Kinetics ring-opening metathesis

Langsdorf BL, Zhou X, Lonergan MC. Kinetic study of the ring-opening metathesis polymerization of ionically functionalized cyclooctatetraenes. Macromolecules 2001 34 2450-2458. 

The ring-opening metathesis polymerization of dicyclopentadiene was monitored by ultrasonic spectroscopy.16 The thermoset poly(dicyclopentadiene) is formed by ringopening and cross-linking in a reaction injection molding system. A reaction cell with a plastic window was constructed for use with pulse echo ultrasonic spectroscopy. Realtime measurements of density, longitudinal velocity, acoustic modulus and attenuation were monitored. Reaction kinetics were successfully determined and monitored using this technique. 

The molybdenum complex Mo(NAr)(CHCMe2Ph)[(3)-Me2SiBiphen] 43 was used for catalytic asymmetric olefin metathesis reactions such as desymmetrization of trienes, kinetic resolution of allylic ethers, tandem catalytic asymmetric ring-opening metathesis/cross-metathesis. Interestingly, tandem catalytic asymmetric ring-opening... 

RCM may proceed by the formation of a series of metallocyclobutane intermediates that break apart to form new alkenes and new metal carbenes, which propagate the reaction. The cycloalkene product accumulates as the reaction proceeds since the reverse reaction, ring-opening metathesis, is kinetically disfavored. 

Muhlebach, A., Bernhard, P., Buhler, N., Karlen, T., Ludi, A., Ring opening metathesis polymerization of bicyclo[2.2.1]hept-2-ene and exo,exo-5,6-bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]hept-2-ene using Ru(II) and Ru(III) complexes polymerization kinetics and ruthenium content in polymers, J. Mol. Catal. 1994, 90 143-156. 

Monitoring and evaluation of the crossover reaction in ring-opening metathesis polymerization (ROMP) via MALDI methods were reported recently by Binder et al. [97]. The crossover reactions as well as the polymerization kinetics of the various monomers were studied in the presence of different catalysts by kinetic analysis and MALDI MS. Whereas the classical kinetic analysis enabled the qualitative monitoring of the chain-growth reaction, MALDI method allowed the monitoring of the reaction directly at the point of the crossover reaction, thns enabling a better evalnation of the different monomers and catalysts employed in the polymerization reactions. 

C.S. Daeffler, G.M. Miyake, J. Li, R.H. Grubbs, Partial kinetic resolution of oxanorbomenes by ring opening metathesis polymerization with a chiral mthenium initiator. ACS Macro Lett. 3, 102-104 (2014)... 

Part 2 includes chapters on specific classes of cyclic monomers and their polymerization mechanisms and kinetics, their main (co)polymer architectures and related products, as well as current and future applications. Hence, siloxane-con-taining and sulfur-nitrogen-phosphorus-containing polymers are described in Chapters 3 and 4, respectively, while the polymerization of cyclic depsipeptides, ureas and urethanes, of polyethers and polyoxazolines, and of polyamides are detailed in Chapters 5, 6 and 7, respectively. Chapters 9, 10, 11 and 12 include details of polyesters prepared from either P-lactones, from dilactones, from larger lactones and from polycarbonates, while the polymerization of cycloalkanes is described in Chapter 13. It should be noted that, slightly out of place . Chapter 8 covers the subject of ring-opening metathesis polymerizahon. 

Crotonaldehyde, hydrogenation of, 43-48 Cubane, isomerization of, 148 Cyclic dienes, metathesis of, 135 Cyclic polyenes, metathesis of, 135 Cycloalkenes, metathesis of, 134-136 kinetic model, 164 ring-opening polymerization, 143 stereoselectivity, 158-160 transalkylation, 142-144 transalkylidenation, 142-144 Cyclobutane configuration, 147 geometry of, 145, 146 Cyclobutene, metathesis of, 135 1,5,9-Cyclododecatriene, metathesis of, 135... 

Because of its favorable kinetic and thermodynamic properties, norbomene can be polymerized with simple transition-metal halogenides.99 116 Even RuC13, which is not active in other metathesis reactions, is effective in the ring-opening polymerization of norbomene.117118 Developments in the early 1990s include the use of... 

Hocker, H., Ring-opening Polymerisation of Cycloolefins by Means of Metathesis Catalysts Kinetic and Thermodynamic Effects on the Product Distribution , Makro-mol. Chem. Macromol. Symp., 6, 47-52 (1986). 

Kinetic resolntion of cyclic allylic ethers can be performed by asymmetric Zr-catalyzed carbomagnesation. Six-, seven-or eight-membered ethers can readily be resolved by the Zr-catalyzed protocol (with ee between 81 to 99%). As an example, the tandem Zr-catalyzed kinetic resolution followed by a Ru-catalyzed ring-opening/ring-closing metathesis affords chiral chromenes with high optical purity (ee > 99%). ... 

Totally intramolecular enyne metathesis Diels-Alder sequences have been demonstrated (e.g., the conversion of 244 into 246). Enyne RCM of substrate 247 affords stereochemically pure 248 due to kinetic resolution during metathesis.A process equivalent to enyne metathesis that proceeds through a non-carbene mechanism has been demonstrated using platinum chloride as a catalyst. In addition to routine observations, some other interesting side-reactions have been noted (Scheme 29). Competitive cross-metathesis with ethylene and intramolecular enyne metathesis were observed in the treatment of substrate 249 with catalyst 16 and ethylene.Cyclopropane ring opening was observed in the attempted enyne metathesis of substrate 253, resulting in alkylidenecyclopentene 254. 

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