SmI(2) とH(2) O2を用いたラクトン還元のメカニズム,選択性,合成有用性に関する研究
Dixit Parmar1, Lorna A Duffy, Dhandapani V Sadasivam
1School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.
Journal of the American Chemical Society
|September 22, 2009
まとめ
水で活性化されたサマリウムダイオイド (SmI(2) は,単純なエステルとラクトンを減少させることができます. この新しい SmI(2)-H(2) O システムは,選択的に6基のラクトンを減少させ,ダイアステロ選択的サイクルを可能にします.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
- ランタナイド化学 ランタナイド化学
背景:
- エステルとラクトンは以前,サマリウムダイオイドによる還元に耐性があると考えられていた (SmI(2)).
- 新しい活性化方法は,ランタニド反応剤の合成有用性を拡大するために不可欠です.
研究 の 目的:
- 水で活性化されたSmI(2) を使用してエステルとラクトンの還元を調査する.
- この新しい還元システムの選択性とメカニズム的経路を探求する.
- 生成された中間基質を,その後の合成変換に使用する.
主な方法:
- 制御された量の水 (H2O) でSmI2の活性化.
- 運動研究のためのストップフロースペクトロフォトメトリー.
- 反応メカニズムを解明するための実験的および計算分析.
- ラジカルサイクライゼーション反応により,サイクリックケトンまたはケタルを形成する.
主要な成果:
- SmI(2)-H(2)Oシステムは,単純なアリファティックエステルとラクトンを効果的に減少させます.
- 他のラクトンおよびエステルに比べて,六連鎖ラクトンの減少に対する完全な選択性が観察されました.
- ラジカル中間物質は,サイクル化反応で成功裏に採用され,高ダイアステロ選択性を持つサイクル製品が得られました.
- これらのサイクリングは,エステル-アルケンのラジカルサイクリングの最初の例であり,エステルカルボニルをアシルラジカル相当体として使用しています.
結論:
- 水の活性化により,SmIのエステルおよびラクトンに対する還元力が解き放たれます.
- SmI(2)-H(2)Oシステムは,ラクトン減少のための選択的で強力な方法を提供します.
- この方法論は,エステル-アルケンのラジカルサイクライゼーションによるサイクル化合物のダイアステロ選択合成のための新しい経路を提供します.
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