Stereospecific ring-opening metathesis polymerization of norbornadienes employing tungsten oxo alkylidene initiators

William P Forrest; Jonathan G Weis; Jeremy M John; Jonathan C Axtell; Jeffrey H Simpson; Timothy M Swager; Richard R Schrock

doi:10.1021/ja506446n

Stereospecific ring-opening metathesis polymerization of norbornadienes employing tungsten oxo alkylidene initiators

J Am Chem Soc. 2014 Aug 6;136(31):10910-3. doi: 10.1021/ja506446n. Epub 2014 Jul 22.

Authors

William P Forrest¹, Jonathan G Weis, Jeremy M John, Jonathan C Axtell, Jeffrey H Simpson, Timothy M Swager, Richard R Schrock

Affiliation

¹ Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.

PMID: 25036528
DOI: 10.1021/ja506446n

Abstract

We report here the polymerization of several 7-isopropylidene-2,3-disubstituted norbornadienes, 7-oxa-2,3-dicarboalkoxynorbornadienes, and 11-oxa-benzonorbornadienes with a single tungsten oxo alkylidene catalyst, W(O)(CH-t-Bu)(OHMT)(Me2Pyr) (OHMT = 2,6-dimesitylphenoxide; Me2Pyr = 2,5-dimethylpyrrolide) to give cis, stereoregular polymers. The tacticities of the menthyl ester derivatives of two polymers were determined for two types. For poly(7-isopropylidene-2,3-dicarbomenthoxynorbornadiene) the structure was shown to be cis,isotactic, while for poly(7-oxa-2,3-dicarbomenthoxynorbornadiene) the structure was shown to be cis,syndiotactic. A bis-trifluoromethyl-7-isopropylidene norbornadiene was not polymerized stereoregularly with W(O)(CHCMe2Ph)(Me2Pyr)(OHMT) alone, but a cis, stereoregular polymer was formed in the presence of 1 equiv of B(C6F5)3.