18-Electron Ruthenium Phosphine Sulfonate Catalysts for Olefin Metathesis

The first instances of ruthenium
alkylidene complexes based on
chelating phosphine sulfonates are presented. Although these complexes
are formally 18-electron complexes bearing cis phosphines
and cis one-electron donors (sulfonates and chlorides),
they are surprisingly active for ring-closing metathesis, cross-metathesis,
and ring-opening metathesis polymerization, thus highlighting the
unique potential of the sulfonate ligand in the design of a ruthenium
metathesis catalyst.