ニッケル触媒による還元結合における同時レギオ制御とエナンチオ制御に合わせたNHCリガンド
Hengbin Wang1, Gang Lu2, Grant J Sormunen1
1Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.
Journal of the American Chemical Society
|June 17, 2017
まとめ
新しい種類のエナチオピュアなN-ヘテロサイクリックカルベン (NHC) リガンドは,非常に選択的なニッケル触媒反応を可能にします. これらのリガンドは,アルデヒドとアルキンと結合反応における地域選択性とエナチオ選択性の両方を制御する.
科学分野:
- 有機化学
- カタリシス
- 非対称合成
背景:
- 以前の研究では,ラセミックなN-ヘテロサイクリックカルベン (NHC) リガンドを使用した.
- 純粋なNHCリガンドへのスケーラブルな経路は欠けていた.
- 非常に阻害されたリガンドは,挑戦的な触媒変換に不可欠です.
研究 の 目的:
- エナチオピュアなNHCリガンドのスケーラブルな合成を開発する.
- これらのリガンドを使用して,ニッケル触媒化されたエナチオ選択的還元結合反応を確立する.
- リーゴとエナチオ選択性を制御するリガンドの能力を調査する.
主な方法:
- ブックウォルド・ハートウィッグ N,N-ダイアリレーション リガンド合成
- アルデヒドとアルキンのニッケル触媒によるエナチオ選択的還元結合.
- 方法論をアルデヒドとアレンに拡張する.
- 反応メカニズムとリガンド特性を解明するための計算研究.
主要な成果:
- 異常に阻害されたエナチオピュアなNHCリガンドへのスケーラブルで実践的な経路が達成されました.
- アルデヒドとアルキンのニッケル触媒によるエナチオ選択的還元結合により,高地域性 (> 95: 5) とエナチオ選択性 (94%eまで) のアリルアルコールの誘導体が得られた.
- 方法論はアルデヒドとアレンに拡張され,シリルで保護されたアリルアルコールを生成した.
- リガンド・ステリック・バルクは,以前の方法と比較して補完的な地域化学的結果をもたらした.
- 計算分析により,ステリック阻害,エナチオ選択性,および重要な反応相互作用の起源が説明されました.
結論:
- 開発されたエナチオピュアなNHCリガンドは,ニッケル触媒反応における地域性およびエナチオ選択性を制御するのに非常に有効である.
- これらのリガンドのステリック特性は,挑戦的な基板であっても,高い選択性を達成するための鍵です.
- この研究は,非対称的な合成,特に複雑なアリルアルコールの誘導体を構築するための貴重な新しいツールを提供します.
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