New Lewis Bases for Chemical Catalysis

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New Lewis Bases for Chemical CatalysisThe Chemical Synthesis Program of the Chemistry Division supports the project by Professor Karl Scheidt. Professor Scheidt is a faculty member in the Department of Chemistry at Northwestern University. He is developing new classes of chemical catalysts. Chemical catalysts enable the efficient and sustainable synthesis of new small molecules and materials that are important for pharmaceutical, material science, and biomedical research communities. Because of their utility in these areas, catalysts derived from Lewis bases (molecules capable of donating an electron pair), and in particular N-heterocyclic carbenes (NHCs), have been of particular interest, and work with these systems has exploded during the last decade. In this effort, NHCs have frequently been employed as ligands to generate chiral metal complexes as well as catalysts in their own right in the absence of a transition metal (metal free or organocatalysis). Yet in spite of this effort, little is known about how NHC-based catalysts can be tuned in order to optimize their performance in new classes of reactions. For this reason, the Scheidt group is exploring a novel family of NHC-transition metal complexes as catalysts. These new systems can be used to systematically study how changes in structure alter the properties and catalytic behavior of the NHC. The work has broad implications for how new catalysts in the NHC-family will be designed in the future. The project lies at the intersection of organic, asymmetric synthesis, and catalysis and thus is excellent for training and education in interdisciplinary science. In terms of broader impacts of the project, Dr. Scheidt is actively engaged in outreach activities focused on underrepresented group recruitment into the STEM fields.The sustainability and advancement of society relies on new discoveries based on molecular science. One such discovery is the general utility of new electron-rich molecules (Lewis bases) as catalysts for a broad range of reactions, many of which have implications for materials, biological, and pharmacological efforts. In the specific work being pursued, Dr. Scheidt is using a novel family of N-heterocyclic carbine (NHC)-metal complexes to both catalyze new asymmetric bond forming reactions and to provide new mechanistic insights into how the nucleophilicity of an NHC-catalyst can be tuned. The specific synthetic targets selected for the effort are alpha-boryl amines. Since there are major limitations to the currently available methods for alpha-borylation reactions that have hampered the use of the chosen targets as synthetic building blocks, the choice of the alpha boryl amines as targets nicely highlights the broad synthetic implications of the catalysts being developed. The mechanistic insights being gained center on advancing our knowledge of Lewis base and transition metal catalysis and determining the structure-reactivity relationships that govern catalyst behavior. Dr. Scheidt's outreach activities build on his research and target the improved recruitment of underrepresented groups into the chemistry doctoral program at Northwestern University.