3-Halo-5,6-dihydro-4<i>H</i>-1,2-oxazine <i>N</i>-oxides as synthetic equivalents of unsaturated nitrile oxides in the [3 + 2]-cycloaddition with arynes: synthesis of substituted 3-vinyl-1,2-benzisoxazoles
作者:Alexander A. Lukoyanov、Svetlana A. Aksenova、Andrey A. Tabolin、Alexey Yu. Sukhorukov
DOI:10.1039/d4ob00391h
日期:——
The reaction of 3-halo-5,6-dihydro-4H-1,2-oxazine N-oxides with arynes was studied. Arynes were generated from o-silylaryl triflates and underwent consecutive [3 + 2]-cycloaddition/[4 + 2]-cycloreversion with N-oxides leading to substituted 3-vinyl-benzisoxazoles in high yields. In the presented sequence, 1,2-oxazine N-oxides act as surrogates of rarely employed unsaturated nitrile oxides. A broad
研究了3-卤代-5,6-二氢-4H -1,2-恶嗪N-氧化物与芳烃的反应。芳烃由邻甲硅烷基芳基三氟甲磺酸酯生成,并与N-氧化物进行连续的[3 + 2]-环加成/[4 + 2]-环化还原,以高产率产生取代的3-乙烯基-苯并异恶唑。在所提出的序列中,1,2-恶嗪N-氧化物充当很少使用的不饱和腈氧化物的替代物。展示了广泛的底物范围。确定了芳基的取代模式对反应结果的影响。在大取代基存在下,选择性地形成多环4,4a-二氢-3H-苯并呋喃并[3,2- c ][1,2]恶嗪。提出了观察到的反应途径的机理方案。产品的合成实用性通过其后续修饰得到了证明。