Silicium-Supported Metathesis Catalysts

Significance

The Grubbs-Hoveyda-type ruthenium complexes were immobilized onto Si-based inorganic composites. Ortho-isopropyloxy styrene 3 was anchored onto Si supports to give the immobilized ligands 5A, 5B, 5B _cap (after complete si­lanol capping), 5C, and 5D. The Si-supported ligands 5 were treated with the Grubbs complex 1a or 1b to give the corresponding Si-supported Grubbs-Hoveyda-type ruthenium complexes 6. Catalytic activity as well as the recyclability of the Si-supported complexes 6 were examined for the ring-closing metathesis (RCM) of dienes 7a-c. Representative results are shown above. Of the series of the Si-supported Ru complexes, 6Ab and 6Bb bearing the SIMes ligand were found to promote the RCM reactions with good recyclability.