Olefin metathesis in room temperature ionic liquids using imidazolium-tagged ruthenium complexes

New recyclable imidazolium-tagged ruthenium catalysts have been developed to perform olefin metathesis in room temperature ionic liquids (RTILs). High level of recyclability combined with a high reactivity were obtained in the ring-closing metathesis (RCM) of a variety of di- or tri-substituted and/or oxygen-containing dienes. Extremely low residual ruthenium levels were detected in the RCM products (average of 7.3 ppm per run). Several examples of olefin cross-metathesis (CM) have been also studied.

This work reports the development of efficient imidazolium-tagged ruthenium catalysts to perform metathesis reactions in ionic liquids. Whereas a high level of recyclability combined with a high reactivity were obtained with the first generation catalyst 8, the second generation of N-heterocyclic carbene ruthenium complex 9 appeared to be more suitable to perform ring-closing metathesis reactions of less reactive substrates.Figure optionsDownload as PowerPoint slide