Conducting organic transformations in water displays many benefits over classical synthesis in organic solvents. Water is non-toxic, environmentally benign and vastly abundant. Apart from the economic and ecological advantages, aqueous media as solvents are also attractive due to their high heat capacities and their low miscibility with organic solvents which forms the basis of methodologies for catalyst recycling. Over the past four decades metathesis has evolved to become a highly valuable and versatile tool in organic and polymer synthesis. In particular during the last ten years, Ru-based Grubbs-type metathesis catalysts have significantly expanded the application spectrum due to their substrate tolerance and inertness towards air and moisture. Several water-soluble catalysts have been synthesized and successfully employed in aqueous ROMP and ROM reactions. These catalysts are coordinated by water-soluble phosphine ligands providing less active and thermally less stable “first generation” Grubbs-type catalysts. In our research, we target the synthesis of watersoluble N-heterocyclic carbene (NHC) ligands for the application in aqueous metathesis reactions. Substitution of one phosphine versus one NHC-ligand provides “second generation” Grubbs-type catalysts which should display significantly improved catalytic performances. We are currently developing various synthetic procedures which could provide NHC ligand derivatives for the application in aqueous metathesis.
- Ru-based Grubbs-type metathesis catalysts,
- N-heterocyclic carbine,
Available at: http://works.bepress.com/hans-joerg_schanz/77/