非対称的移転水素化と二機能鉄 ((II) 水素:実験は計算を満たす
Lorena De Luca1, Alessandro Passera1, Antonio Mezzetti1
1Department of Chemistry and Applied Biosciences , ETH Zurich , Zurich 8093 , Switzerland.
Journal of the American Chemical Society
|January 10, 2019
まとめ
キラル鉄水化物複合体 (5) は非対称ケトン水素化を触媒とする. 鉄酸化物前駆体から形成され,独特のマクロサイクリック構造とイソニトリルリガンドにより高いエナンチオセレクティブ性を達成します.
科学分野:
- 有機金属化学
- 非対称な触媒
- 鉄複合体
背景:
- チラルのN2P2マクロサイクルは,移行金属触媒における有効なリガンドである.
- 鉄複合体は,貴金属触媒の持続可能な代替品としてますます研究されています.
- アシンメトリック・トランスファー・ヒドロゲネーション (ATH) は,キラル分子の合成に不可欠である.
研究 の 目的:
- キラル鉄複合体を用いてケトンの非対称的移転水素化における触媒的に活性な種を特定する.
- 反応メカニズムを解明し,エナチオ選択性を支配する要因を理解する.
- 新しい鉄水化物とアルコキシード複合体を特徴付ける.
主な方法:
- 鉄複合体の合成と特徴付け
- ステキオメトリック反応は,探査反応経路です.
- 構造分析のための核磁気共振 (NMR) スペクトロスコーピー.
- 密度関数理論 (DFT) の計算により,機械的洞察と構造的解明が行われる.
主要な成果:
- 触媒的に活性な種はキラル鉄水化物複合体,cis-β-[FeH ((CNCEt3) ((1)) ]BF4 (5).
- 複合体5は,鉄2プロポキソ複合体 (8a) からH除去によって形成される.
- 鉄水化物は,アセトフェノンのカルボニル基を挿入し,ダイアステレオ同位体アルコホラト複合体 (10Rと10S) を形成する.
- DFT計算は,鉄アルコキシドを静止状態とする二機能メカニズムをサポートしています.
- ステレオ化学モデルは,アセトフェノンの水素化に対する高いエナチオ選択性を正確に予測する.
結論:
- キラル鉄水化物複合体 (5) は,非対称移動水素化のための非常に効果的な触媒である.
- 硬いマクロサイクリックリガンドと大容量のイソニトリルリガンドの組み合わせにより,高いエナチオ選択性が生じる.
- この研究は,鉄触媒による非対称な水素化反応に関する貴重な機械的洞察を提供します.
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