Molybdenum-Based Complexes with Two Aryloxides and a Pentafluoroimido Ligand: Catalysts for Efficient Z-Selective Synthesis of a Macrocyclic Trisubstituted Alkene by Ring-Closing Metathesis


  • Financial support was provided by the NIH (GM-59426). We thank J. Yuan for synthesis of a bispyrrolide complex, M. Yu for helpful discussions and Boston College Research Services for providing access to computational facilities.


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Olefin metathesis catalysts for controlling the formation of trisubstituted macrocyclic Z alkenes have been developed. The most effective complexes are Mo alkylidenes with a pentafluorophenylimido group and two large aryloxide ligands. The macrocyclic lactone precursor to anticancer agents epothilones B and D is obtained in 73 % yield and 91 % Z selectivity in less than 6 hours at room temperature.