The venerable 1,3-dipolar cycloaddition has been widely used in organic synthesis for the construction of various heterocycles. However, in its century-long history, the simple and omnipresent aromatic phenyl ring has remained a stubbornly unreactive dipolarophile. Here we report 1,3-dipolar cycloaddition between aromatic groups and diazoalkenes, generated in situ from lithium acetylides and N-sulfonyl azides. The reaction results in densely functionalized annulated cyclic sulfonamide-indazoles that can be further converted into stable organic molecules that are important in organic synthesis. The involvement of aromatic groups in the 1,3-dipolar cycloadditions broadens the synthetic utility of diazoalkenes, a family of dipoles that have been little explored so far and are otherwise difficult to access. The process described here provides a route for the synthesis of medicinally relevant heterocycles and can be extended to other arene-containing starting materials. Computational examination of the proposed reaction pathway revealed a series of finely orchestrated bond-breaking and bond-forming events that ultimately lead to the annulated products.

古老的 1,3-偶极环加成已广泛用于有机合成中，用于构建各种杂环。然而，在其长达一个世纪的历史中，简单且无所不在的芳族苯环一直是一种顽固的非反应性亲偶极体。在这里，我们报告了芳族基团和重氮烯烃之间的 1,3-偶极环加成，由乙炔锂和N-磺酰叠氮化物。该反应产生致密官能化的环状磺酰胺-吲唑，可以进一步转化为稳定的有机分子，这在有机合成中很重要。芳族基团参与 1,3-偶极环加成拓宽了重氮烯烃的合成效用，重氮烯烃是一类偶极分子，迄今为止很少被探索，否则很难获得。此处描述的过程提供了合成药用相关杂环的途径，并且可以扩展到其他含芳烃的起始材料。对所提出的反应途径的计算检查揭示了一系列精心策划的键断裂和键形成事件，这些事件最终导致环化产物。