La-BINOL-トリフェニラーシン酸化物複合体を用いたエノンの触媒的非対称エポキシデーション:非対称な触媒の構造的決定
T Nemoto1, T Ohshima, K Yamaguchi
1Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Journal of the American Chemical Society
|July 18, 2001
まとめ
新しいランタン-BINOL-トリフェニラーシン酸化物複合体は,エノンの非対称なエポキシデーションを効率的に触媒化する. この方法は,高収量およびエナチオ選択性を持つエポキシケトンを生成し,触媒機構の洞察を提供します.
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
- オーガニック・シンセシス オーガニック・シンセシス
背景:
- エノンのエポキシデーションは,有機合成における重要な変換である.
- 効率的で選択的な非対称性のあるエポキシデーション触媒の開発は,依然として重要な課題です.
- ランタノイドベースの触媒は,ユニークなルイス酸性および協調性特性を提供します.
研究 の 目的:
- 新しいLa-BINOL-Ph(3) As=O複合体を用いてエノンの触媒的非対称エポキシデーションを記述する.
- 触媒システムの構造と活性種を解明する.
- 反応機構を提案し,ランタンイソプロオキシドの役割を理解する.
主な方法:
- ランタン (III) イソプロポキシド,BINOL,およびトリフェニラーシン酸化物からLa-BINOL-Ph(3) As=O複合体を調製する.
- 触媒の 1-5 mol % を使った様々なエノンの触媒非対称エポキシデーション.
- X線結晶構造分析を用いた構造的特徴化.
主要な成果:
- 触媒系は,ダイエノンとシスエノンを含む様々なエノンを効率的にエポキシド化しました.
- 高収量 (最大99%) と優れたエナチオ選択性 (最大99% ee) が達成されました.
- 活性なLa-BINOL-Ph ((3) As=O複合体の構造が決定され,アルカリ金属のないランタノイド-BINOL複合体の最初のX線解析を代表しました.
結論:
- La-BINOL-Ph ((3) As=O複合体は,非対称なエノンのエポキシデーションのための非常に効果的な触媒である.
- この研究は,非対称増幅におけるヘテロキラル複合体の形成の役割を含む,メカニズム的な洞察を提供します.
- ランタンウムイソプロポキシドは,高いエナンチオセレクティビティを維持しながら反応を加速します.
関連する概念動画
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