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ニトリルを含むテンプレートによるパラジウム触媒によるメタ選択的C-H結合活性化:選択性のメカニズムと起源に関する計算研究

Yun-Fang Yang¹, Gui-Juan Cheng, Peng Liu

¹Laboratory of Computational Chemistry and Drug Design and Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, China.

Journal of the American Chemical Society

|December 10, 2013

まとめ

密度関数理論は,Pd-Agヘテロダイマーが,ニトリルテンプレートを使用したメタ選択的なC-Hオレフィネーションの鍵であることを明らかにしています. これは,パラジウムをメタポジションに誘導し,反応結果を制御します.

科学分野:

有機金属化学有機金属化学
カタリシスカタリシスカタリシス
コンピューティング・ケミストリー

背景:

パラジウムによって触媒化されたC-H機能化は,有機合成に不可欠である.
これらの反応における地域選択性,特にメタ選択性を達成することは,依然として課題です.
ニトリルを含むテンプレートは,C-H活性化を誘導するための戦略を提供します.

研究の目的:

Pd (((II)) -触媒化されたC-Hオレフィネーションにおけるメタ地域選択性のメカニズムと起源を解明する.
反応における異なるパラジウム触媒種の役割を調査する.
ニトリルテンプレートが地域選択性にどのように影響するかを理解するために.

主な方法:

密度関数理論 (DFT) の調査が採用されました.
4つの主要なステップの分析:C-H活性化,アルケンの挿入,β-ヒドリドの除去,および還元性の除去.
さまざまな触媒種の評価:モノメリックPd(II),ジメリックPd2(OAc) 4,ヘテロジメリックPdAg(OAc) 3,トリメリックPd3(OAc) 6.

主要な成果:

協調メタリエーション-デプロトネーション (CMD) 経路を経由するC-H活性化ステップは,速度と地域選択性を決定する.
Pd-Agヘテロジメア移行状態は,メタ-C-H活性化のための最も有利な経路として特定されました.
ニトリルグループはAgと協調し,Pdをメタ選択的C-H活性化に配置し,二次元Pd2 ((OAc) 4) のエネルギー優位性を上回る.

結論:

Pd-Agのヘテロディメアメカニズムは,これらの反応で観察された高いメタ選択性を説明します.
モノメアおよびトリメア Pd 種は,より高い活性化エネルギーを必要とする,オルト製品に好意を示します.
テンプレート構造と歪みエネルギーは,反応機構と地域選択性に大きな影響を及ぼし,新しい触媒設計の機会を提供します.

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