CAREER: Iridium Catalysts for the Activation and Functionalization of Ethereal Substrates

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Ether molecules are ubiquitous in the chemistry that powers modern society. Simple ethers find applications as solvents, motor fuel additives, and as precursors to polymeric materials such as plastics and epoxies. Complex ethers are used to synthesize carbohydrates required for modern biochemical applications. A defining characteristic of ethers is their low reactivity. However, this useful property limits options for their further chemical modification and thus, usefulness. With support from the Chemical Catalysis program of the National Science Foundation, this research project is developing new catalytic methods to enable ether reactivity. Professor Schley and his group at Vanderbilt University are exploring new methods for ether activation designed to address challenges unique to the utilization of both simple and complex ethers. The team is enriched by strong connections between Vanderbilt and local community colleges in the greater Nashville area. Professor Schley is organizing an outreach program designed to promote undergraduate research opportunities for community college students. Internship opportunities for current or recent community college graduates to conduct summer research at Vanderbilt University are also being created.The stability of the ether functional group with respect to attack by oxidants, strong bases, and nucleophiles is a valuable property in many respects, but limits avenues for direct ether derivatization. As a result, despite the availability, affordability, and low toxicity of simple alkyl ethers, they have been primarily limited to low-value applications. Similarly, the harsh stoichiometric methods used for ether C-O cleavage limits compatibility with complex polyether-containing molecules including carbohydrate derivatives. Through this project the Schley research group is exploring two modes for iridium-mediated electrophilic ether activation involving ether dehydrogenation to electrophilic alkoxycarbenes and ether silylation to give silyloxonium ions. These intermediates are activated towards nucleophilic cleavage reactions of the integral carbon-oxygen bond and represent mechanistically distinct routes to selective, catalytic ether cleavage reactions. This research is being pursued in tandem with outreach to local community colleges in the Nashville area. As a former community college student himself, Professor Schley is piloting an outreach program aimed at disseminating information about undergraduate research opportunities for community college students in Tennessee.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.