Helix-Sense-Selective and Enantiomer-Selective Living Polymerization of Phenyl Isocyanide Induced by Reusable Chiral Lactide Using Achiral Palladium Initiator

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• 作者：Jia-Li Chen ; Li Yang ; Qian Wang ; Zhi-Qiang Jiang ; Na Liu ; Jun Yin ; Yunsheng Ding ; Zong-Quan Wu
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：November 10, 2015
• 年：2015
• 卷：48
• 期：21
• 页码：7737-7746
• 全文大小：649K
• ISSN：1520-5835

文摘

Polymerization of phenyl isocyanide using achiral Pd(II) initiator with the presence of chiral l- or d-lactide (l-LA or d-LA) as additive was found to proceed in helix-sense-selective manner. The polymerization of achiral phenyl isocyanide, 4-isocyanobenzoyl-2-aminoisobutyric acid decyl ester (1) by this method produced optically active helical poly-1_m(L), whose chirality was solely come from the helical conformation without containing of any other chiral atoms. The added chiral LA can be facilely recovered and reused in the helix-sense-selective polymerizations without significantly loss of its chiral induction, and the chiral economy of the polymerization is high. When enantiomerically pure phenyl isocyanide bearing an R- or S-alanine pendent with a long n-decyl chain (1r or 1s) were polymerized by this method, the polymerization was found to proceed in a highly enantiomer-selective manner with one of the enantiomers preferentially polymerized over the antipode by a factor of 3.6. Single-handed helical polyisocyanides can be achieved when the chirality of the monomer was appropriately matched with the added LA.