Synthesis and Characterization of Sterically Enlarged Hoveyda-Type Olefin Metathesis Catalysts

A series of four ruthenium-based olefin metathesis catalysts has been prepared. These new complexes were designed with nanofiltration in organic media in mind; steric enlargement and functionalisation by means of polar ethylene glycol chains were incorporated. New complexes based on the stable 2nd generation Hoveyda-type architecture and featuring substitution either on the NHC backbone or on the N-aryl substituent of the NHC have been prepared and fully characterized. The application of these complexes in a series of olefin metathesis transformations revealed that these modified catalysts retained activity on par with the parent Hoveyda catalyst thus validating the disclosed ligand design.