Regiodivergent heterocyclization: a strategy for the synthesis of substituted pyrroles and furans using α-formyl ketene dithioacetals as common precursors
作者:Ting Wu、Ling Pan、Xianxiu Xu、Qun Liu
DOI:10.1039/c3cc48546c
日期:——
challenging task. We report here that 5-alkylthio-pyrroles, 4-alkylthiocarbonyl-pyrroles and 2-alkylthio-4-tosyl-furans can be prepared, selectively, in a single operation using the readily available alpha-formyl ketene dithioacetals as common precursors, through their regiodivergent heterocyclization with alpha-acidic isocyanides controlled by the choice of suitable catalysts/promoters.
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