Functionalized regio-regular linear polyethylenes from the ROMP of 3-substituted cyclooctenes

We demonstrated that the ring-opening metathesis polymerization (ROMP) of 3-substituted cyclooctenes bearing polar substituents allows the synthesis of highly regio- and stereo-regular polymers. A series of polyalkenamers with 90–99 % head-to-tail/trans configuration were synthetized in good yields (33–87 % yield). Upon saturation of the backbone using diimide, these polymers represent a class of linear polyethylene derivatives where the polar side chain is located on every eighth carbon. The thermal properties of both the saturated and unsaturated polymers depend strongly on the size and polarity of the functional side groups. The results presented here demonstrate that the 3-substituted cyclooctenes can be used not only for the synthesis of precisely functionalized polyethylene derivatives, but also to participate in the ring-opening metathesis copolymerization with unfunctionalized cyclic olefins to generate copolymers with tunable properties.