Simple Aza-Conjugate Addition Methodology for the Synthesis of Isoindole Nitrones and 3,4-Dihydroisoquinoline Nitrones

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• 作者：Lucy R. Peacock ; Robert S. L. Chapman ; Adam C. Sedgwick ; Mary F. Mahon ; Dominique Amans ; Steven D. Bull
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：February 20, 2015
• 年：2015
• 卷：17
• 期：4
• 页码：994-997
• 全文大小：345K
• ISSN：1523-7052

文摘

Aryl-aldehydes containing ortho-substituted 伪,尾-unsaturated carboxylic acid derivatives react with hydroxylamine to afford reactive N-hydroxy-carbinolamine intermediates that undergo intramolecular aza-conjugate addition reactions to afford isoindole nitrones and 3,4-dihydroisoquinoline nitrones in good yield. Conditions have been developed to reduce these isoindole nitrones to their corresponding hydroxylamine, enamine, and amine derivatives. Isoindole nitrones react with dimethyl acetylenedicarboxylate (DMAD) via a [4 + 2]-cycloaddition/deamination pathway to afford substituted naphthalene derivatives, while 3,4-dihydroisoquinoline nitrones react with DMAD via a [1,3]-dipolar cycloaddition pathway to afford tricyclic heteroarenes.