Olefin Metathesis with Immobilized Grubbs Catalyst

Abstract

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).