title: Stereospecific ring-opening metathesis polymerization of norbornadienes employing tungsten oxo alkylidene initiators.
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.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: William P
authors.initials: WP
authors.lastname: Forrest
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Weis
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: John
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Axtell
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Simpson
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Swager
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schrock