On the Validity of Au-vinylidenes in the Gold-Catalyzed 1,2-Migratory Cycloisomerization of Skipped Propargylpyridines

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• 作者：Yuanzhi Xia ; Alexander S. Dudnik ; Yahong Li ; Vladimir Gevorgyan
• 刊名：Organic Letters
• 出版年：2010
• 出版时间：December 3, 2010
• 年：2010
• 卷：12
• 期：23
• 页码：5538-5541
• 全文大小：285K
• 年卷期：v.12,no.23(December 3, 2010)
• ISSN：1523-7052

文摘

A mechanism of the Au-catalyzed cycloisomerization of propargylpyridines has been investigated. Both DFT computational and experimental results strongly support generation of a Au-carbene via a cyclization/proton transfer sequence over the previously proposed path involving a Au-vinylidene intermediate. For the β-Si-substituted Au-carbene (G = SiR<sub>3sub>), a 1,2-Si migration was shown to be kinetically favored over a 1,2-H shift. This study highlights the importance of alternative pathways that could explain reactivities commonly attributed to an alkyne−vinylidene isomerization in Au catalysis.