Applications of the Olefin Metathesis Reaction

First FT-Raman and 1H NMR comparative investigations in ring opening metathesis polymerization

“…3) is irrefutable proof that the much less exploited Raman methodology is a valuable tool for monitoring ROMP kinetics, reliably comparing with kinetics [44,45] from NMR spectroscopy. Useful information from the vast library of existing NMR data on ROMP of a variety of cyclic monomers [14,15,46] could thus be transferred to Raman, in anticipation of new results.…”

“…It is the reaction of choice to access diversely functionalized polymers in high demand due to their unique characteristics. Materials ranging in properties from soft rubber to hard and tough thermoplastics and highly cross-linked thermosets can be prepared by this chemistry [14,15]. The burgeoning area of ROMP-based ''designer materials'' needs to always find an efficient solution for reconciling the high reaction rates in ROMP with the precise control over polymer chain lengths.…”

Oxo and imido/imido exchange and C–H activation reactions based on pentamethylcylopentadienyl imido tantalum complexes

“…Interest in the synthesis and isolation of transition metal imido [1] complexes was prompted by the use of imido substituents as 'protecting ligands' in many early transition metal alkylidene complexes, extensively applied as catalysts in olefin metathesis [2] and ring-opening metathesis polymerization [3] processes. However, the imido group is not only an unreactive spectator ligand but a highly nucleophilic center which can react with metal coordinated unsaturated molecules to which the imido group is easily transferred.…”

Stereoretentive Olefin Metathesis: An Avenue to Kinetic Selectivity

“…[47] These investigations were aimed at exploring the stereochemistry of the metallacycle and how it may affect the stereochemistry of the olefin products. As various olefins were examined, it was reported that the stereochemistry of the reactant olefin could sometimes influence the stereochemistry of the product, even when using the same catalyst for either E-or Z-olefins.…”

“…However, 2,5-dimethyl-3-hexene was always formed with exceptional levels of trans-selectivity, due to the large groups residing equatorial on the metallacyclobutane. [47,55] Ultimately, they concluded that retention of stereochemical configuration of an olefin through metathesis was not a general feature of olefin metathesis, thus more selective catalysts must be designed.…”