiomeric excess.²  The unique scaffold enables use of substoichiometric amounts of chiral guest with low ee to induce single-handed helical conformation.³  Moreover, utilization of chiral dispersion force as an exclusive source of chirality in highly enantioselective asymmetric catalysis is demonstrated by using macromolecular catalysts having no internal chiral source.⁴

References

(1)   B. L. Feringa, R. A. van Delden, Angew. Chem., Int. Ed. 1999, 38, 3418-3438.  

(2)   Y.-Z. Ke, Y. Nagata, T. Yamada, M. Suginome, Angew. Chem., Int. Ed. 2015, 54, 9333-9337.  

(3)   T. Yamamoto, R. Murakami, S. Komatsu, M. Suginome, J. Am. Chem. Soc. 2018, 140, 3867-3870.

(4)   Y. Nagata, R. Takeda, M. Suginome, ACS Central Science 2019, 5, 1235-1240.

Biosketch:

Michinori Suginome is a Professor at the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University since 2004. He graduated from Department of Synthetic Chemistry, Faculty of Engineering, Kyoto University, where he received his B.S. (1988) and Ph.D. (1993) and worked as an Assistant Professor (1993–2002) and an Associate Professor (2002–2004). He has been the recipient of the Chemical Society of Japan Award for Young Chemist (1999), Nagoya Silver Medal (2005, Banyu Life Science Foundation International), Mukaiyama Award (2005, Society of Synthetic Organic Chemistry, Japan), and JSPS Prize (2010, Japan Society for the Promotion of Science), the Chemical Society of Japan Award for Creative Work (2013), the Humbold Research Award (2015), the Molecular Chirality Award (2020), the ACS Arthur C. Cope Scholar Award (Late Career, 2021) and the Award of the Society of Polymer Science, Japan (2021). His research interests include (1) Helical Polymers, (2) Element-Boryl Addition, (3) Boron-Based Synthesis, (4) C-H Functionalization, among others.

More info - Group website: 

The Suginome Research Group - Laboratory of Organic System Design