N-Boc-イミダゾールとオクサゾールを触媒的に非対称に水素化する
Ryoichi Kuwano1, Nao Kameyama, Ryuhei Ikeda
1Department of Chemistry, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan. rkuwano@chem.kyushu-univ.jp
Journal of the American Chemical Society
|April 29, 2011
まとめ
研究者らは,新しいルテニウム触媒を用いて,置換されたイミダゾールとオクサゾールをキラルイミダゾリンとオクサゾリンに高度にエナチオセレクティブに水素化することを達成した. この画期的な発見により,5基のヘテロサイクルのアロマティックリングの触媒的非対称的還元が可能になった.
科学分野:
- 有機化学 オーガニック・ケミストリー
- アシンメトリック・カタリシス
- ヘテロサイクル化学 ヘテロサイクル化学
背景:
- チラルのヘテロサイクリック化合物は,医薬品と材料科学における重要な構成要素です.
- エナティオメリックに純粋なイミダゾリンとオクサゾリンを合成するための効率的な触媒的方法は非常に求められています.
- 以前の5基のアロマティックヘテロサイクルを減少させる方法は,しばしばステレオ選択性が欠けているか,厳しい条件を必要とする.
研究 の 目的:
- 置換されたイミダゾールとオクサゾールの非対称な水素化のための新しい触媒システムを開発する.
- 窒素と酸素のヘテロ原子を含む5つ組の芳香環の還元で高いエナチオセレクティブ性を達成するために.
- キラルイミダゾリンとオクサゾリンを合成するための新しい方法の確立.
主な方法:
- キラルルテニウム触媒を用いた代替イミダゾールとオクサゾールの水素化.
- 触媒は,Ru (η) 3 (メタリル) 2 (コッド) とトランスケレーティングキラルビスホスフィンのリガンドであるPhTRAPからインシットで生成された.
- キラルクロマトグラフィを用いたエナティオメア過剰 (ee) の分析.
主要な成果:
- イミダゾールとオクサゾールの相応のキラルイミダゾリンとオクサゾリンへの水素化の成功.
- 製品で最大99%のエナティオメリック過剰 (ee) を達成しました.
- 複数のヘテロ原子を持つ5つあるアロマティックリングの最初の成功した触媒的非対称的還元を実証した.
結論:
- 開発されたルテニウム-PhTRAP触媒システムは,非対称な水素化のための非常に効果的な経路を提供します.
- この方法は,エナチオメリックに濃縮されたキラルイミダゾリンとオクサゾリンの合成において,著しい進歩をもたらします.
- 挑戦的なヘテロサイクルアロマティック基板の触媒的非対称性還元における画期的な進歩を表しています.
関連する概念動画
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One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
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