Efficient, durable and reusable olefin metathesis catalysts with high affinity to silica gel

The new Scorpio type olefin metathesis catalysts with very high affinity to silica gel are reported. After completion of the reaction, those complexes can be efficiently separated from reaction product by direct filtration of reaction mixture through a short pad of silica gel. Products obtained by this methodology are contaminated with low amounts of residual ruthenium. Especially, catalyst (H2IPr)(Cl)2RuC(H)(C6H4OR) (5b, R=CH(Me)(C(O)N(Me)OMe) exhibited very high activity and could be easily recovered and reused. Additionally, this catalyst was found to be effective already at 0.1a0.5 mol % and showed good compatibility with environmentally benign solvents.