Synergic effects between ancillary N-heterocyclic carbenes [(1,3-bis(2,4,6-trimethylphenyl)-1,3-imidazoline-2-ylidene or 1,3-bis(2,6-diisopropylphenyl)-1,3-imidazoline-2-ylidene] and chelating benzylidene ether ligands were investigated by studying initiation rates and kinetic profiles of Hoveyda-Grubbs (HG) type Ru complexes. A newly designed Ru-benzylidene-oxazinone precatalyst 4 was compared with Grela and Blechert complexes bearing modified isopropyloxy chelating leaving groups and with the standard HG complex to understand how the ancillary and the leaving ligands interact and influence the catalytic activity.
- N-heterocyclic carbenes
- Olefin metathesis
- Kinetic studies
- Hoveyda-Grubbs type complexes
- Chemical stability