In Situ Generated TEMPO Oxoammonium Salt Mediated Tandem Cyclization of β-Oxoamides with Amine Hydrochlorides for the Synthesis of Pyrrolin-4-ones.
In Situ Generated TEMPO Oxoammonium Salt Mediated Tandem Cyclization of β-Oxoamides with Amine Hydrochlorides for the Synthesis of Pyrrolin-4-ones.
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DOI：
10.1021/acs.joc.7b00686
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发表时间：
2017-05
期刊：
影响因子：
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通讯作者：
Xuna Zhao;Tongxin Liu;N. Ma;Guisheng Zhang
中科院分区：
文献类型：
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作者：
Xuna Zhao;Tongxin Liu;N. Ma;Guisheng Zhang
提出了一种新的原位生成的TEMPO氧铵盐介导的一锅串联反应，用于从容易获得的β-草酰胺与盐酸胺直接合成吡咯啉-4-酮。该反应可以容忍各种官能团，是一种在温和的条件下以较高的产率合成高取代吡咯酮的可靠方法。详细的机理研究表明，原位生成的TEMPO氧铵盐在转化过程中起着关键作用，转化过程包括β-草酰胺与胺的缩合反应、与β-草酰胺的顺序氧化偶联、分子内环化和1，2-烷基迁移等步骤。
A novel in situ generated TEMPO oxoammonium salt mediated one-pot tandem reaction has been developed for the straightforward construction of pyrrolin-4-ones from readily available β-oxoamides with amine hydrochlorides. The reaction tolerates various functional groups and represents a reliable method for the synthesis of highly substituted pyrrolin-4-ones in good yields under mild conditions. Detailed mechanistic studies disclosed that TEMPO oxoammonium salt generated in situ was crucial for the transformation involving the formation of enaminone precursors in situ by condensation of the β-oxoamides with amines, followed by sequential oxidative coupling with β-oxoamides, intramolecular cyclization, and 1,2-alkyl migration steps.