Acid-mediated [3+3] cycloaddition of α-EWG-α-formyl ketene-S,S-acetals and α-carbamoyl ketene-S,S-acetals: a new approach to 2-pyridone derivatives
作者:Xiao-Dan Han、Hui-Bin Wang、Ju-Wu Hu、Wei Xiong、Jian-Ping Fu、Ren-Guo Zhu、Zhao-Yang Deng、Guo-Liang Xu、Xiong-Hui Li
DOI:10.1016/j.tetlet.2015.09.152
日期:2015.11
have been synthesized via a formal [3+3] annulation strategy starting from readily available α-EWG-α-formyl ketene-S,S-acetal 1 and α-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, Michaeladdition, and alkylthiol elimination processes for this novel reaction is described