Reductive cross-coupling reactions of unsaturated compounds

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The Chemical Synthesis Program of the Chemistry Division supports the project by Professor Gojko Lalic and his group at the Department of Chemistry, University of Washington. Professor Lalic is developing a new type of reactions for organic synthesis. The goal of this research is to provide a more efficient alternative to traditional methods for making molecules by the coupling of two or more molecular fragments (reactions referred to as cross-coupling reactions). Cross-coupling reactions improve the efficiency of synthetic efforts relative to building molecules one step at a time. Cross-coupling reactions are commonly used in the preparation of fine chemicals and pharmaceuticals and thus, are relevant to advanced manufacturing. The new type of cross-coupling reactions enables the use of readily available compounds as starting materials. The new reaction provides economic and environmental advantages over the existing state-of-the-art. Dr. Lalic and his group have established an outreach program with elementary and high school schools that promote science and technology. A wide range of activities, including regular participation in science classes at local high schools, are designed to reach students underrepresented in science and promote careers in science, technology, engineering and mathematics disciplines.In this project, two types of reductive cross-coupling reactions of unsaturated compounds are being developed. Syn-selective hydrofunctionalization of alkynes are being used to enable the hydroarylation, hydroalkenylation, and hydroalkylation of alkynes. All three transformations involve hydrocupration of alkynes followed by palladium-catalyzed functionalization of the alkenyl copper intermediate. The key for the cooperative action of copper and palladium catalysts is a phase-separation of two incompatible components; one from a catalytic cycle of a copper catalyst and one from the catalytic cycle of a palladium catalyst. The phase separation prevents a series of side reactions that otherwise dominate the outcome of the reaction. This strategy is general and can be used to develop other processes that require cooperative catalysis of two incompatible catalytic cycles. The Lalic group is also developing methods for anti-selective hydrofunctionalization of terminal alkynes. These transformations are based on an initial cross coupling followed by the selective semireduction of the alkyne intermediate. Another important aspect of the work this project is the continued commitment of Professor Lalic and his group to promoting science in a broader community. A major focus of these efforts is a collaboration with local programs and institutions that specialize in supporting participation of underrepresented minority students and women in STEM fields.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.