A metal-free approach for the synthesis of 5-trifluoromethyl-1,2,4-triazoles via I₂-mediated [4+1] annulation of readily available trifluoroacetimidohydrazides and methyl ketones has been achieved. The transformation involves iodination/Kornblum oxidation, intermolecular dehydration condensation and an iodine-mediated intramolecular cyclization/aromatization sequence. The developed protocol can be easily scaled up to 3 mmol scale without obvious efficiency decrease and be implemented by a consecutive one-pot manner.

中文翻译：

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通过三氟乙酰氨基酰肼和甲基酮的无金属环化合成 5-三氟甲基-1,2,4-三唑

已经实现了一种通过 I ₂介导的 [4+1] 环化容易获得的三氟乙酰氨基酰肼和甲基酮来合成 5-三氟甲基-1,2,4-三唑的无金属方法。该转化包括碘化/Kornblum 氧化、分子间脱水缩合和碘介导的分子内环化/芳香化序列。开发的协议可以很容易地扩展到 3 mmol 规模而不会明显降低效率，并且可以通过连续的一锅方式实施。