Green and Efficient Synthesis of Bidentate Schiff Base Ru Catalysts for Olefin Metathesis

A simple, green synthetic protocol to bidentate Schiff base
substituted ruthenium carbene complexes is described. These
complexes are potent catalysts for olefin metathesis, but the
original synthetic route employs the Schiff base ligands in
the form of highly toxic thallium(I) salts. The new protocol
involves a two-step, quasi-one-pot approach and silver(I)
carbonate as base. The target ruthenium carbene complexes
are obtained in yields that are similar to, or better than, those
of the original protocol.