エレクトロフィルの親和度:芳香的置換の反応性の測定値である
Gergana Koleva1, Boris Galabov, Judy I Wu
1Department of Chemistry, University of Sofia, Sofia 1164, Bulgaria.
Journal of the American Chemical Society
|September 26, 2009
まとめ
エレクトロフィール・アフィニティ (Ealpha) は,エレクトロフィール芳香置換反応における反応性と地域選択性を定量化します. この新しいメトリックは,ベンゼン誘導体の塩素化,窒素化,ベンジル化に関する実験データと高い相関を示しています.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 物理化学 物理化学
背景:
- エレクトロフィリックアロマティック置換 (S(E) Ar) 反応は,有機合成の基本です.
- 反応活性と地域選択性を支配する要因を理解することは,反応結果を予測するために極めて重要です.
研究 の 目的:
- ベンゼン誘導体の電気的塩化,窒化,アルキル化の反応性と地域選択性を合理化するために.
- これらのプロセスを定量化するために,新しい理論パラメータである電子系親和度 (Ealpha) を導入し,検証する.
主な方法:
- 部分速度因子 (ln f) の文献データと理論的反応性パラメータの比較.
- アレニウムイオン形成中のエネルギー変化に基づいて,電粒子の親和 (Ealpha) の理論的評価.
- Ealpha,原子核における静電電位 (EPN) 値,および実験的な部分速度因子との相関分析.
主要な成果:
- 塩素化,窒素化,およびベンジル化のためのアルファと部分速度因子間の高相関係数 (r > 0.97) が観察されました.
- EPN値と,塩素化と窒素化のための実験的部分速度因子との間に満足のいく相関が見られた.
- ベンジル化の相関関係に不一致が認められ,これはベンジルグループのステリック効果に起因する.
結論:
- エレクトロフィール・アフィニティ (Ealpha) は,S(E) Ar反応における反応性および地域化学を予測するための有用な定量指標である.
- EPN値は,塩素化と窒素化に関連した電子密度の変動を効果的に反映します.
- ステリック・ファクターは,ベンジル群のような大容量の電ophiles を含む反応に著しく影響します.
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