Premium
Cationic Group VI Metal Imido Alkylidene N ‐Heterocyclic Carbene Nitrile Complexes: Bench‐Stable, Functional‐Group‐Tolerant Olefin Metathesis Catalysts
Author(s) -
Benedikter Mathis J.,
Musso Janis V.,
Frey Wolfgang,
Schowner Roman,
Buchmeiser Michael R.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202011666
Subject(s) - chemistry , nitrile , carbene , cationic polymerization , metathesis , ligand (biochemistry) , lewis acids and bases , catalysis , medicinal chemistry , thio , alkoxide , organic chemistry , polymer chemistry , combinatorial chemistry , biochemistry , receptor , polymerization , polymer
Despite their excellent selectivities and activities, Mo‐and W‐based catalysts for olefin metathesis have not gained the same widespread use as Ru‐based systems, mainly due to their inherent air sensitivity. Herein, we describe the synthesis of air‐stable cationic‐at‐metal molybdenum and tungsten imido alkylidene NHC nitrile complexes. They catalyze olefin metathesis reactions of substrates containing functional groups such as (thio‐) esters, (thio‐) ethers and alcohols without the need for prior activation, for example, by a Lewis acid. The presence of a nitrile ligand was found to be essential for their stability towards air, while no decrease in activity and productivity could be observed upon coordination of a nitrile. Variations of the imido and anionic ligand revealed that alkoxide complexes with electron‐withdrawing imido ligands offer the highest reactivities and excellent stability compared to analogous triflate and halide complexes.