C2対称ビス ((オキサゾリナト) ランタニド触媒は,エナチオセレクティブの分子内ヒドロアミネーション/サイクリングのための
Sukwon Hong1, Shun Tian, Matthew V Metz
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
Journal of the American Chemical Society
|December 4, 2003
まとめ
新しいキラルC(2) -対称 bis(oxazolinato) ランタニド複合体は,エナチオセレクティブの分子内ヒドロアミネーション/サイクリング反応を効率的に触媒化する. これらの前触媒は,in situで生成され,特により大きなランタニドイオンでは,高いターンオーバー周波数とエナチオセレクティビティを示します.
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
- アシンメトリック・シンセシス
背景:
- チラルランタニド複合体は,非対称な変換の触媒としてますます探索されています.
- 効率的なエナチオセレクティブの分子内ヒドロアミネーション/サイクリング反応は,窒素を含むヘテロサイクルを合成するために不可欠です.
- これらの反応のための新種の前触媒の開発は,依然として活発な研究分野です.
研究 の 目的:
- エナチオセレクティブの分子内ヒドロアミネーション/サイクリングのための前触媒として,新しいC(2) -対称ビス ((oxazolinato) ランタニド複合体を開発および評価する.
- リンガンド構造とランタニドイオン半径が触媒活性と選択性に及ぼす影響を調査する.
- 触媒プロセスに関与するメカニズムと活性種を解明する.
主な方法:
- C(2) -対称 bis(oxazolinato) ランタニド複合体の合成と特徴付け.
- ランタニド金属前駆体とビス ((オクサゾリン) リガンドからプレカタライストのインシット生成.
- 理想的な触媒性能のために,様々なbis ((オクサゾリン) リガンドとランタニド金属のスクリーニング.
- X線結晶学により,前触媒種の構造を決定する.
- 反応メカニズムを理解するための運動学的研究.
主要な成果:
- 開発された前触媒は,アミノアルケンとアミノディエンのエナチオセレクティブの分子内ヒドロアミネーション/サイクリングを効率的に触媒化する.
- イオン半径が大きいランタニド (例えば,La) は,より高い回転周波数とエナチオ選択性を示した.
- リガンド構造,特にアリルステレオ誘導群とオクサゾリン環の5位での置換は,触媒効率に大きく影響する.
- 最適化された前触媒は67%eまでのエナティオメール過剰を達成し,既存のキラルオルガノランタノセンの触媒と同等またはそれ以上であった.
- 運動学的研究は,モノメリック活性種と,オレフィン挿入を伴うメカニズムと,その後にプロトノリシスを伴うメカニズムを示す.
結論:
- C(2) -対称 bis(oxazolinato) ランタニド複合体は,エナチオセレクティブの分子内ヒドロアミネーション/サイクリングの効果的な前触媒である.
- 触媒の性能は,リガンドの設計とランタニド金属の選択によって調整できます.
- これらのシステムは,キラル窒素を含む化合物の合成のための既存の触媒の有望な代替案を提供します.
さらに関連する動画
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