posted on 2014-08-06, 00:00authored byWilliam
P. Forrest, Jonathan G. Weis, Jeremy M. John, Jonathan C. Axtell, Jeffrey
H. Simpson, Timothy M. Swager, Richard R. Schrock
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.