螺旋型トリスケリオンモノフォスフィートは,非対称な触媒のリガンドとして作用する
Manfred T Reetz1, Hongchao Guo, Jun-An Ma
1Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany. reetz@mpi-muelheim.mpg.de
Journal of the American Chemical Society
|March 3, 2009
まとめ
螺旋構造を持つ新しいキラル型トリスケリオンフォスフィートリガンドが合成されました. これらの重量のあるリガンドは,非対称な水素化反応で高いエナチオセレクティビティを達成し,触媒の潜在能力を実証しています.
科学分野:
- 有機金属化学 有機金属化学
- アシンメトリック・カタリシス
- リンガンドデザイン リンガンドデザイン
背景:
- キラルリンガンドは,エナチオセレクティブ合成に不可欠である.
- 新しいリガンドアーキテクチャを開発することで,触媒効率と選択性を向上させることができます.
- リガンドの螺旋状構造は,独特のステレオ化学的制御を与えることができます.
研究 の 目的:
- 新種のキラル,C(3) -シンメトリックモノフォスフィートリガンドの合成と特徴づけ.
- ステリック・バルクとコンフォーマーション・リジド性がリガンドの性能に与える影響を調査する.
- Rh触媒による非対称水素化におけるこれらの新型リガンドの有効性を評価する.
主な方法:
- キラルダイオール (BINOL) のモノアシレーションとフォスフォリレーションを伴う2段階の合成.
- X線結晶学とNMRスペクトロスコーピーを用いて特徴づけました.
- ホモアリルアルコールのRh触媒による非対称な水素化におけるリガンドとしての応用.
主要な成果:
- 新規の螺旋状C(3) -対称モノフォスフィートリガンドを成功裏に製造しました.
- アダマンタンから派生した最もステリックに阻害されたリガンドは,プロペラのような幾何学と定義されたヘリシティを持つ硬直なシン形状を採用しました.
- これらの巨大な螺旋状リガンドは,非対称な水素化で高いエナチオ選択性 (79-98% ee) を達成した.
- より硬直な類型は,形状の柔軟性を示し,低エナチオセレクティブ性 (32% ee) をもたらしました.
結論:
- BINOLから派生した大容量で形状的に硬い螺旋状のフォスフィートリガンドは,非対称な水素化に有効です.
- リガンドの適合性柔軟性は,エナチオセレクティブ性に対して負の影響を及ぼします.
- 合成されたリガンドは,キラル触媒の有望な新しいクラスを表しています.
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