The Grotjahn lab has developed catalysts 11 and 22 (see figure 1) that are highly selective in the production of (E) alkenes from terminal alkenes. Currently, there are several alkene isomerization catalysts that convert terminal alkenes to internal (E) alkenes relatively selectively, but fewer that select for (Z) alkenes. An unmet need is to have a catalyst that makes (Z) alkenes that tolerate polar functional groups (e.g., alcohol and acid OH groups). Cyclopentadienyl (Cp)-catalyst 11 produces a mixture of internal (E) isomers, while pentamethylcyclopentadienyl (Cp*)-catalyst 22 selectively produces (E)-2 alkenes in up to ca. 95% yield. We hypothesize that the high (E)-selectivity originates from the bifunctionality of the phosphine ligand. A potential approach to reversing selectivity is to further modify the Cp ligand to incorporate even bulkier R groups and change the position of the nitrogen base. Furthermore, the use of our newly designed Cp ligands to make iridium-based anticancer agents4 to attempt to significantly reduce cancer’s ability to become resistant to small-molecule therapy will be discussed. The synthesis and characterization of functionalized cyclopentadienyl ligands 3-5 (figure 2), their respective ruthenium and iridium complexes, as well as their efficacy toward selective alkene isomerization and cancer therapy, will be presented.

Toward (Z)-selective alkene isomerization catalysts and potential anti-cancer agents

254th National Meeting (2017)

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