Highly stereoselective ruthenium-catalyzed ring-opening metathesis polymerization of 2,3-difunctionalized norbornadienes and their 7-oxa analogues
Highly stereoselective ruthenium-catalyzed ring-opening metathesis polymerization of 2,3-difunctionalized norbornadienes and their 7-oxa analogues
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DOI：
10.1021/ma9812783
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发表时间：
1999-04-06
期刊：
影响因子：
5.5
通讯作者：
Noels, AF
中科院分区：
文献类型：
--
作者：
Delaude, L;Demonceau, A;Noels, AF
在三甲基硅基重氮甲烷(TMSD)存在下，[RuCl(2)(对伞花烃)](2)催化2，3-二官能化降冰片二烯及其7-氧杂类似物的开环歧化聚合(ROMP)，得到了高反式、高策略的聚合物。提出了一个涉及芳烃损失、卡宾生成和单体络合的初步机理。以2，3-二甲氧基降冰片二烯的反应为例，考察了各种实验参数(反应时间和温度、溶剂和催化剂的性质以及TMSD引发条件)对反应的影响。在各种条件下得到了一种全反式、高转化率(>；79%)的聚合物。值得注意的是，三环己基膦的加入对聚合产率和立体选择性有不利影响。该方法成功地应用于其他各种2，3-二羧烷氧基降冰片二烯、苯基冰片二烯和它们的7-氧杂类似物。对于双酯单体，烷基取代基尺寸的增加导致聚合物反式含量和规整度的降低。由于Ru催化剂的易得性和显著的耐氧性和耐水性，反应非常容易建立和进行。
The ring-opening metathesis polymerization (ROMP) of 2,3-difunctionalized norbornadienes and their 7-oxa analogues catalyzed by [RuCl(2)(p-cymene)](2) in the presence of trimethylsilyldiazomethane (TMSD) yields high-trans, highly tactic polymers. A tentative mechanism involving arene loss, carbene formation, and monomer chelation is presented. The ROMP of 2,3-dicarbomethoxynorbornadiene served as a test reaction to investigate the influence of the various experimental parameters (reaction time and temperature, nature of the solvent and catalyst, and TMSD initiation conditions). An all-trans, highly tactic (>79%) polymer was obtained under a wide variety of conditions. Strikingly, the addition of tricyclohexylphosphine had a detrimental influence on the polymerization yield and stereoselectivity. The procedure was successfully applied to various other 2,3-dicarboalkoxynorbornadienes, benzonorbornadiene, and their 7-oxa analogues. In the case of the diester monomers, an increase in the alkyl substituent size led to a decrease of the polymer trans content and tacticity. Because of the ruthenium catalyst's ready availability and marked resistance to oxygen and water, reactions were very easy to set up and to carry out.