Ruthenium Complex Bearing a Hydroxy Group Functionalised N‐Heterocyclic Carbene Ligand – A Universal Platform for Synthesis of Tagged and Immobilised Catalysts for Olefin Metathesis

Six olefin metathesis catalysts, based on a common ruthenium precursor featuring a hydroxy‐substituted N‐heterocyclic carbene ligand, were successfully prepared and fully characterised. As proof‐of‐concept, two of them ([Ru]isonico and [Ru]dmab) were directly immobilised on a solid support. These non‐covalently heterogenised catalysts are efficient in different metathesis reactions and sufficiently stable to be used for repeated runs under batch and continuous flow conditions. In nonpolar media such as n‐hexane, the catalytic character of the metathesis reactions is truly heterogeneous, and the contamination of the products with ruthenium is very low. A ruthenium‐based olefin metathesis catalysts featuring a hydroxy‐substituted N‐heterocyclic carbene ligand is described as a platform for the synthesis of functionalised catalysts through direct acylation of this common precursor. Such complexes have been immobilised on solid support and the corresponding heterogeneous catalysts exhibited a high stability and reactivity both in batch and in flow.