The stereoselective 5-endo-trig oxygenative cyclization of α,β-unsaturated oximes was achieved using molecular oxygen (O₂) and a manganese catalyst. Several 4-hydroxy-4,5-dihydroisoxazoles were obtained in high yields by directly incorporating O₂ from the atmosphere (eliminating the necessity for a pure oxygen environment) and using an unprecedentedly low loading of Mn(acac)₃ (as little as 0.020 mol %) without additional additives. Because of its desirable features, such as operational simplicity, inexpensive catalyst, mild reaction conditions (open flask conditions at room temperature), and broad substrate compatibility, this novel reaction provides an attractive synthetic approach to producing 4-hydroxy-4,5-dihydroisoxazoles.

中文翻译：

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空气和环境条件下锰催化 α,β-不饱和肟的 5-Endo-trig 氧化环化反应合成 4,5-二氢异恶唑

_{使用分子氧（O 2}）和锰催化剂实现了α,β-不饱和肟的立体选择性5-内-触发氧化环化。通过直接从大气中引入 O ₂（消除了纯氧环境的必要性）并使用空前低的 Mn(acac) ₃负载量（低至 0.020），以高收率获得了几种 4-羟基-4,5-二氢异恶唑。mol %)，无需额外添加剂。由于其理想的特点，例如操作简单、催化剂便宜、反应条件温和（室温下的开瓶条件）和广泛的底物兼容性，这种新颖的反应为生产 4-羟基-4,5-二氢异恶唑提供了一种有吸引力的合成方法。