Formal [4 + 1] Annulation of α-Arylhydrazonoketones and Dimethylsulfoxonium Methylide: One-pot Synthesis of Substituted Pyrazoles and Dihydropyrazoles

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• 作者：Qian Zhang ; Mangfei Yu ; Jingwen Yuan ; Rui Zhang ; Yongjiu Liang ; Jiamei Tian ; Dewen Dong
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：July 15, 2016
• 年：2016
• 卷：81
• 期：14
• 页码：6036-6041
• 全文大小：348K
• 年卷期：0
• ISSN：1520-6904

文摘

A formal [4 + 1] annulation of readily available α-arylhydrazonoketones and trimethylsulfoxonium iodide in the presence of cesium carbonate is described involving a sequential Corey–Chaykovsky reaction and intramolecular nucleophilic cyclization process. Substituted pyrazoles were obtained exclusively from the reactions of α-arylhydrazono-β-oxo-amides and trimethylsulfoxonium iodide in moderate to good yields, whereas the reactions of α-arylhydrazono-β-oxo-ketone/α-arylhydrazono- β-oxo-ester afforded the corresponding dihydropyrazoles in good yields.