非対称的Ni触媒付き結合アリレーション 活性化されたエノンの結合アリレーション
Joshua D Sieber1, James P Morken
1Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Journal of the American Chemical Society
|March 15, 2008
まとめ
この研究では,アリルボロン酸ピナコールエステルを使用したダイアルキリデンケトンのエナチオセレクティブアリレーションのためのニッケル触媒反応を詳細に説明しています. 高レベルのエナチオ選択性が達成され,複合基板におけるベンジリデンの部位を好みました.
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
- 合成有機化学 合成有機化学について
背景:
- ダイアルキリデンケトンは,多用途の合成中間物質です.
- エナチオセレクティブ・アリレーションは,キラル分子の合成に不可欠である.
- これらの変換のための効率的な触媒システムの開発は,依然として課題です.
研究 の 目的:
- ディアルキリデンケトンにアリルボロン酸ピナコールエステル (allylB(pin)) をニッケル触媒でエナチオセレクティブで添加する新型エナチオセレクティブを開発する.
- 反応のメカニズムと基質の範囲を調査する.
- アリレーション過程で高いエナンチオセレクティビティを達成するために.
主な方法:
- アリルボロン酸ピナコールエステルを使用したニッケル触媒反応.
- 非対称なダイアキリデネケトンを基板として使用する.
- チラルリガンド14は,エナチオセレクティビティを誘発するために使用されました.
主要な成果:
- この反応は,様々なダイアキリデンケトンで高い効果を示した.
- ベンジリデンの部位でのアリレーションの好みは非対称な基板で観察されました.
- キラルリガンド14で91~94%eEのエナチオ選択性が得られた.
- 提案されたメカニズムは,不飽和のpi-アリル複合体の形成を伴うもので,その後に還元性除去が続く.
結論:
- ダイアキリデンケトンの非常に効果的なニッケル触媒化されたエナチオセレクティブアリレーションが確立されています.
- この方法は,優れたエンアンチオコントロールを持つキラル製品へのアクセスを提供します.
- 反応メカニズムは,ニッケル媒介の触媒サイクルに関する洞察を提供します.
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