This insertion was proposed as a way to stop metathesis reactions for kinetic analysis to study reaction mechanism, but it has evolved into a practical procedure to both stop a metathesis reaction and to facilitate purification of the organic products.
Ring Opening Metathesis requires a strained ring to proceed. Follows cross metathesis. An example reaction of a ROMP reaction can be seen below:
Olefin Metathesis 1950s – In the presence of various organometallo compounds, olefin metathesis (where the R groups of olefins were swapped with the other)
Polymerization & Metathesis Catalysis Polymerization is the reaction of an unsaturated organic reactant, typically a C=C, with itself over and over again.
Modeling of Ru and Fe based olefin metathesis Michael T. Feldmann Richard P. Muller William A. Goddard, III Materials and Process Simulation Center, Caltech.
In year two, we have used this reaction development tostop first generation catalysis (one paper published) and to expand thereaction scope in enyne metathesis, publishing three new methodology papers.
We realized that these two characteristics fit nicely with our desire to stop metathesis reactions and also to remove the ruthenium at the end of the reaction.
Because we felt that this would be generally helpful to the synthesis community, we invested time to study this for a variety of metathesis reactions and several different ruthenium(II) carbene complexes.
This insertion was proposed as a way to stop metathesis reactions for kineticanalysis to study reaction mechanism, but it has evolved into a practicalprocedure to both stop a metathesis reaction and to facilitate purification ofthe organic products.
In addition, the fast quenching procedure is being used to studyrapid enyne metathesis employing very reactive phosphine-free variations of theGrubbs catalyst.
We will interpret these data in terms of our ongoing syntheticstudies in ene-yne metathesis, and collaterally use this knowledge to developnew applications of the ene-yne metathesis.In year two, we have also employed our mechanisticknowledge of the enyne metathesis to develop three new reactions.
Olefin metathesis is used to form polymers to create materials for bathroom sinks, stronger baseball bats, tank armor, Hepatitis C and Osteoporosis drugs, candles and for pest control.
Ring Expanding Enyne MetathesisIn conclusion, the second year of this PRF grant hasresulted in a relatively advanced understanding of fundamental reactivity ofthe Grubbs ruthenium carbenes in the presence of strong donor ligands.
Thisinformation is vital for a successful kinetic study for fast enyne metathesesand those involving internal alkynes where IR cannot be used to follow thereaction kinetics.
Note: LuRn=CH2 is a simplified drawing of the Ruthenium Grubbs catalyst. The catalyst used in the reaction is recreated at the end of the reaction (RuLn=CH2). “M” in the mechanism refers to the metal present in the catalyst for Olefin Metathesis (usually Ru, W, or Mo).
Last, our evolving mechanistic knowledge has resulted in thedevelopment of synthetic methods employing enyne metathesis for ring expandingreactions and for difficult cross enyne metathesis.