Mechanism-driven Development of Mo catalysts for Z-selective Isomerization of Terminal Olefins

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With the support of the Chemical Catalysis program in the Division of Chemistry, Graham Dobereiner of Temple University is studying how to rearrange specific chemical bonds in organic molecules using catalysts. The rearranged molecules are potentially useful for making pharmaceuticals and other fine chemicals. Besides seeking greater control of the phenomenon of catalysis, the project team is working to replace rare platinum-group metals typically used as catalysts with more earth abundant alternatives. The project will strengthen interactions between academic chemistry and industry and help train students for careers in medicinal chemistry via collaboration between investigators at Temple University and GlaxoSmithKline. The PI will bolster STEM (science, technology, engineering and mathematics) participation in the Philadelphia region by involving students in a regular, regional meeting for inorganic chemists. The PI will also support secondary STEM education through interactive activities with students from School District of Philadelphia (SPD) high schools.This project at Temple University is building organomolybdenum catalysts for the Z-selective isomerization of terminal alkenes - to date a rare synthetic transformation. The hypothesis is that molybdenum complexes with sterically demanding hemilabile ligands can be used to control stereochemical outcomes more effectively than state-of-the-art catalysts. To test the hypothesis, complexes with varying ligand steric properties will be compared in their isomerization selectivity, scope, and activity. Catalytic mechanisms will be probed experimentally and computationally to refine the working model of Z-selectivity. New catalysts under development will be employed in tandem transformations, targeting high-value organic compounds with industrial relevance. The blending of stoichiometric studies, computational design and kinetic analysis will inform models for isomerization selectivity to advance a rational design concept for homogeneous catalysis. The development of these models will serve as a framework for controlling stereochemical outcomes of alkene-focused reactions, an area of critical importance to synthetic organic chemistry. Besides having a significant impact on catalyst design, the methods developed will be valuable in the production of cis-alkenes and their derivatives, with potentially important applications in drug development to be exploited via a previously established collaboration with GlaxoSmithKline.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.