Thermally Induced [3 + 2] Cycloaddition of Alkynyl-Tethered Diazoamides: Synthetic and Mechanistic Insights

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• 作者：Cheng Zhang ; Jingjing Huang ; Lihua Qiu ; Xinfang Xu
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：December 2, 2016
• 年：2016
• 卷：18
• 期：23
• 页码：6208-6211
• 全文大小：403K
• ISSN：1523-7052

文摘

A general and unprecedented thermally induced formal [3 + 2] cycloaddition has been developed that provides a general access to fused lactam derivatives in high to excellent yields with broad substrate scope. In comparison with the reported metal-catalyzed carbene/alkynyl metathesis, this is the only example in this area under catalyst-free conditions with excellent selectivity. Mechanistic studies indicate that the 3H-pyrazole is the key intermediate in this cascade reaction, which is confirmed spectroscopically for the first time.