Design of imidazolium- and pyridinium-tagged Ruthenium pre-catalysts for olefin metathesis in ionic liquids

摘要

Olefin metathesis transformations in Room Temperature Ionic Liquids (RTILs) media is a promising alternative to promote greener and economic processes in the elaboration of various building blocks. Nevertheless, the ideal combination of both an efficient and highly recyclable catalytic system authorising to minimize the Ru-contamination in the metathesis products is often delicate. To reach these two challenging features, imidazolium- and pyridinium-tagged Ru-alkylidene pre-catalysts have been designed and fully evaluated in various Ring-Closing Metathesis (RCM) and Cross-Metathesis (CM) reactions. This article highlights several strategies concerning ionic-tagged Hoveyda-Grubbs boomerang type complexes, notably in the quest to find an optimal compromise between the catalyst activity, the catalyst lifetime and its recovery in RTILs media.