半サンドイッチルテニウムカルベンの複合体 内部アルキンのリンクトランス水素化およびジェム水素化
Alexandre Guthertz1, Markus Leutzsch1, Lawrence M Wolf1
1Max-Planck-Institut für Kohlenforschung , Mülheim/Ruhr 45470, Germany.
Journal of the American Chemical Society
|February 13, 2018
まとめ
ルテニウム触媒は,内部アルキンのトランス水素化によってEアルケンの合成を達成する. 機械学的研究により,金属cyclopropeneとcarbeneの中間物質が発見され,競合するジェム-水素化と製品形成の経路が説明される.
科学分野:
- 有機金属化学
- カタリシス
- 反応メカニズム
背景:
- 内部アルキンの水素化は通常Zアルケンを生成する.
- [Cp*Ru]ベースの触媒は異常なステレオ選択性を示し,Eアルケンを形成する.
- この非正統なトランス水素化の正確なメカニズムは不明である.
研究 の 目的:
- [Cp*Ru]ベースの触媒を用いた内部アルキン水素化の包括的なメカニズムを解明する.
- メタラサイクロプロペンとルテニウムカルベンの形成と運命を調査する.
- トランスヒドロジネーションとジェムヒドロジネーションの競争を左右する要因を理解する.
主な方法:
- 組み合わせた実験調査と計算研究 (密度関数理論 - DFT,結合クラスター - CCSD ((T)).
- パラ水素誘発偏移 (PHIP) 核磁気共振 (NMR) スペクトロスコーピー
- カーベンの中間物質,特にプロパルギル−OR群の分離とX線 difrractionの特徴づけ
主要な成果:
- メタラサイクロプロペンの中間物質が主に形成され,H2の協調的なトランス配送によってEアルケーンに導かれます.
- 競合する経路は,アルキンπ結合の正式なゲム水素化によってルテニウムカルベンの中間物質を形成する.
- カーベンの中間物質は,E-アルケーン,位置性同位体,アルケーン,またはサイクロプロパネーションやリング膨張などのさらなる反応を引き起こす.
結論:
- この研究は,[Cp*Ru]触媒によるアルキンの水素化の詳細なメカニズムを理解し,実験的観測と理論的予測を調和させています.
- ゲムヒドロジネーションによるカルベンの中間物質の形成は,競合する経路を説明し,新しい合成変換を可能にします.
- プロパルギルアルコールの高度な選択的トランス水素化が達成され,調製の有用性を示した.
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