Ring opening metathesis mechanism
Grubbs catalyst ring closing mechanism
Dixneuf, J. Laurent, F. Only the unsubstituted bonds are ring-opened it is very difficult to metathesize or ROMP tri- and tetrasubstituted olefins. ROMP is a superior method for making diblock and triblock co-polymers and permits one to tailor the properties of the resulting material. Fensterbank, M. By addition of ferric chloride, a selective aromatization was achieved. First, as the reaction involves a cyclic olefin, the "new" olefin that is generated remains attached to the catalyst as part of a growing polymer chain as is shown below with a generic strained cyclic olefin: The second difference is that the driving force for the ROMP reaction is the relief of ring strain. Mondal, S. Palmisano, A. Bunrit, S. This page was last updated Tuesday, March 31, This document and associated figures are copyright by Rob Toreki or the contributing author if any noted above. Grigg, C. Chain transfer cross metathesis between a growing polymer unit and an adjacent polymer alkene also leads to broadened molecular weights. To prevent backbiting in this or other systems you must make sure your catalyst does not react with internal olefins!
J Mol Cat A: Chemical, All rights reserved. An isomerization-ring-closing metathesis strategy for the synthesis of substituted benzofurans W. The polymers produced in the ROMP reaction typically have a very narrow range of molecular weights, something that is very difficult to achieve by standard polymerization methods such as free radical polymerization.
McDonald, D. For example, consider the synthesis of polyacetylene by ROMP of cyclooctatetraene shown below. Bujok, M.
Laurent, F. However, one has to be a little more careful when selecting a ROMP catalyst. Polshettiwar, R.
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