カテコラートとカテコチオラートRu複合体の反応性と選択性の違い. 立体選択オレフィンメタテシス触媒の設計に関する影響
R Kashif M Khan1, Sebastian Torker, Amir H Hoveyda
1Department of Chemistry, Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467, United States.
Journal of the American Chemical Society
|October 1, 2014
まとめ
ルテニウムカテコチオラート複合体は,オレフィンメタテシスにおいて予想外にも高いZ選択性を達成する. カテコラートとは異なり,それらは構造的整合性を維持し,アルケンの調整ではなく,金属サイクロブタン形成の間にステレオ化学を決定します.
科学分野:
- 有機金属化学 有機金属化学
- カタリシス カタリシス カタリシス
- オーガニック・シンセシス オーガニック・シンセシス
背景:
- オレフィンメタテシスは,有機合成における重要な反応である.
- 高度のステレオ選択性,特にZ選択性を達成することは,依然として課題です.
- ルテニウム複合体は,オレフィンメタテシスの触媒として広く使用されています.
研究 の 目的:
- Ru カテコチオラート複合体における予期せぬZ選択性の起源を解明する.
- オレフィンメタテシスにおけるカテコチオラートとカテコラートRu複合体のメカニズム的な違いを理解する.
- オレフィンメタテシスのZ選択性に関する既存のモデルを改訂する.
主な方法:
- Ru カテコチオラートとカテコラート複合物の合成と特徴付け.
- オレフィンメタテシス反応における触媒活性とZ選択性の評価.
- 密度関数理論 (DFT) の計算により,反応メカニズムを検出する.
主要な成果:
- Ru カテコチオラート複合体は,カテコラート誘導体とは異なり,例外的なZ選択性を示す.
- カテコチオラート複合体は反応条件下で構造的整合性を維持するが,カテコラートは分解する.
- DFT計算では,カタチオラートにおける金属サイクロブタンの形成でステレオ化学が決定され,カタチオラートにおけるアルケンの調整と対照的であることが明らかになった.
結論:
- Ru カテコチオレート複合体の強化されたZ選択性は,それらのユニークなメカニズム経路から生じる.
- 構造的整合性と電子的要因は,ステリックスに加えて,Z-選択性を制御するために重要である.
- この研究は,オレフィンメタテシスにおけるステレオ選択性の現在のモデルを改訂する必要がある.
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