Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators
Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators
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DOI：
10.1021/acs.macromol.5b00264
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发表时间：
2015-04-14
期刊：
影响因子：
5.5
通讯作者：
Schrock, Richard R.
中科院分区：
文献类型：
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作者：
Jeong, Hyangsoo;Ng, Victor W. L.;Schrock, Richard R.
使用六种钼和钨亚氨基亚烷基引发剂和两种钨氧代亚烷基引发剂研究了甲基-N-(1-苯乙基)-2-氮杂双环[2.2.1]庚-5-烯-3-羧酸酯（PhEtNNBE；(S)和外消旋）的开环复分解聚合（ROMP）。在我们提出的六种引发剂中，应产生顺式，间规-聚[(S)-PhEtNNBE]，两种钼OHMT亚烷基引发剂，Mo(NR)(CHMe2Ph)(pyr)(OHMT)（R = 1-金刚烷基（Ad）或2,6-Me2C6H3（Ar'）；OHMT = O-2,6-异三叉基(2)C(6)H(3)；pyr = 吡咯烷)，以及两种亚烷基钨引发剂，W(O)(CHMe2Ph)(2,5-二甲基吡咯烷)(PMe2Ph)(OR)（OR = OHMT 或 (R)-OBr(2)Bitet，其中 (R)-Br(2)BitetOH = (R)-3,3'-二溴-2'-(叔丁基二甲基甲硅烷氧基)-5,5',6,6',7,7',8,8'-八氢-1,1'-联萘-2-醇)，产生基本上纯的顺式，间同立构-聚[(S)-PhEtNNBE]。当 (S)-PhEtNNBE 通过 Mo(NAr')(CHCMe2Ph)(OBiphenCF(3))(thf) 或 W(NAr')(CHCMe2Ph)((S)-OBiphenMe) (OBiphenCF(3) = 聚合时，形成基本上纯的顺式，全同立构聚[(S)-PhEtNNBE] 3,3'-二叔丁基-5,5'-双三氟甲基-6,6'-二甲基-1,1'-联苯-2,2'-二醇酯；(S)-OBiphenMe=3,3'-二叔丁基-5,5',6,6'-四甲基-1,1'-联苯-2,2'-二醇酯)。 rac-PhEtNNBE ROMP 的最佳引发剂是 0 ℃ 下的 Mo(NAd)(CHMe2Ph)(pyr)(OHMT)，这导致聚合物偏向（接近 80%）顺式、间同立构结构，并且链中包含交替对映体（顺式、间同、替代聚[(rac)-PhEtNNBE]）。
Ring-opening metathesis polymerization (ROMP) of methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate (PhEtNNBE; (S) and racemic) was investigated employing six molybdenum and tungsten imido alkylidene initiators and two tungsten oxo alkylidene initiators. Of the six initiators that we proposed should yield cis,syndiotactic-poly[(S)-PhEtNNBE], two molybdenum OHMT alkylidene initiators, Mo(NR)(CHMe2Ph)(pyr)(OHMT) (R = 1-adamantyl (Ad) or 2,6-Me2C6H3 (Ar'); OHMT = O-2,6-mesityl(2)C(6)H(3); pyr = pyrrolide), and two tungsten oxo alkylidene initiators, W(O)(CHMe2Ph)(2,5-dimethylpyrrolide)(PMe2Ph)(OR) (OR = OHMT or (R)-OBr(2)Bitet where (R)-Br(2)BitetOH = (R)-3,3'-dibromo-2'-(tert-butyldimethylsilyloxy)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl-2-ol), produced essentially pure cis,syndiotactic-poly[(S)-PhEtNNBE]. Essentially pure cis,isotactic-poly[(S)-PhEtNNBE] was formed when (S)-PhEtNNBE was polymerized by Mo(NAr')(CHCMe2Ph)(OBiphenCF(3))(thf) or W(NAr')(CHCMe2Ph)((S)-OBiphenMe) (OBiphenCF(3) = 3,3'-di-tert-butyl-5,5'-bistrifluoromethyl-6,6'-dimethyl-1,1'-biphenyl-2,2'-diolate; (S)-OBiphenMe = 3,3'-di-tert-butyl-5,5',6,6'-tetramethyl-1,1'-biphenyl-2,2'-diolate). The best initiator for ROMP of rac-PhEtNNBE was Mo(NAd)(CHMe2Ph)(pyr)(OHMT) at 0 degrees C, which led to a polymer that is biased (similar to 80%) toward a cis,syndiotactic structure and that contains alternating enantiomers in the chain (cis,syndio,alt-poly[(rac)-PhEtNNBE]).