Acid-mediated [3+3] cycloaddition of 伪-EWG-伪-formyl ketene-S,S-acetals and 伪-carbamoyl ketene-S,S-acetals: a new approach to 2-pyridone derivatives

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• 作者：Xiao-Dan Han ^{hanxd1956@163.com" class="auth_mail" title="E-mail the corresponding author hanxd391@163.com" class="auth_mail" title="E-mail the corresponding author} ; Hui-Bin Wang ; Ju-Wu Hu ; Wei Xiong ; Jian-Ping Fu ; Ren-Guo Zhu ; Zhao-Yang Deng ; Guo-Liang Xu ; Xiong-Hui Li
• 关键词：2-Pyridone derivatives ; 伪-EWG-伪-formyl ketene-S ; S-acetals ; 伪-Carbamoyl ketene-S ; S-acetals ; [3+3] annulation reaction
• 刊名：Tetrahedron Letters
• 出版年：2015
• 出版时间：18 November 2015
• 年：2015
• 卷：56
• 期：46
• 页码：6444-6447
• 全文大小：652 K

文摘

A series of 2-pyridone derivatives have been synthesized via a formal [3+3] annulation strategy starting from readily available 伪-EWG-伪-formyl ketene-S,S-acetal 1 and 伪-carbamoyl ketene-S,S-acetals 2 in the presence of CH₃COOH at 80 °C in excellent yields (91–98%). A mechanism involving sequential Baylis–Hillman reaction, intramolecular cycloaddition, Michael addition, and alkylthiol elimination processes for this novel reaction is described in the Letter. In addition, substituted 1-aryl pyridine-2(1H)-ones 4 have also been prepared in high yields via a Cu(OAc)₂-mediated three-component reaction of 1, 2, and aryl boronic acid.