Sukwon Hong

February 18, 2011 - 10:30am
Wright Rieman, Rm. 260
Organic Seminar


CCB Young Investigator Seminar Series presentation by Dr. Sukwon Hong, University of Florida.

Sponsored in part by Organic Syntheses, Inc.

Host: Dr. Lawrence Williams

Talk Title: "Exploring New Ligand Designs for Asymmetric Catalysis"

Abstract:  Novel chiral Co-salen catalysts capable of self-assembly through hydrogen bonding have been developed.  First, a self-assembled dinuclear Co(II)-Salen catalyst featuring the pyridone/aminopyridine H-bonding pair results in significant rate acceleration (48 times faster rate) as well as excellent enantioselectivity (96% ee vs 55% ee) in nitro-aldol reaction, compared to the corresponding monomeric catalyst. [1] Second, bis-urea functionalized salen-Co(III) complexes have been designed to form self assembled structures in solution through self-complementary urea-urea hydrogen bonding interactions.  Bis-urea functionalized salen-Co catalysts result in rate acceleration (up to 14 times) in hydrolytic kinetic resolution of terminal epoxides, compared to the corresponding monomeric catalyst. [2] Detailed kinetic and mechanistic study results will be discussed.

X-ray structure of SA-Salen-Ni Complex

[1] Park, J.; Lang, K.; Abboud, K. A.; Hong, S. Self-Assembled Dinuclear Cobalt(II)-Salen Catalyst Through Hydrogen-Bonding and Its Application to Enantioselective Nitro-Aldol (Henry) Reaction. J. Am. Chem. Soc. 2008, 130, 16484-16485.

[2] Park, J.; Lang, K.; Abboud, K. A.; Hong, S. Self-Assembly Approach toward Chiral Bimetallic Catalyst: Bis-Urea Functionalized (Salen)Cobalt Complexes for the Hydrolytic Kinetic Resolution of Epoxides. Chem.-Eur. J. Early View (DOI: 10.1002/chem.201002600).