分子間アザ-ワッカー型反応によるインドールのエナンチオセレクティブN-アルキル化
Jamie R Allen1, Ana Bahamonde1, Yukino Furukawa1
1Department of Chemistry , University of Utah , 315 S 1400 E , Salt Lake City , Utah 84112 , United States.
Journal of the American Chemical Society
|May 24, 2019
まとめ
研究者はインドルとアルケノールを用いて新しいエナント選択性アザ=ワッカー反応を開発した. この方法は,ベータ水素を選択的に除去し,エナミンの副産物を避け,ステレオセンターを保存することにより,貴重なキラルアミンを生成します.
科学分野:
- 有機化学
- 非対称な触媒
- 合成方法論
背景:
- ワッカー反応は,炭素−炭素結合を形成する有機合成における基本的な変換である.
- 特に窒素を含有する化合物 (アザ=ワッカー反応) に対して,エナンチオセレクティブの変種を開発することは,依然として重要な課題である.
- 伝統的なアザ-ワッカー反応はしばしば望ましくないエナミン産物につながり,合成経路を複雑にする.
研究 の 目的:
- 新しい分子間選択性アザ=ワッカー反応を 開発する.
- 窒素源としてインドール,結合パートナーとしてアルケノールを利用する.
- 新しく形成されたステレオセンターを保存して,選択的なβ-ヒドリド除去を達成する.
主な方法:
- 分子間結合にパラジウム触媒を用いる.
- インドルと様々なアルケノールを基板として利用する.
- 反応メカニズムの解明のために同位体標識実験を行う.
主要な成果:
- エナチオセレクティブの アザ=ワッカー反応の成功
- 様々な機能群を持つアリルアルコールとホモアリルアルコールとの互換性が実証されている.
- 望ましい製品の形成において高いエナチオ選択性を達成した.
- アルコール部分への選択的β-水素除去が観察され,エナミンの形成が防止された.
結論:
- 開発されたアザ=ワッカー反応は,エナチオメリックに濃縮されたキラルアミンの新しい効率的な経路を提供します.
- この戦略は,排除経路を制御することによって,新たに形成されたステレオセンターを効果的に保存します.
- 同位体ラベリングの研究は,この触媒サイクルに関する洞察を提供するシンアミノパラデーションメカニズムを支持する.
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