Synthesis and End Group Structure of 2-Deoxydextrans Prepared via the Cationic Ring-Opening Polymerization of an Anhydro Sugar
Synthesis and End Group Structure of 2-Deoxydextrans Prepared via the Cationic Ring-Opening Polymerization of an Anhydro Sugar
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脱水糖阳离子开环聚合2-脱氧葡聚糖的合成及端基结构
DOI：
10.1021/ma012033k
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
T. Patten
中科院分区：
文献类型：
--
作者：
Yu;A. Franz;Chris L. Newbury;C. Lebrilla;T. Patten
以1-氯乙基异丁基醚或异丙基氯为引发剂，ZNi2为活化剂，聚合1，6-Anhydro-3，4-di-O-benzyl-2-deoxy-β-D-glucose。所得聚合物主要含有α-(1，6)键，且分子量分布较窄(≤1.25)。聚合反应动力学与单体浓度呈一级反应关系。在这些聚合温度下，有证据表明链转移缓慢，尽管大多数聚合物链含有引发剂片段。聚合物的质谱图表明，聚合物链端的引发剂片段是一个异丁基，可能是由于单体对引发阳离子中异丁基的亚甲基单元进行亲核攻击而失去乙醛，而不是对sp2-亚甲基碳的亲核攻击。环状低聚物也存在于聚合物样品中，可能来自两个过程：HCl引发或背后攻击反应。
1,6-Anhydro-3,4-di-O-benzyl-2-deoxy-β-D-glucose was polymerized using 1-chloroethyl isobutyl ether or cumyl chloride as initiator and ZnI 2 as activator. The resulting polymer contained predominantly α-(1,6) linkages, and the molecular weight distributions were narrow (≤1.25). The kinetics of polymerization was first-order with respect to monomer concentration. There was evidence of slow chain transfer at these polymerization temperatures, although the majority of polymer chains contained the initiator fragment. Mass spectra of the polymer revealed that the initiator fragment at the polymer chain end was an isobutyl group, presumably arising from nucleophilic attack of monomer on the methylene unit of the isobutyl group in the initiating cation with loss of acetaldehyde as opposed to attack at the sp 2 -methylene carbon. Cyclic oligomers were present in the polymer sample as well and could have arisen from two processes: HCl initiation or a backbiting reaction.