Reversible 1,2-Alkyl Migration to Carbene and Ammonia Activation in an N-Heterocyclic Carbene鈥揨irconium Complex

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• 作者：Emmanuelle Despagnet-Ayoub ; Michael K. Takase ; Jay A. Labinger ; John E. Bercaw
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：August 26, 2015
• 年：2015
• 卷：137
• 期：33
• 页码：10500-10503
• 全文大小：329K
• ISSN：1520-5126

文摘

Addition of trimethylphosphine to a bis(phenolate)benzylimidazolylidene(dibenzyl)zirconium complex induces migration of a benzyl ligand from the metal center to the C_carbene atom. This process may be reversed, resulting in C_sp³鈥揅_sp³ activation, by abstraction of the phosphine, an example of regulated, reversible alkyl migration. Addition of ammonia to the dibenzyl complex results in migration of one benzyl group and protonolysis of the other to generate a bis(NH₂)-bridged dimer via an NMR-observable intermediate NH₃ adduct.