Olefin Metathesis with Immobilized Grubbs Catalyst

Significance

Grubbs I catalyst in ionic liquid [hmim]PF₆ was immobilized in pores of Al₂O₃ to give Ru-supported ionic liquid ([hmim]PF₆) on Al₂O₃ (Ru-SILC/Al₂O₃, Ru loading = 0.03 mmol/g). Ring-closing metathesis of diallyl compounds 1 and 3 was carried out in the presence of 5 mol% Ru of Ru-SILC/Al₂O₃ to give the corresponding product 2 (82% yield) and 4 (96% yield), respectively. In contrast, olefin cross-metathesis took place with compound 5 to give a dimerized 6 (68%). In the reaction of 1, Ru-SILC/Al₂O₃ was recovered by filtration and reused four times without significant loss of its catalytic activity (average 80% yield for 5 times).