An efficient and rapid protocol for the synthesis of 3,4-disubstituted and 3,4,5-trisubstituted isoxazoles under catalyst-free conditions is described. This protocol involves pre-oxidation of aldoxime into nitrile oxide using diacetoxyiodobenzene. The in situ generated nitrile oxide was trapped with dipolarophiles for the formation of functionally rich isoxazoles via [3+2] cycloaddition.

中文翻译：

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通过[3 + 2]腈氧化物的环加成反应，高价碘介导的二取代和三取代的异恶唑的合成

描述了在无催化剂条件下合成3,4-二取代和3,4,5-三取代异恶唑的有效而快速的方案。该方案涉及使用二乙酰氧基碘苯将醛肟预先氧化为一氧化氮。原位产生的一氧化二氮被亲极性试剂捕获，通过[3 + 2]环加成反应形成功能丰富的异恶唑。