An Efficient Ring-Closure Method for Preparing Well-Defined Cyclic Polynorbornenes
An Efficient Ring-Closure Method for Preparing Well-Defined Cyclic Polynorbornenes
复制标题
一种制备结构明确的环状聚降冰片烯的有效闭环方法
DOI：
10.1002/marc.201900598
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发表时间：
2020
影响因子：
4.6
通讯作者：
Ke Zhang
中科院分区：
文献类型：
--
作者：
Minghui Zhang;Ying Wu;Zhengping Liu;Jun Li;Liyan Huang;Ke Zhang
将活性开环易位聚合（ROMP）与自加速双应变促进叠氮-炔环加成（DSPAAC）反应相结合，发展了一种有效的双分子闭环方法，合成了结构明确的环状聚异戊二烯。在该方法中，ROMP被用来合成具有两个叠氮末端的良好定义的线性聚异戊二烯，借助于N-羟基琥珀酰亚胺-酯官能化的Grubbs引发剂，随后对聚合物端基进行改性。然后使用DSPAAC点击反应来闭环线性聚合物前体，并使用对称-二苯并-1，5-环辛-3，7-二炔（DIBOD）作为小连接体制备相应的定义明确的环状聚异戊二烯。自加速DSPAAC闭环反应有助于该方法在相对于线性聚异戊二烯前体摩尔过量的DIBOD小连接体的存在下有效地制备纯环状聚异戊二烯。这是第一个报道，制备明确定义的聚双烯与环状拓扑结构的基础上的环聚合物的闭环策略。
An efficient bimolecular ring-closure method is developed to prepare the well-defined cyclic polynorbornenes by combining the living ring-opening metathesis polymerization (ROMP) with the self-accelerating double strain-promoted azide-alkyne cycloaddition (DSPAAC) reaction. In this method, ROMP is used to synthesize the well-defined linear polynorbornenes with both azide terminals by virtue of a N-hydroxysuccinimide-ester-functionalized Grubbs initiator following the modification of polymer end groups. DSPAAC click reaction is then used to ring-close the linear polymer precursors and prepare the corresponding well-defined cyclic polynorbornenes using the sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DIBOD) as small linkers. The self-accelerating DSPAAC ring-closing reaction facilitates this method to efficiently prepare pure cyclic polynorbornenes in the presence of a molar excess of DIBOD small linkers to the linear polynorbornene precursors. This is the first report to prepare well-defined polynorbornenes with cyclic topology based on the ring-closure strategy for cyclic polymers.