Synthesis of ABA Triblock Copolymers via Acyclic Diene Metathesis Polymerization and Living Polymerization of α-Amino Acid−N-Carboxyanhydrides

Abstract

The synthesis of poly(γ-benzyl-L-glutamate)-b-polyoctenamer-b-poly(γ-benzyl-L-glutamate) (13) and poly(γ-benzyl-L-glutamate)-b-polyethylene-b-poly(γ-benzyl-L-glutamate) (14) triblock copolymers is described. R,ω-Bisamino-terminated polyoctenamer (5) was used to prepare a difunctional macroinitiator (12) used for the living polymerization of γ-benzyl-L-glutamic acid-N-carboxyanhydride (Glu-NCA) to form the triblock copolymers. 5 was synthesized by acyclic diene metathesis polymerization of 1,9-decadiene (1) in the presence of 11-phthalimido-1-undecene (2) and Grubbs' metathesis catalyst, RuCl2(dCHPh)-( PCy3)2 (3). Deprotection of the resulting phthalimide end-functionalized polymers (4) was performed, leading to difunctional 5 with number-average functionalities close to two. These methods allow the controlled preparation of polypeptide/(hydrocarbon polymer) block architectures with good control over the chain lengths of both domains and without formation of homopolypeptide contaminants.

Polypeptide und 100 Jahre Chemie der α‐Aminosäure‐N‐carboxyanhydride

“…Die Telechele der Struktur 29 wurden in Ni-Komplexe (30) umgewandelt, die zur Initiierung von NCA-Polymerisationen befähigt waren. [112] Abschließend soll noch eine neue Publikation einer anderen Arbeitsgruppe erwähnt werden, [114] …”

“…Weitere Triblockcopolymere mit einem hydrophoben Segment wurden mithilfe von NH 2 -terminiertem telechelem Polybutadien hergestellt, das vorwiegend aus 1,4-trans-Einheiten bestand. Dieses polymere Diamin wurde als Initiator für die ROP von g-Bzl-l-Glu-NCA verwendet, [162,163] [112] Zahlreiche ABA-Triblockcopolymere [164][165][166][167][168] sowie Pentablock-, [113] Hexablock- [169] und Multiblockcopolymere [170,171] wurden ausgehend von difunktionellen PEO-Blocks aufgebaut. Wie in den Formeln 61-63 exemplarisch illustriert, wiesen die PEO-Segmente zwei Aminoendgruppen auf, die als Initiatoren für NCAs wirkten, oder sie hatten Carboxyendgruppen, die zur Kettenverlängerung dienten (63).…”

Useful synthetic method of polypeptides with well‐defined structure by polymerization of activated urethane derivatives of α‐amino acids

“…Polypeptides have received great attention as promising components for new design of various macromolecular architectures, [1][2][3][4][5] because of its intriguing feature such as a-helix and b-sheet. For polypeptide synthesis, various synthetic strategies have been developed.…”

Revolutionary phosgene‐free synthesis of α‐amino acid N‐carboxyanhydrides using diphenyl carbonate based on activation of α‐amino acids by converting into imidazolium salts

“…[1][2][3][4][5][6][7][8][9][10] Currently, NCAs are synthesized conveniently by treatment of a-amino acids with phosgene, phosgene dimer, or phosgene trimer. [11][12][13][14] These carbonyl sources are highly reactive, but at the same time, they are lethally toxic so that their uses are limited to only smallscale operations.…”

“…Another method established eariler than the phosgene method is ''Leuch's method,'' which is based on the cyclization of N-alkoxycarbonyl amino acid chloride. 15 This method allows a straightforward access to NCA; however, its application to industrial production of NCA would be difficult, because of the requirement of the use of corrosive halogenating reagents (such as PBr 3 , PCl 5 , and SOCl 2 ) and the formation of carcinogenic alkyl halides as a result of the cyclization.…”