銀で触媒化された非対称なサクラライ・ホソミ・アリレーションによるケトンのアリレーション
Manabu Wadamoto1, Hisashi Yamamoto
1Department of Chemistry, The University of Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|October 20, 2005
まとめ
新しいシルバーフッ化物 (AgF) と (R) -DIFLUORPHOS触媒システムは,ケトンの非対称なサクラライ-ホソミアライレーションを効率的に触媒化する. この方法は,三次性ホモアリルアルコールの高いエナチオセレクティブ性を達成し,エナチオセレクティブクロチレーションを可能にします.
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
- アシンメトリック・シンセシス
背景:
- サクラライ-ホソミ結合は,炭素-炭素結合を形成するための重要な反応です.
- この反応のための効率的でエナチオセレクティブな触媒の開発は,依然として活発な研究分野です.
- 以前の方法は,しばしば特定の基板または厳しい条件を必要とします.
研究 の 目的:
- 単純なケトンの非対称的なサクラライ・ホソミ・アリレーションのための高度なエナンチオセレクティブの触媒系を開発する.
- 溶媒と添加物の触媒性能に対する影響を調査する.
- このシステムの適用を様々なケトン基板とアリレーション反応に探求する.
主な方法:
- シルバーフッ化物 (AgF) と (R) -DIFLUORPHOS.の1:1複合体の形成.
- 溶媒 (THF) とメタノール共触媒を含む反応条件の最適化.
- AgF/(R) -DIFLUORPHOS触媒を,一連の単純なケトンおよび結合ケトンに適用する.
- E-またはZ-クロチルトリメトキシシランを用いたレジオ・ディアステレオ・セレクティブ・およびエナチオ・セレクティブ・クロチレーションの調査.
主要な成果:
- AgF/(R) -DIFLUORPHOS複合体は,単純なケトンのアリレーションに対して,高い触媒活性とエナチオ選択性 (96% eeまで) を示した.
- 溶媒としてのテトラヒドロフーラン (THF) は,反応性を著しく改善しました.
- メタノール (1 equiv) の添加により,触媒の周回量が増加した.
- このシステムは,結合ケトンを持つ1,2-アダクトのみを生成した.
- レジオ・ディアステレオセレクティブ・エナチオセレクティブ・クロチレーションが成功し,E・アリルシランとZ・アリルシランで同様のディアステロエーマー比が観察されました.
結論:
- AgF/(R) -DIFLUORPHOS 1:1複合体は,非対称なサクラライ-ホソミアライレーションのための非常に効果的な触媒である.
- この触媒系は,様々なケトンに広く適用され,優れたエナチオ選択性を持つ三次性ホモアリルアルコールを生成します.
- この発見は,エナチオセレクティブのアリレーション反応におけるラセミックアリシランの有用性を強調し,非対称合成の範囲を広げています.
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