A stable ruthenium catalyst for productive olefin metathesis

New ruthenium carbene complexes 5 and 6, containing a rigid bicyclic phosphine moiety, have been prepared, and the structure of 5 has been unambiguously established by single-crystal X-ray diffraction studies. These ruthenium-based complexes show excellent stability to air and moisture, can be recycled by chromatography, and are available from simple precursors. They are efficient catalysts for various metathesis reactions, particularly for applications where high selectivity is required.