ディメチル硫化物におけるプロリンエナミンの形成経路の再検討:NMRで決定されたレート定数
Michael H Haindl1, Johnny Hioe1, Ruth M Gschwind1
1Institut für Organische Chemie, Universität Regensburg , D-93053 Regensburg, Germany.
Journal of the American Chemical Society
|September 22, 2015
まとめ
この研究はエナミンの形成率を定量化し,DMSOにおける主要な経路としてイミニウム脱プロトネーションを明らかにした. エナミンの形成の動態は,核愛者の強さではなく,実験条件に依存する.
科学分野:
- 器官触媒
- 化学運動学
- 反応メカニズム
背景:
- エナミンの触媒は重要な有機触媒の活性化方式である.
- エナミンの中間物質は極めて重要だが,その形成経路については議論が続いている.
- 提案されたメカニズムは,イミニウムおよび/またはオクサゾリディノンの中間物質を含む.
研究 の 目的:
- エナミン形成の速度定数と速度を実験的に決定する.
- プロリン,水,添加物を含むエナミンの形成率に影響を与える要因を調査する.
- エナミンの形成の主な経路を解明する.
主な方法:
- 1D選択交換スペクトロスコピー (EXSY) の蓄積曲線を使用した.
- 運動分析の初期速度の近似を用いた.
- 実験的な運動データを理論的な計算と組み合わせた.
主要な成果:
- エナミンの形成のための最初の実験的に決定された速度定数を提示した.
- DMSOにおける支配的な経路として,イミニウム中間物の脱プロトン化が特定された.
- プロリンとオクサゾリドニノンのエナミンの形成はゼロオーダーであることが示された.
- 添加物の核好性は,エナミンの形成率ではなく,オクサゾリディノンのイソメリゼーションに影響する.
結論:
- 主要なエナミンの形成経路は条件に依存し,DMSOにおけるイミニウム脱プロトネーションを好む.
- E2メカニズムによるオクサゾリジノンの直接の脱プロトン化は排除されている.
- オキサゾリドニノンの核フィール補助排出は主要な経路ではない.
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