Ruthenium Olefin Metathesis Catalysts Containing Fluoride

The reaction of the ruthenium complex <i>cis-</i><b>Caz-1</b> with silver fluoride affords the first example of an active olefin metathesis precatalyst containing fluoride ligands. The cis geometry of the precursor complex is key to the successful fluoride exchange reaction. Computational studies highlight the stability of the new Ru–F species, due to push–pull interactions between fluoride and L-type ligands (L: <i>N</i>-heterocyclic carbene, phosphite). Insights into the isomerization process from <i>trans</i>-<b>Caz-1</b> to <i>cis</i>-<b>Caz-1</b> are given. Fluoride exchange reactions were performed involving <i>cis-</i> and <i>trans</i>-<b>Caz-1</b> complexes. Catalytic tests showcase the excellent activity of the Ru–F containing complexes