N,N,N′,N′‐Tetramethylchloroformamidinium Chloride‐Mediated Cyclizations of β‐Oxo Amides: Facile and Divergent One‐Pot Synthesis of Substituted 2H‐Pyrans, 4H‐Pyrans and Pyridin‐2(1H)‐ones |
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Authors: | Yan Wang Xin Xin Yongjiu Liang Yingjie Lin Haifeng Duan Dewen Dong |
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Abstract: | An efficient and divergent one‐pot synthesis of substituted 2H‐pyrans, 4H‐pyrans and pyridin‐2(1H)‐ones from β‐oxo amides based on the selection of the reaction conditions is reported. Mediated by N,N,N′,N′‐tetramethylchloroformamidinium chloride, β‐oxo amides underwent intermolecular cyclizations in the presence of triethylamine at room temperature to give substituted 2H‐pyrans in high yields, which could be converted into substituted 4H‐pyrans in the presence of sodium hydroxide in ethanol at room temperature, or into substituted pyridin‐2(1 H)‐ones under reflux. |
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Keywords: | cyclization iminium salts β ‐oxo amides 2H‐pyrans 4H‐pyrans pyridin‐2(1H)‐ones |
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