Highly active ruthenium-based catalyst for metathesis of cyano-contained olefins

Ruthenium benzylidene complex (H2IMes)(2-CH3–C5H4N)(Cl)2RuCHPh [H2IMes = 1,3-bis(2,6-dimethylphenyl)-4,5-dihydroimidazol-2-ylidene] (4), which introduced ortho substituted pyridine as dissociating ligand to weaken Ru–N bond and accelerate initiation through steric hindrance, was prepared by the reaction of (H2IMes)(PPh3)(Cl)2RuCHPh (1) with 2-methylpyridine and proved to exhibit enhanced catalytic activity for cyano-contained olefin metathesis.