ウィルキンソンの触媒のフッ素アナログと予期せぬPh-Cl活性化
Vladimir V Grushin1, William J Marshall
1Central Research & Development, E. I. DuPont de Nemours and Co., Inc., Experimental Station, Wilmington, Delaware 19880-0328, USA. vlad.grushin-1@usa.dupont.com
Journal of the American Chemical Society
|March 12, 2004
まとめ
研究者らは,ウィルキンソンの触媒のフッ素アナログを合成した. この新しい化合物である[Ph3P]3RhFは,クロロアレン中のC-Cl結合を意外に活性化させ,有機金属化学における重要な進歩となった.
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
- フロアンの化学的性質
背景:
- ウィルキンソンの触媒は,様々な有機変異のための確立された均質な触媒です.
- アリル塩化物 (C-Cl) 結合の惰性性は,合成化学における課題となっている.
- 金属・フッ化物複合体は,そのユニークな反応性パターンに注目されています.
研究 の 目的:
- ウィルキンソン触媒のフッ素アナログを合成し,特徴づけるために, [(Ph3P) 3RhF] (1).
- 化合物1の反応性,特に惰性C-Cl結合に対する反応性を調査する.
- 化合物1による新しいPh-Cl結合活性化のメカニズムを解明する.
主な方法:
- フッ化物の同類である[(Ph3P) 3RhF] (1) の合成
- 顕微鏡および結晶学的技術を用いた化合物1の完全な特徴付け.
- 非活性化クロロアレンと化合物1を対象とした反応性試験
主要な成果:
- フッ化物のアナログ [(Ph3P) 3RhF] (1) が成功裏に合成され,特徴づけられました.
- 化合物1は,ウィルキンソンの触媒に似た溶液の行動と固体幾何学を示している.
- 化合物1は,活性化されていないクロロアレンのC-Cl結合に対する前例のない反応性を示しています.
- アクティベーションメカニズムは,フッシンリガンドへのフッ素移転とRhへのフェニル移転を含み,シグマ-フェニルロジウム中間物質を形成します.
結論:
- ウィルキンソンの触媒のフッ素アナログはユニークな反応性を示し,惰性アリル塩化物結合の活性化を可能にします.
- この発見は,触媒性C-Cl結合の機能化のための新しい道を開く.
- 提案されたメカニズムは,活性化プロセス中の新しいリガンドと金属の変換を強調しています.
関連する概念動画
Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
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ortho–para-Directing Deactivators: Halogens
Halogens are ortho–para directors. They are more electronegative than carbon. Therefore, as ring substituents, they can withdraw electrons through the inductive effect and deactivate the aromatic ring towards electrophilic substitution. Halogens also have an electron-donating resonance effect on the ring, which influences the orientation of the incoming electrophile. If an electrophile attacks at the ortho or the para position, the halogen donates electrons and stabilizes the intermediate...
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
The Wittig reaction, which converts aldehydes or ketones to alkenes using phosphorus ylides, proceeds through a nucleophilic addition‒elimination process.
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
Cycloaddition Reactions: MO Requirements for Photochemical Activation
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