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Published January 12, 2010 | Accepted Version
Journal Article Open

Monotelechelic Poly(oxa)norbornenes by Ring-Opening Metathesis Polymerization Using Direct End-Capping and Cross-Metathesis


Two different methodologies for the synthesis of monotelechelic poly(oxa)norbornenes prepared by living ring-opening metathesis polymerization (ROMP) are presented. The first method, termed direct end-capping, is carried out by adding an internal cis-olefin terminating agent (TA) to the reaction mixture immediately after the completion of the living ROMP reaction. The second method relies on cross-metathesis (CM) between a methylene-terminated poly(oxa)norbornene and a cis-olefin TA mediated by the ruthenium olefin metathesis catalyst (H_(2)IMes)(Cl)_(2)Ru(CH-o-OiPrC_(6)H_4) (H_(2)IMes = 1,3-dimesitylimidazolidine-2-ylidene). TAs containing various functional groups, including alcohols, acetates, bromides, α-bromoesters, thioacetates, N-hydroxysuccinimidyl esters, and Boc-amines, as well as fluorescein and biotin groups, were synthesized and tested. The direct end-capping method typically resulted in >90% end-functionalization efficiency, while the CM method was nearly as effective for TAs without polar functional groups or significant steric bulk. End-functionalization efficiency values were determined by ^(1)H NMR spectroscopy.

Additional Information

© 2009 American Chemical Society. Received: August 31, 2009; revised: October 30, 2009. Publication Date (Web): November 16, 2009. We thank Materia for catalyst as well as the National Science Foundation (CHE-0809418), the National Institutes of Health (R01 GM31332), and the National Cancer Institute (5U54 CA119347) for funding. Yan Xia is acknowledged for a generous donation of TA 7. We also thank Paul G. Clark and Dr. David VanderVelde for NMR assistance.

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Accepted Version - nihms-159708.pdf


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August 19, 2023
October 19, 2023