カルボキシルアンヒドリドとアリルボロン酸のパラジウム触媒のクロスカップリング反応: DFT研究
Lukas J Goossen1, Debasis Koley, Holger L Hermann
1Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany. goossen@chemie.uni-kl.de
Journal of the American Chemical Society
|August 4, 2005
まとめ
この研究では,DFT計算を使用して,鈴木反応をモデル化しました. アニオンパラジウム複合体は5座標の中間物質ではなく,よりよい炭素電粒子の調整により,より高い触媒活性を示します.
科学分野:
- 有機金属化学 有機金属化学
- コンピューティング・ケミストリー
- カタリシス カタリシス カタリシス
背景:
- スズキ反応は,広く使われているクロスカップリング法です.
- 反応メカニズムの理解は,触媒プロセスを最適化するために不可欠です.
- パラジウム触媒による変換は,有機合成において不可欠である.
研究 の 目的:
- モデルシステムとしてフェニルボロン酸と酸アンヒドリドを用いて,鈴木反応の触媒機構を解明する.
- 触媒サイクルにおける中性対アニオンパラジウム複合体の役割を調査する.
- 触媒活動に対する中間構造の影響を調査する.
主な方法:
- 密度関数理論 (DFT) の計算が採用されました.
- BP86/6-31Gレベルの理論が利用されました.
- 中性とアニオン性という2つの異なる触媒サイクルを分析した.
主要な成果:
- 計算された反応プロファイルは実験観察とよく一致し,両経路の適度な活性化エネルギーを示しています.
- 両方の触媒サイクルでは,主にシス構成の正方形平面パラジウム (((II)) ディフォスフィンの中間物質が含まれる.
- このモデルシステムで5座標パラジウム (II) の中間物質の証拠は見つかりませんでした.
- アニオン複合体は,炭素電ophilesの優れた調整に起因する,強化された触媒活性を示します.
結論:
- この研究は,鈴木反応モデルに関する詳細なメカニズム的な洞察を提供します.
- アニオンパラジウム複合体は,5座標の中間体ではなく,より強い電粒子の結合を通じて触媒を強化する可能性があります.
- 伝達処理のステップは,フォスフィンリガンドの解離と,移行状態のブリッジングアセテート塩基を含む.
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