Self-Assembled Catalysts for Asymmetric Ring Opening Reactions

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This project will develop novel dinuclear catalysts for asymmetric ring opening reactions such as hydrolytic kinetic resolution (HKR) of terminal epoxides. It employs a highly attractive supramolecular approach which enables rapid construction of multinuclear systems in solution via self-assembly of monomeric units. It aims to develop a highly efficient, green process of HKR of epoxides by enabling solvent-free conditions, very low catalyst loading and catalyst recovery/recycle. First, new Schiff base ligands capable of self-assembly through urea-urea hydrogen bonding will be designed and synthesized. Second, the effectiveness of the self-assembled dinuclear catalysts in hydrolytic kinetic resolution of epoxides will be evaluated. Third, detailed self-association studies will be conducted on the bis-urea functionalized Schiff base metal complexes in solution to investigate the correlation between self-assembly and HKR reaction rate. In addition, organometallic gelation will be explored by introducing additional noncovalent bonding interactions to the bis-urea functionalized Schiff-base metal complexes. With the support of this award from the Chemical Synthesis Program, Professor Sukwon Hong, of the Department of Chemistry at the University of Florida, is developing highly efficient, environmentally friendly processes to convert inexpensive feedstocks to valuable synthetic building blocks under solvent free conditions using small amounts of recyclable catalysts. The proposed research takes a highly innovative approach by merging two different disciplines of chemistry: supramolecular chemistry with transition-metal catalyzed transformations. This interdisciplinary strategy using hydrogen bonding to assemble metal catalysts will provide a new efficient way to bring two metal active sites in close proximity which is a prerequisite for the bimetallic transformations to occur. This novel strategy can be applicable to a wide range of asymmetric reactions and can have a significant impact on the development of more efficient, environmentally friendly industrial processes for important chiral molecules. In addition, this project will provide an excellent opportunity to educate and train undergraduate and graduate students including underrepresented groups owing to its multidisciplinary nature.