An N-heterocyclic carbene-catalyzed formal [5 + 5] reaction between enals and furanones that generates multisubstituted coumarins in a single step is reported. Five atoms in each of the substrates are involved in this catalytic process to form a benzene and a lactone ring. The power of the method is further demonstrated in metal-free total syntheses of several natural products (defucogilvocarcins M, E, and V) bearing coumarin as the key structural motif.

中文翻译：

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碳催化的香豆素构建和全合成脱呋基新霉素的形式[5 + 5]反应

据报道，在烯醛和呋喃酮之间的N杂环卡宾催化的正式[5 + 5]反应可在一个步骤中生成多取代的香豆素。每个底物中的五个原子参与该催化过程以形成苯和内酯环。该方法的功效在以香豆素为关键结构基序的几种天然产物（去甲福尔霉素M，E和V）的无金属全合成中得到了进一步证明。