Lukoyanov Alexander A, Aksenova Svetlana A, Tabolin Andrey A, Sukhorukov Alexey Yu
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prosp. 47, Moscow, 119991, Russian Federation.
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, Moscow, 119334, Russian Federation.
Org Biomol Chem. 2024 May 8;22(18):3615-3621. doi: 10.1039/d4ob00391h.
The reaction of 3-halo-5,6-dihydro-4-1,2-oxazine -oxides with arynes was studied. Arynes were generated from -silylaryl triflates and underwent consecutive [3 + 2]-cycloaddition/[4 + 2]-cycloreversion with -oxides leading to substituted 3-vinyl-benzisoxazoles in high yields. In the presented sequence, 1,2-oxazine -oxides act as surrogates of rarely employed unsaturated nitrile oxides. A broad substrate scope was demonstrated. The influence of the substitution pattern of an aryne on the reaction outcome was determined. In the presence of bulky substituents, polycyclic 4,4a-dihydro-3-benzofuro[3,2-][1,2]oxazines were selectively formed. Mechanistic schemes for the observed reaction pathways were proposed. The synthetic utility of the products was demonstrated by their follow-up modifications.
研究了3-卤代-5,6-二氢-4H-1,2-恶嗪-4-氧化物与芳炔的反应。芳炔由-甲硅烷基芳基三氟甲磺酸酯生成，并与-氧化物连续进行[3+2]-环加成/[4+2]-环反转反应，以高收率生成取代的3-乙烯基苯并异恶唑。在所示的反应序列中，1,2-恶嗪-4-氧化物作为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。确定了芳炔的取代模式对反应结果的影响。在存在庞大取代基的情况下，选择性地形成了多环4,4a-二氢-3-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。通过后续修饰证明了产物的合成效用。
