ヒドロキシクロペンタディエニルルテニウム水化物によるイミン還元の立体化学
Charles P Casey1, Galina A Bikzhanova, Ilia A Guzei
1Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA. casey@chem.wisc.edu
Journal of the American Chemical Society
|February 16, 2006
まとめ
ルテニウム複合体からN-アリルイミンへの水素の移転は,主にトランスステレオスペシフィックであり,アミン複合体を形成します. しかし,N-アルキルイミンへの移行は,より速い可逆性のためにステレオランダムです.
科学分野:
- 有機金属化学 有機金属化学
- ステレオ化学 ステレオ化学
- 反応メカニズム 反応メカニズム
背景:
- ルテニウム複合体は,有機合成における汎用的な触媒である.
- 水素転送機構の理解は,効率的な触媒プロセスを開発するために不可欠です.
- 水素移転のステレオ化学的結果は,基板構造によって影響を受けます.
研究 の 目的:
- 特定のルテニウム複合体から異なるイミン基板への水素移転の立体化学を調査する.
- これらの反応におけるステレオ特異性を支配するメカニズム的経路を解明する.
主な方法:
- ルテニウムデウテリド複合体の合成 [2,5-Ph(2)-3,4-Tol(2)(eta(5)-C(4) COD) ]Ru(CO) ((2) D.
- ルテニウム複合体のN-アリルとN-アルキルイミンとの反応.
- 結果となるアミン複合体のステレオ化学的結果の分析.
主要な成果:
- N-アリルイミンへの水素移転は,高いトランスステレオ特異性で進行した.
- 提案されたメカニズムは,座標的に不飽和のルテニウム中間物質と急速なアミン座標の形成を伴う.
- N-アルキルイミンへの水素移転は,ステレオランダムな産物をもたらし,アミン協調よりも速い可逆性を示唆しています.
結論:
- ルテニウム触媒による水素移転の立体化学的結果は,イミン基板に非常に依存しています.
- アミン産物の迅速な調整は,N-アリルイミンとのステレオ特異性を維持する鍵です.
- 水素移転の可逆性は,N-アルキルイミンとのステレオ選択性を決定する上で重要な役割を果たします.
関連する概念動画
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Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
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Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...