[4 + 2] Cycloadditions of N-Alkenyl Iminium Ions: Structurally Complex Heterocycles from a Three-Component Diels−Alder Reaction Sequence

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• 作者：Nihar Sarkar ; Abhisek Banerjee ; Scott G. Nelson
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：July 23, 2008
• 年：2008
• 卷：130
• 期：29
• 页码：9222 - 9223
• 全文大小：121K
• 年卷期：v.130,no.29(July 23, 2008)
• ISSN：1520-5126

文摘

N-Alkenyl iminium ions serve as conduits to three-component [4 + 2] cycloaddition reactions accessing structurally and stereochemically diverse piperidine derivatives. These cationic 2-azadienes participate in endo- or exo-selective [4 + 2] cycloadditions with electron-rich and neutral alkene dienophiles to generate a tetrahydropyridinium ion as the initial cycloadduct. In situ nucleophilic addition to the cycloaddition-derived iminium ion completes the three-component coupling sequence and affords a versatile synthesis of structurally complex piperidines.