Ruthenium Olefin Metathesis Catalysts Bearing a Macrocyclic N‐Heterocyclic Carbene Ligand: Improved Stability and Activity

Formation of sterically hindered C−C double bonds via catalytic olefin metathesis is considered a very challenging task for Ru catalysts. This limitation led to the development specialised catalysts bearing reduced N-heterocyclic carbene (NHC) ligands that are active in such transformations, yet significantly less stable as compared general purpose To decrease small-size NHC susceptibility decomposition, new ligand was designed, which two aryl arms were tied together by C-8 alkyl chain. The installation this macrocyclic on ruthenium centre formation an catalyst (trans-Ru6). Interestingly, complex undergoes transformation into isomer Cl cis-arrangement (cis-Ru6). These isomeric complexes exhibit similarly high thermodynamic stability, different application profiles catalysis.