Facile in situ generation of highly active (arylimido)vanadium(V)–alkylidene catalysts for the ring-opening metathesis polymerization (ROMP) of cyclic olefins by immediate phenoxy ligand exchange

Highly active catalysts for the ring-opening metathesis polymerization (ROMP) of cyclic olefins (norbornene, cyclopentene, cycloheptene) can be generated in situ by premixing V(CHSiMe₃)(NC₆F₅)(O-2,6-ⁱPr₂C₆H₃)(PMe₃)₂ (1) with 1.0 equiv. of C₆F₅OH or C₆Cl₅OH via the immediate phenoxy exchange; the activity was affected by the kind of phenol added [activity (TOF) in the ROMPs of norbornene: 46 200 min⁻¹ (upon addition of C₆F₅OH) vs. 37.3 min⁻¹ (by 1)].