[2 + 3] Annulative Coupling of Tetrahydroisoquinolines with Aryliodonio diazo compounds To Access 1,2,4-Triazolo[3,4‑<i>a</i>]isoquinolines

Base promoted one-pot annulative coupling of 1,2,3,4-tetrahydro­isoquinolines (THIQs) with hypervalent iodine­(III) species aryliodonio diazo compounds has been devised for the direct construction of 1,2,4-triazolo­[3,4-a]­isoquinoline derivatives at room temperature in open air for the first time. This approach involves [2 + 3] cascade annulation of nucleophilic THIQ with an electrophilic aryliodonio diazo compound via N–H and α-C1­(sp3)–H difunctionalization of THIQ.