Electrochemical\nRegioselective C(sp<sup>2</sup>)–H\nBond Chalcogenation of Pyrazolo[1,5‑<i>a</i>]pyrimidines\nvia Radical Cross-Coupling at Room Temperature

Herein, we disclose an electrochemical approach for the\nC(sp<sup>2</sup>)–H chalcogenation of pyrazolo[1,5-<i>a</i>]pyrimidines. This technique offers an oxidant and catalyst-free\nprotocol for achieving regioselective chalcogenation of pyrazolo[1,5-<i>a</i>]pyrimidines. The procedure uses only 0.5 equiv. of diaryl\nchalcogenides which underscores the atom economy of the protocol.\nKey attributes of this methodology include mild reaction conditions,\nshort reaction time, utilization of cheap electrode materials, and\neco-friendly reaction conditions. Cyclic voltammetry studies and radical\nquenching experiments revealed a radical cross-coupling pathway for\nthe reaction mechanism.