An efficient protocol for the construction of 3‐carbonyl functionalized 4‐pyrones has been developed using a transition‐metal free thermal cascade reaction of diazodicarbonyls with β‐enamino esters or β‐enamino ketones. This reaction proceeds via cascade carbene generation, ketene formation via thermal Wolff‐rearrangement, nucleophilic addition, intramolecular cyclization, and elimination. This protocol provides a rapid synthetic route to diverse 2,3,5‐trisubstituted 4‐pyrone derivatives.

中文翻译：

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通过重氮二羰基化合物的热沃尔夫重排，实现不同的3-羰基官能化的4-吡喃酮的无过渡金属区域选择性构建

利用重氮二羰基与β-烯胺酸酯或β-烯胺酮的无过渡金属热级联反应，开发了一种有效的构建3-羰基官能化的4-吡喃酮的方法。该反应通过级联卡宾生成，通过热Wolff重排形成烯酮，亲核加成，分子内环化和消除而进行。该协议为各种2,3,5-三取代的4-吡喃酮衍生物提供了快速的合成途径。