バイモレキュラーカップリングは,迅速な開始オレフィンメタテシス触媒の分解のベクトルとして使用されます
Gwendolyn A Bailey1, Marco Foscato2, Carolyn S Higman1
1Center for Catalysis Research and Innovation, and Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , ON , Canada K1N 6N5.
Journal of the American Chemical Society
|April 14, 2018
まとめ
素早く発動する,フォスフィンのないルテニウム触媒は,プロペンの除去だけでなく,メチリデンの結合によって分解します. この二分子結合経路は,これらの重要なオレフィン転化触媒の不安定性を理解するために重要である.
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
- オーガニック・シンセシス オーガニック・シンセシス
背景:
- オレフィン転化は有機合成の重要な反応であり,炭素-炭素二重結合の形成を可能にします.
- 素早く発動する,フォスフィンのないルテニウム触媒は,反応性において優れているが,急速な分解に苦しむ可能性がある.
- 以前の研究では,メタラサイクロブタンの中間産物からプロペンのβ除去が主要な分解経路として特定されました.
研究 の 目的:
- オレフィンメタテシスにおける様々な素早く発動する,フォスフィンフリールテニウム触媒の分解経路を調査する.
- 触媒の開始速度とその分解機構と相関する.
- β除去以外の代替分解経路の直接的な証拠を提供すること.
主な方法:
- ホヴェイダ (HII),グレラ (nG),ピアス (PII),グラブスIII (GIII),ダイアニリン (DA) の触媒を含む,フォスフィンフリールテニウム触媒の一連の合成と特徴付け.
- 解体メカニズムを調査するための運動研究と分子レベルの計算分析.
- 暫定的に安定したメチリデン・ルテニウム中間物の制御された分解実験.
主要な成果:
- β除去は,HII,GN,PII,DA触媒のプロペンの25-40%しか与えず,GIIIのプロペンは与えられない.
- メチリデネ中間物質 (Ru-1) の二分子結合による競合する分解経路が特定されました.
- メチリデン結合の直接的な証拠は,安定したメチリデンルテニウム添加物の分解から得られた.
結論:
- 双分子メチリデン結合は,メチリデンルテニウム中間物質 (Ru-1) の不安定性に大きく貢献しています.
- この結合経路は,素早く発動する,フォスフィンフリーなオレフィンメタテシス触媒の主要な分解経路である.
- これらの分解経路を理解することは,より安定で効率的なメタテシス触媒の設計に不可欠です.
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