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アルケニルフォスファートによるヘック反応に関する研究:1,2移動は制御できるのか? 適用範囲と制限
Jean-Philippe Ebran1, Anders L Hansen, Thomas M Gøgsig
1The Center for Insoluble Protein Structures inSPIN, Department of Chemistry, the Interdisciplinary Nanoscience Center, University of Aarhus, Langelandsgade 140, 8000 Aarhus, Denmark.
Journal of the American Chemical Society
|May 4, 2007
まとめ
この研究は,ヘック結合反応のための新しい触媒システムを導入し,単純なビニルリン酸塩およびアルケンからダイエン産物の合成を可能にします. ブッチャワルドのダイアルキルビアリルフォスフィンのリガンドであるX-Phosは,不要な中間移動を抑制しながら,ビニル代替を効果的に促進します.
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
- 合成方法論 合成方法論
背景:
- ヘック結合反応は,炭素-炭素結合形成のための強力なツールです.
- 非活性化基板の結合のための効率的な触媒システムの開発は,依然として課題です.
- 地域選択性を制御し,1,2-移住のような副作用を防ぐことは,合成ユーティリティにとって極めて重要です.
研究 の 目的:
- 非活性化されたビニルリン酸塩と電子欠乏アルケンのヘック結合のための新しい触媒システムの開発.
- この変換におけるリガンドとして,ブックワルドのダイアルキルビアリルフォスフィン (例えば,X-Phos) の使用を調査する.
- アルケニルパラジウム中間物質の1,2移動を調査し,制御する.
主な方法:
- シクロオクタディエン (PdCl2 ((COD)) とバッハワルドのダイアルキルビアリルフォスフィン (X-Phos) と複合したパラジウム (II) クロライドを触媒システムとして使用した.
- ビニル代用を促進する添加物としてリチウム塩化物を使用しています.
- ビニルリン酸塩基基板にC1置換物の影響を調査し,異体化と移動を制御しました.
- アリルハリドによる競争実験を行い,触媒の選択性を評価した.
主要な成果:
- X-Phosリガンドは,電子欠乏アルケンの様々なアルケニルリン酸塩のヘック結合を効果的に促進しました.
- 塩化リチウムを添加すると,アルケニルパラジウム (II) の中間物質の1,2移動が抑制された.
- 1,2-移動の程度はC1-置換物に依存し,C1-アルキル四次炭素が最適な結果をもたらした.
- ビニルリン酸塩に対するアリルハリドとの選択的ヘック結合は,細心のリガンド選択によって達成された (X-Phos vs. P(t-Bu) 3).
結論:
- 非活性化ビニルリン酸塩のヘック結合のための新しい効率的な触媒システムが開発されました.
- フォスフィンリガンド (X-PhosまたはP(t-Bu) 3) の選択により,移住したヘック製品または移住していないヘック製品の優先合成が可能になります.
- 触媒システムは,ビニルリン酸塩C−O結合の活性化に対するアリルハリド結合の選択性を実証している.
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