有机催化的氨基酸来源单体的开环聚合  

Organocatalytic Ring-opening Polymerization of Amino Acid-based Monomers

作　　者：和文婧 陶友华[1] Wen-jing He;You-hua Tao(Key Laboratory of Polymer Ecomaterials,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022)

机构地区：[1]中国科学院长春应用化学研究所,中国科学院生态环境高分子材料重点实验室,长春130022

出　　处：《高分子学报》2020年第10期1083-1091,I0002,共10页Acta Polymerica Sinica

摘　　要：以具有多个官能基团的氨基酸单体为原料,通过发展新的合成方法制备高分子,不仅可以大幅降低合成高分子工业对石油的依赖程度,还能获得具有丰富功能侧基的聚氨基酸、聚酯等功能高分子材料,已经成为当今世界上高分子合成化学的前沿和热点领域.开环聚合是氨基酸单体聚合的核心,但是氨基酸开环聚合领域目前仍存在诸多瓶颈科学问题:(1)缺乏合适的环状单体用以获得一些重要的生物大分子如聚(ε-赖氨酸)、聚(γ-谷氨酸)等;(2)氨基酸来源环状单体,在开环聚合时容易消旋,导致聚合物立构规整度降低.这些都严重制约着氨基酸聚合物的发展和应用.针对这些挑战,近年来我们课题组从高效高选择性的有机催化剂的角度出发,发展了有机催化的七元环状赖氨酸单体的开环聚合,突破了抗菌性聚(ε-赖氨酸)只能采用生物法合成的局限,并发展了有机弱碱催化的氨基酸来源O-羧基环内酸酐(OCA)单体的开环聚合,有效地抑制了单体在开环聚合过程中的消旋现象.我们相信,进一步发展高效高选择性的有机催化体系是未来氨基酸单体开环聚合研究的重中之重.Poly(amino acid)s are important biomimetic materials due to their unique biocompatibility, and potential application in gene transfection, drug delivery, and prevention of viral infections. For example, poly(ε-lysine) is an uncommon cationic homopolymer produced by the fermentation process. Although poly(amino acid)s are developing rapidly, the simple synthesis of poly(amino acid)s, especially functional poly(amino acid)s such as poly(ε-lysine) still remains a challenge. Fortunately, we have seen a drastic rising trend in the area of organocatalytic ring-opening polymerization(ROP) of amino acid-based monomers for polymers. Our lab succeeded in developing a superbase t-BuP4-catalyzed ROP of cyclic lysine monomers, affording high molecular weight poly(ε-lysine) bearing pendant protected amino groups with high monomer conversion(up to 95%). The organocatalytic polymerization could proceed at low reaction temperature(e.g., 60 ℃) compatible with readily removable protecting groups, providing a sustainable and new methodology toward facile preparation of poly(ε-lysine). Moreover, we developed an effective bifunctional single molecule organocatalysis for selective ROP of amino acid-based O-carboxyanhydride(OCA) monomers without epimerization. The close vicinity of both activating groups in the same molecule engender an amplified synergetic effect and thus allows for the use of mild bases, thereby leading to minimal epimerization for polymerization. In the following article, recent examples of the organocatalysis for amino acid-based polymers synthesis are presented, as will their suitability for stereoregular isotactic polymers. The advantages and limitations of the organocatalytic ROP of amino acid-based monomers are discussed, which is important for the simple and general synthesis of amino acid-based polymers.

关 键 词：有机催化 氨基酸 聚(ε-赖氨酸) 开环聚合 立构规整 

分 类 号：TQ316.341[化学工程—高聚物工业]