Mechanism of the Ru鈥揂llenylidene to Ru鈥揑ndenylidene Rearrangement in Ruthenium Precatalysts for Olefin Metathesis

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• 作者：Eva Pump ; Christian Slugovc ; Luigi Cavallo ; Albert Poater
• 刊名：Organometallics
• 出版年：2015
• 出版时间：July 13, 2015
• 年：2015
• 卷：34
• 期：13
• 页码：3107-3111
• 全文大小：374K
• ISSN：1520-6041

文摘

The intramolecular allenylidene RuCl₂(PR₃)₂(C鈺怌鈺怌Ph₂) to indenylidene RuCl₂(PR₃)₂(Ind) rearrangement that occurs during the synthesis of Ru-based precatalysts for olefin metathesis is presented. In the absence of acid, the ring closure via C鈥揌 activation was shown to be unfavored for energy barriers up to 70 kcal/mol. Thus, it turned out to be HCl (or other acid) that plays a crucial role during formation of the indenylidene, as the upper energy barrier decreases to a reasonable 35 kcal/mol. Moreover, we proved computationally that depending on the nature of the phosphine the intramolecular rearrangement is either facilitated (PPh₃) or slightly hampered (PCy₃), which is in line with experimental results.