C–H Amination of Unactivated Arenes Through a Dearomative (3+2) Cycloaddition

The C–H amination of arenes is an important tool for the synthesis of arylamines that provides advantages over tradi-tional methods, which typically require pre-functionalized arene substrates, costly catalysts, strong bases or high temperatures. Most often, the direct C–H amination of arenes has been achieved through transition metal or photore-dox catalysis. In this study, we report that azidium ions enable the telescoped C–H amination of unactivated arenes through a cycloaddition and C–N/N–N bond cleavage sequence. First, a dearomative (3+2) cycloaddition reaction between arenes and azidium ions generates fused triazolinium adducts. Subsequent treatment of latter with a mild base, followed by thermolysis at moderate temperatures, achieves the synthesis of a diverse range of arylamines with a broad substrate scope. The synthetic versatility of this approach is showcased in the late-stage diversification of nat-ural products, pharmaceuticals, and functional organic materials. Employing this protocol, a regioselective double C–H arylamination of [9]-cycloparaphenylene was achieved for the first time.