Synthesis and Reactivity of Olefin Metathesis-Catalyzing Ruthenium Complexes with a Selenoether Moiety in the Benzylidene Ligand

A Hoveyda-Grubbs (HG)-type olefin metathesis complex with a selenoether moiety at the terminal of phenoxy moiety was synthesized. The complex showed a Se-coordination to the ruthenium center, resulting in its higher thermostability than the parent HG catalyst. The Se-coordinative property enhanced product yields in the ring-closing metathesis of N-tosyldiallylamine in the presence of methanol. The large activation enthalpy observed in the reaction with butyl vinyl ether indicated an increased contribution of “dissociative mechanism” during the initiation of the catalytic cycle. Introducing coordinative atoms or functional groups at the terminal of the phenoxy moiety is a useful strategy to regulate the thermostability of HG-type olefin metathesis catalysts.