ステレオ選択的触媒は,アキラル鉄触媒の前駆体によるインシチュア脱対称化によって達成される
Cesar M Manna1, Aman Kaur1, Lauren M Yablon1
1Eugene F. Merkert Chemistry Center, Department of Chemistry, Boston College , 2609 Beacon Street, Chestnut Hill, Massachusetts 02467, United States.
Journal of the American Chemical Society
|October 29, 2015
まとめ
新しい鉄触媒は,キラル成分なしで乳酸のステレオ選択的ポリメリゼーションを可能にします. この突破はポリマー構造を制御するためにアキラル添加物を使用し,ステレオレギュラーポリマーへのより単純な経路を提供します.
科学分野:
- ポリマー化学
- 有機金属化学
- カタリシス
背景:
- ステレオセレクティブポリメリゼーションは,特定の性質を持つポリマーを作成するために不可欠です.
- 伝統的な方法は,しばしば複雑な,前合成のキラル触媒またはリガンドを必要とします.
- よりシンプルで効率的なステレオ選択型触媒システムの開発は,依然として重要な課題です.
研究 の 目的:
- ラクティドの新型ステレオ選択的ポリメリゼーション方法を開発する.
- ポリマー立体化学を制御するための鉄ベースの触媒を調査する.
- キラルの補助装置がない場合のステレオ制御のメカニズムを解明する.
主な方法:
- アキラルシラノール添加物を含んだ鉄基の触媒を用いてラクチドをポリマー化した.
- ポリマーの微細構造を特徴付けるために,光譜分析 (例えば,NMR) を採用した.
- 反応運動を研究し,モデル複合体を使用した.
- 密度関数理論 (DFT) の計算を行い,機械論的提案を支援した.
主要な成果:
- アキラル鉄触媒とアキラルシラノール添加物を用いて乳酸のステレオ選択的ポリメリゼーションを達成した.
- ステレオ制御が示された光学データは,鎖の末端ではなく,エナチオモルフな触媒部位から発生した.
- 脱対称化によるステレオゲンな鉄の中間物質の in situ 形成を特定した.
- 実験データと計算データで裏付けられたメカニズムを提案した.
結論:
- アキラル成分を用いたステレオ選択的触媒の新しいアプローチを示した.
- 制御された乳酸ポリメリゼーションのための鉄触媒システムを確立した.
- 現地でのステレオジェニック金属センター形成とステレオ制御に関する機械的洞察を提供した.
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