Improved preparation of an olefin metathesis catalyst bearing quaternary ammonium tag (FixCat) and its use in ethenolysis and macrocyclization reactions after immobilization on metal-organic framework (MOF)

An optimized synthesis of a key intermediate Ru4 in substantially improved yield of 50% and in scale up to 1 gram was described. Such obtained Ru4 was quantitatively converted into useful quaternary ammonium tagged catalyst Ru1 (FixCat) and mmobilized in a metal-organic framework (MOF). Next, two challenging applications, not studied previously with hybrid Ru1@MOF catalyst were attempted. In the case of the RCM reaction yielding a macrocyclic musk lactone, heterogeneous Ru1@MOF exhibited under high-dilution conditions high resistance towards unwanted C-C double bond migration, thus offering superior selectivity as compared to analogous mogeneous catalysts. In ethenolysis of ethyl oleate, Ru1@MOF exhibited only slightly better selectivity as compared to well-known general-purpose Hoveyda-Grubbs SIMes and SIPr catalysts, while it was not able to challenge the benchmark Bertrand-Hoveyda-Grubbs catalyst in this transformation