Silica-Immobilized Second-Generation Hoveyda-Grubbs Catalyst

Significance

Silica-immobilized second-generation Hoveyda-Grubbs catalysts were prepared and found to promote metathesis reactions. Thus, Hoveyda-Grubbs catalyst 1 reacted with silica powder (Fluka silica gel) in toluene at 20 ˚C for 2 h to afford the bright greenish power 2a. The silica pellets catalyst 2b was prepared via a similar protocol using silica pellets instead of silica powder. Ring-opening metathesis polymerization (ROMP) of cyclooctene was carried out with 1 mol% Ru of the silica catalysts 2a and 2b in hexane at 20 ˚C to give polymer 4 in 95 and 98% yield, respectively. Catalyst 2b was separated from the polymer by decantation under air conditions and reused four times without any loss of activity.