ニトロンとアクロレインの非対称1,3-二極サイクロアディション反応は,キラルルイス酸としてビスチタニウム触媒を用いて行われる
Taichi Kano1, Takuya Hashimoto, Keiji Maruoka
1Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Journal of the American Chemical Society
|August 25, 2005
まとめ
キラル型ビスチタニウム ((IV) オキシド触媒は,非対称の1,3-二極サイクロアディション反応を効率的に促進する. この方法は,高いエナチオセレクティブ性を持つイソクサゾリジンを生成し,ステレオセレクティブ合成におけるその有用性を実証しています.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- ステレオセレクティブ合成
背景:
- 非対称な1,3-二極サイクロアディション反応は,キラル分子合成に不可欠である.
- これらの反応のための効率的で選択的な触媒の開発は,有機化学の主要な課題です.
研究 の 目的:
- 1,3-二極サイクロアディション反応の非対称性において,ムオクソ型キラルビスチタニウムオキシド触媒 (S,S) -1の有効性を調査する.
- ニトロンとアクロレインからイソクサゾリジンの合成において,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:
- チラルのビスチタニウム ((IV) オキシード触媒, (S,S) -1,を使用しました.
- 様々なニトロン (2) とアクロレインの間の非対称的1,3-二極サイクロアディション反応を使用した.
- ディクロロメタンで -40°Cで反応を行った.
主要な成果:
- ビス-チタニウム ((IV) オキシド触媒 (S,S) -1) は,サイクル添加反応を効果的に媒介した.
- 結果となるイソクサゾリジンには,高いから優れたエナチオセレクティビティが達成された.
- 特定の例では,ニトロン2 (R = t-Bu) とアクロレインを用いたエンドサイクルロードダクトの97%のエナティオメア過剰 (ee) が,10mol %の触媒負荷で示された.
結論:
- ムオクソ型キラル bis-Ti (IV) オキシード (S,S) -1は,非対称的1,3-二極サイクロアディションの非常に効果的な触媒である.
- この触媒系は,エナチオメリックに濃縮されたイソキサゾリジンへの貴重な経路を提供する.
- この方法論は,複雑な有機分子をステレオ選択的に合成する大きな可能性を示しています.
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