Stereo- and regioselective cross metathesis of 3-substituted cyclooctenesAmerican Chemical Society 252nd National Meeting (2016)
Cyclooctenes are known as very useful monomers for ring-opening metathesis polymerization (ROMP). We have previously shown that when allylic substitution is added to these monomers (i.e., 3-substituted monomers), ROMP using Grubbs second or third generation catalysts (G2 or G3) occurs with high E-stereoregularity and head-to-tail regioregularity. We have now demonstrated that polymers made from these 3-substituted cyclooctenes undergo cross metathesis (CM) in the presence of G2 or G3 while maintaining high levels of stereo- and regioregularity. CM of two starting polymers could thereby be utilized to target any intermediate polymer length based on the polymer feed ratio. Additionally, using two different 3-substituents, such as ethyl and acetoxy, a monomodal distribution at an average Mn is observed by size exclusion chromatography within 0.5 h of exposure to G2 or G3. By differential scanning calorimetry, the transition to a single Tg in the resultant copolymer requires roughly 24 h. This difference in time scale is indicative of the formation of multiblock polymer intermediates en route to statistical copolymers.
Publication DateAugust, 2016
Citation InformationMadalyn R. Radlauer, Megan E. Matta and Marc A. Hillmyer. "Stereo- and regioselective cross metathesis of 3-substituted cyclooctenes" American Chemical Society 252nd National Meeting (2016)
Available at: http://works.bepress.com/madalyn-radlauer/17/