Mono‐ and Bisionic Mo‐ and W‐Based Schrock Catalysts for Biphasic Olefin Metathesis Reactions in Ionic Liquids

• Published in: Chemistry : a European journal Vol. 24; no. 50; pp. 13336 - 13347
• Main Authors: Schowner, Roman, Elser, Iris, Toth, Florian, Robe, Emmanuel, Frey, Wolfgang, Buchmeiser, Michael R.
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 06.09.2018; Wiley Subscription Services, Inc
• Subjects: biphasic catalysis; Catalysis; Catalysts; Chemistry; Chemistry, Multidisciplinary; Chlorobenzene; Contamination; Coordination compounds; Heptanes; Ionic liquids; Ions; Metathesis; molybdenum; olefin metathesis; Physical Sciences; Pyridinium; Science & Technology; Solvents; Toluene; tungsten; olefin metathesis; N-HETEROCYCLIC CARBENE; CROSS-METATHESIS; OPENING METATHESIS; ALKENE METATHESIS; COMPLEXES; REACTIVITY; tungsten; NATURAL-PRODUCT SYNTHESIS; RING-CLOSING METATHESIS; biphasic catalysis; MOLYBDENUM IMIDO ALKYLIDENE; ionic liquids; molybdenum
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201802472

An extensive series of the first ionic Mo‐ and W‐based Schrock‐type catalysts based on pyridinium and phosphonium tagged aryloxide ligands were prepared. Bisionic complexes of the general formula Mo(Imido)(CHR)(OR′)2(OTf)2 and monoionic monoaryloxide pyrrolide (pyr) (MAP‐type) catalysts [M(Imido)(CHR)(OR′)(pyr)+][A−] were successfully employed and tested in various olefin metathesis benchmark reactions under both, homogeneous and biphasic conditions using pyrrole and, for the first time with Schrock‐type catalysts, ionic liquids as the polar phase. Productivities under biphasic conditions up to several thousand turn overs were achieved and are comparable to those obtained in reactions carried out in chlorobenzene or toluene. Metal contamination in the nonpolar product‐containing heptane phase was <2 ppm. The first ionic Mo‐ and W‐based Schrock‐type catalysts were prepared from betaine‐type ligands and tested in various olefin metathesis benchmark reactions under both homogeneous and biphasic conditions using ionic liquids. Virtually metal free (>2 ppm) products were obtained.