The Influence of Phosphane Ligands on the Versatility of Ruthenium-Indenylidene Complexes in Metathesis

The aim of the present study is to develop readily available and stable pre‐catalysts that could be easily prepared on large scale from simple starting materials. Based on the hypothesis that substitution of classical PCy3 with phosphanes of varying electron‐donating properties could be a straightforward manner to improve catalytic activity, a methodical study dealing with the effect of phosphane fine‐tuning in ruthenium–indenylidene catalysts was performed. Challenged to establish how the electronic properties of para‐substituted phosphane ligands translate into catalyst activity, the versatile behaviour of these new ruthenium–indenylidene complexes was investigated for a number of metathesis reactions. Ringmaster: A simple synthetic route leads to a series of [RuCl2(NHC)(P(p‐RC6H4)3)(Ind)] (Ind=indenylidene) complexes that has been evaluated in a number of olefin metathesis reactions. The optimised catalysts have been identified for ring‐closing metathesis, ring‐rearrangement metathesis, ring‐opening metathesis polymerisation and cross‐metathesis reactions.