Organocatalysis by hydrogen-bonding: a new approach to controlled/living polymerization of α-amino acid N-carboxyanhydrides
Organocatalysis by hydrogen-bonding: a new approach to controlled/living polymerization of α-amino acid N-carboxyanhydrides
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DOI：
10.1039/c5py00874c
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发表时间：
2015-08
影响因子：
4.6
通讯作者：
Wei Zhao;Y. Gnanou;N. Hadjichristidis
中科院分区：
文献类型：
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作者：
Wei Zhao;Y. Gnanou;N. Hadjichristidis
以氨基醇为引发剂，N，N′-二[3，5-二（三氟甲基）苯基]硫脲（TU-S）为催化剂，采用氢键有机催化法实现了α-氨基酸N-羧酸酐的活性开环聚合.硫脲通过氢键提供NCA单体的同时活化/聚合物链端的可逆失活/叔胺的沉默，从而允许聚合以高度可控的模式进行。例如，通过使用N，N-二甲基乙醇胺（DMEA）作为引发剂，在TU-S存在下，成功地合成了一系列具有不同设计的Mn（3.01 × 104-18.10 × 104）和低PDI值（1.02-1.05）的定义明确的线性多肽。该一般策略还扩展到在TU-S存在下通过使用二氨基醇、三氨基醇或四氨基醇引发剂（甲基二乙醇胺（MDEA）、三乙醇胺（TEA）或N，N，N′，N′-四（2-羟乙基）乙二胺（THEED））合成明确定义的双臂和多臂多肽。
A new method, based on hydrogen-bonding organocatalysis, was developed to achieve living ring-opening polymerization of N-carboxyanhydride of α-amino acids using aminoalcohols as initiators in the presence of N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea (TU-S). The thiourea provides, through hydrogen bonding, simultaneous activation of NCA monomers/reversible deactivation of polymer chain-ends/silencing of the tertiary amine and thus allows the polymerization to proceed in a highly controllable mode. For example, by using N,N-dimethyl ethanolamine (DMEA), as an initiator in the presence of TU-S, a series of well-defined linear polypeptides with differently designed Mns (3.01 × 104–18.10 × 104) and low PDI values (1.02–1.05) were successfully synthesized. This general strategy was also extended to the synthesis of well-defined di- and multi-armed polypeptides by using di-, tri-, or tetra-aminoalcohol initiators (methyldiethanolamine (MDEA), triethanolamine (TEA) or N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (THEED)) in the presence of TU-S.