| Summary: | Epoxide- and oxetane-α,ω-telechelic (co)polyolefins have been successfully synthesized by the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins using Grubbs’ second-generation catalyst (<b>G2</b>) in the presence of a bifunctional symmetric alkene epoxide- or oxetane-functionalized chain-transfer agent (CTA). From cyclooctene (COE), <i>trans</i>,<i>trans</i>,<i>cis</i>-1,5,9-cyclododecatriene (CDT), norbornene (NB), and methyl 5-norbornene-2-carboxylate (NB<sup>COOMe</sup>), with bis(oxiran-2-ylmethyl) maleate (CTA <b>1</b>), bis(oxetane-2-ylmethyl) maleate (CTA <b>2</b>), or bis(oxetane-2-ylmethyl) (<i>E</i>)-hex-3-enedioate (CTA <b>3</b>), well-defined α,ω-di(epoxide or oxetane) telechelic PCOEs, P(COE-<i>co</i>-NB or -NB<sup>COOMe</sup>)s, and P(NB-<i>co</i>-CDT)s were isolated under mild operating conditions (40 or 60 °C, 24 h). The oxetane CTA <b>3</b> and the epoxide CTA <b>1</b> were revealed to be significantly more efficient in the CM step than CTA <b>2</b>, which apparently inhibits the reaction. Quantitative dithiocarbonatation (CS<sub>2</sub>/LiBr, 40 °C, THF) of an α,ω-di(epoxide) telechelic P(NB-<i>co</i>-CDT) afforded a convenient approach to the analogous α,ω-bis(dithiocarbonate) telechelic P(NB-<i>co</i>-CDT). The nature of the end-capping function of the epoxide/oxetane/dithiocarbonate telechelic P(NB-<i>co</i>-CDT)s did not impact their thermal signature, as measured by DSC. These copolymers also displayed a low viscosity liquid-like behavior and a shear thinning rheological behavior.
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