非対称的環閉オレフィンメタテシスの高度活性キラルルテニウム触媒
Timothy W Funk1, Jacob M Berlin, Robert H Grubbs
1Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Journal of the American Chemical Society
|February 9, 2006
まとめ
新しいキラル型N-ヘテロサイクリックカルベンの触媒は,高エナチオセレクティビティの5〜7基の環を合成するために,効率的な非対称環閉メタテシス (ARCM) を可能にします. ヨウ化ナトリウム添加は,多くの基板の性能を大幅に高めます.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- アシンメトリック・シンセシス
背景:
- オレフィンメタテシスは,C=C結合形成のための強力なツールです.
- チラルのN-ヘテロサイクリックカルベン (NHCs) は,移行金属触媒の新興リガンドである.
- 既知の反応の効率的な非対称的な変種を開発することは,キラル分子合成に不可欠です.
研究 の 目的:
- 新規のキラルモノデンテートN-ヘテロサイクリックカルベン (NHC) リガンドを合成する.
- これらのNHCベースの触媒を非対称環閉メタテシス (ARCM) に適用する.
- 触媒構造と添加物のエナチオ選択性に対する影響を調査する.
主な方法:
- キラルモノデンテートNHCリガンドとその対応する金属触媒の合成.
- これらの触媒を非対称環閉メタテシス反応に用いること.
- イオジウムナトリウムなどの添加物の使用を含む反応条件の最適化.
主要な成果:
- 高反応性キラルNHCベースのオレフィンメタテシス触媒を開発しました.
- 高いエナチオ選択性 (最大92% ee) を5〜7つの環の形成で達成した.
- いくつかの基板に対するエナチオセレクティブ性に対するヨウ素酸ナトリウムの有意な陽性効果を示した.
- NaIのない低負荷 (<または=1 mol %) で有効な触媒 (5a) を特定しました.
結論:
- チラルのNHC触媒は,ARCMに対して有効であり,アチラルの同類の反応性に匹敵する.
- ヨド酸ナトリウムは,多くの基板のエナチオ選択性を高める上で重要な役割を果たしています.
- ステリック改変を含む触媒の設計は,ARCMの性能に影響します.
- ヨウ素酸ナトリウム効果とARCM経路に関するメカニズム的な洞察が議論されました.
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