Iridium-Catalyzed Enantioselective C-H Functionalization Reactions of Alkynes

NSF Abstract for Public Dissemination – Professor Yiming Wang With the support of the Chemical Synthesis Program in the Division of Chemistry, Professor Yiming Wang at the University of Pittsburgh is studying the development of catalysts (additives that help to make a reaction proceed more efficiently and/or faster) based on iridium for the selective preparation of chemical compounds with well-defined configurations in three-dimensional space. This approach will use relatively simple chemical building blocks containing triple-bonded hydrocarbons, known as alkynes, as starting materials for the synthesis of products that contain new bonds to a variety of elements including sulfur, silicon, germanium, and tin, as well as molecular groupings that contain fluorine which are found in various pharmaceutical candidates. That substrates that are related to the products from these studies are valuable precursors to a range of other molecules makes this work relevant to several industries including those focused on polymers and materials, pharmaceuticals, and fine chemicals. In addition, the Wang group will also use the developed reactions for the chemical synthesis of several biologically active compounds that have been isolated from nature and thave the potential to be used as therapeutics. In addition to improving our ability to access complex molecules, the PI will broaden the teaching of metal-catalyzed reactions to students in both lecture and laboratory settings, as well as perform outreach to the broader community to disseminate the impact of transition metal catalysis on society with a focus on sustainability. Professor Yiming Wang’s lab will investigate the use of chiral, enantiopure phosphoramidite complexes of iridium for the C–H functionalization of alkynes at the propargylic position in an enantioselective manner. This approach will deliver highly enantioenriched propargylic thioethers, silanes, germanes, and stannanes along with several classes of compounds bearing fluorination. These studies will be broadly impactful on industries that make products ranging from polymers to medicines. This technology will also be applied to C–C bond formation and is expected to find utility in the enantioselective synthesis of a range of pyrrolizidine alkaloids, as well as cyclopropanes and heterocyclic compounds bearing multiple stereocenters. 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.