濃度に置換されたアミノ酸によるラック・ラクチドのエナチオセレクティブ・リング開きポリメリゼーション
Ana Sanchez-Sanchez1, Ivan Rivilla2, Maddalen Agirre2
1POLYMAT, University of the Basque Country UPV/EHU , Joxe Mari Korta Center, Avda. Tolosa 72, 20018 Donostia/San Sebastian, Spain.
Journal of the American Chemical Society
|March 9, 2017
まとめ
チラルの有機触媒は,ラックチドのステレオ制御されたリング開きポリメリゼーションを可能にし,高同位性ポリマー濃縮を達成します. 触媒は選択的にl-またはd-ラクチドをポリマー化し,効果的なキラリティの移転を示しています.
科学分野:
- ポリマー化学
- 有機合成
- キャタリシス
背景:
- オーガノカタリシスはポリマー合成に多用途で特異的なアプローチを提供します.
- 有機触媒を用いたステレオ制御ポリメリゼーションは,キラリティ移転の例が限られているため,依然として課題です.
- ラクチドのリング開きポリメリゼーション (ROP) は,生物分解性ポリマー生産に不可欠です.
研究 の 目的:
- ラクチドのROP中にオルガノ触媒からポリマーへのキラリティの移転を実証する.
- 特定のキラルアミノ酸誘導体のステレオ選択的ポリメリゼーション能力を調査する.
- 計算方法を用いたステレオ制御のメカニズム的起源を解明する.
主な方法:
- ラセミック・ラクチド (rac-LA) の有機触媒化リング開封ポリメリゼーション (ROP)
- 1,8-ディアザビサイクロ[5.4.0]アンデック-7-エネ (DBU) を共触媒として使った二酸化アミノ酸派生物 (エンド-6およびエクソ-6) を利用した.
- ポリメリゼーションメカニズムを探求するために,密度関数理論 (DFT) の計算を使用した.
主要な成果:
- 室温でステレオ化学的純度 (Pm) > 0.90の同位性ポリアクチドの合成を達成した.
- 特定の触媒のダイアステレオイソマー (l-LA に対して exo-6,d-LA に対して endo-6) によって,l-ラクチドまたはd-ラクチドの好ましいポリメリゼーションが実証されている.
- DFT計算は,モノメア挿入立体化学を決定する触媒のキラリティの洞察を提供した.
結論:
- チラルのアミノ酸由来有機触媒は,ROP中にチラリティをポリラクチドに効果的に転送することができます.
- 触媒の特異的なダイアステロエーマーがrac-LAポリメリゼーションのステレオ化学的結果を決定する.
- この研究は,高度な材料での潜在的な応用を持つポリラクチドの立体選択合成のための新しい方法を示しています.
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