Metathesis Catalysts with Fluorinated Unsymmetrical NHC Ligands

The synthesis of new fluorinated ruthenium­(II) carbene second-generation precatalysts with unsymmetrical N-heterocyclic carbene ligands has been developed. The reaction profiles of these complexes have been studied in RCM with model substrates such as diethyl diallyl- and allylmethallyl-malonate, and CM model reaction of allylbenzene with 1,4-diacetoxybut-2-ene. In olefin metathesis reactions, the new fluorinated second-generation Grubbs complexes exhibit comparable activity with respect to commercially available Grubbs catalysts. On the other hand, in RCM reactions, the Hoveyda-type catalysts present a latent character, which is not present in the classical second-generation Hoveyda catalyst.