プロリン触媒によるアルファ-アミノキシル化における選択性の起源

Paul Ha-Yeon Cheong¹, K N Houk

¹Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.

Journal of the American Chemical Society

|October 28, 2004

まとめ

密度関数理論では,プロリン触媒によるアルファ-アミノキシル化を研究した. この研究では,最も有利な経路は,ニトロソベンゼンに対するエナミンの攻撃を含むことが判明しました.

科学分野:

有機化学オーガニック・ケミストリー
コンピューティング・ケミストリー

背景:

プロリンは多用途の有機触媒である.
アルファ-アミノキシル化反応は重要な合成変換である.

研究の目的:

プロリン触媒によるアルファ-アミノキシル化反応の反応機構を解明する.
地域選択性とステレオ選択性を支配する要因を決定する.

主な方法:

密度関数理論 (DFT) の計算は,理論のB3LYP/6-31G (d) レベルを使用しています.
移行構造,反応経路,エネルギープロファイルの分析.

主要な成果:

最も有利な移行構造は, (E) -プロリンエナミンがニトロソベンゼン (nitrosobenzene) の酸素原子に核愛的に攻撃することを含む.
陽子の移転は,カルボキシル酸から移行状態の窒素原子に起こります.
窒素のより高い基本性のために,窒素よりも酸素に対するエナミンの攻撃が好ましい.
以前提案されたズウィテリオンエナミニウム経路は,エネルギー的に不利であることが判明しました.

結論:

この研究は,プロリン触媒によるアルファ-アミノキシル化の詳細なメカニズムを明らかにしている.
地域選択性は,窒素の相対的基礎性および電友性の攻撃の好ましい場所によって支配されます.
この発見は,この重要な触媒反応の最適化のための理論的基礎を提供します.

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