Lewis Acid-Promoted Three-Component Reactions of Propargylic Alcohols with 2-Butynedioates and Secondary Amines

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• 作者：Guangwei Yin ; Yuanxun Zhu ; Ping Lu ; Yanguang Wang
• 刊名：Journal of Organic Chemistry
• 出版年：2011
• 出版时间：November 4, 2011
• 年：2011
• 卷：76
• 期：21
• 页码：8922-8929
• 全文大小：464K
• 年卷期：v.76,no.21(November 4, 2011)
• ISSN：1520-6904

文摘

We report herein a three-component reaction of propargylic alcohols with 2-butynedioates and secondary amines, which furnished functionalized dihydroazepines. In the cases where benzylmethylamine and benzyl-i-propylamine were used as the secondary amine, the reaction afforded 2,5-dihydro-1H-pyrroles and 2,3-dihydro-1H-pyrroles, respectively, as the major product along with the desired dihydroazepines. The reaction mode depends on the electronic and steric effect of the substitutents on the secondary amines used. A tentative mechanism for this cascade process is postulated. The key intermediate is ascribed to 1,3,4-pentatrien-1-amine, which is formed by trapping the in situ generating allenic carbocation with enamine. Because of the reactivity of 1,3,4-pentatrien-1-amine formed, different products were thus formed.