The Reaction Mechanism of the Hydroamination of Alkenes Catalyzed by Gold(I)-Phosphine: The Role of the Counterion and the N-Nucleophile Substituents in the Proton-Transfer Step

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• 作者：G&aacute ; bor Kov&aacute ; cs ; Gregori Ujaque ; Agustí ; Lledó ; s
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：January 23, 2008
• 年：2008
• 卷：130
• 期：3
• 页码：853 - 864
• 全文大小：592K
• 年卷期：v.130,no.3(January 23, 2008)
• ISSN：1520-5126

文摘

The reaction mechanism of the gold(I)-phosphine-catalyzed hydroamination of 1,3-dienes wasanalyzed by means of density functional methods combined with polarizable continuum models. Severalmechanistic pathways for the reaction were considered and evaluated. It was found that the most favorableseries of reaction steps include the ligand substitution reaction in the catalytically active Ph₃PAuOTf speciesbetween the triflate and the substrate, subsequent nucleophile attack of the N-nucleophile (benzyl carbamate)on the activated double bond, which is followed by proton transfer from the NH₂ group to the unsaturatedcarbon atom. The latter step, the most striking one, was analyzed in detail, and a novel pathway involvingtautomerization of benzyl carbamate nucleophile assisted by triflate anion acting as a proton shuttle wascharacterized by the lowest barrier, which is consistent with experimental findings.