チェレーション制御によるアルファ-フルオロケトンのダイアステロ選択的還元
Pramod K Mohanta1, Todd A Davis, Jeremy R Gooch
1Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
Journal of the American Chemical Society
|August 25, 2005
まとめ
テトラクロ化チタン (TiCl4) は,チェレーション制御を介してアルファ-フッ素ケトンからシン-アルファ-フッ素アルコールへのダイアステロ選択的還元を可能にします. 他のチタンのルイス酸は,非ケラ化経路を通じて反ダイアステロエーマー形成を促進する.
科学分野:
- 有機化学 オーガニック・ケミストリー
- ステレオセレクティブ合成
背景:
- アルファ-フッ素ケトンの減少におけるダイアステロ選択性の制御は,キラルアルファ-フッ素アルコール合成に不可欠である.
- チタンベースのルイス酸は,反応経路に影響を与える可能性のために調査されています.
研究 の 目的:
- アルファ-フローロプロピオフェノンのダイアステロ選択的還元のためのTiベースのルイス酸の使用を調査する.
- ケレーション制御が,還元のステレオ化学的結果を制御できるかどうかを判断する.
主な方法:
- アルファ-フルオロプロピオフェノンをTiCl4またはTi(OiPr) 4で処理し,その後LiBH4を減少させる.
- 1H,13C,および19F NMRスペクトロスコピーを用いて反応製品の分析.
主要な成果:
- TiCl4の前処理は主にシンダイアステロエーマーを生成し,ケレーション制御を示した.
- Ti(OiPr) 4の前処理は主に抗ダイアステロエーマーを生成し,非ケラ化経路を示唆した.
- NMR研究では,TiCl4と基板との間のケレーションが確認されました.
結論:
- TiCl4を用いたチェレーション制御は,シン-アルファ-フッ化アルコールの二重選択合成のための効果的な戦略です.
- このアプローチは,他のアルファ-フッ素ケトンに対して一般的であり,幅広い適用性を示しています.
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