Cupraelectro-Catalyzed Alkyne Annulation: Evidence for Distinct C–H Alkynylation and Decarboxylative C–H/C–C Manifolds

Synthetically meaningful isoindolones were accessed by cupraelectro-catalyzed C–H activation with electricity as terminal oxidant. Thus, a versatile, inexpensive and non-toxic Cu(OAc)2 catalyst enabled broadly applicable C–H/N–H functionali-zations on electron-rich and electron-deficient benzamides with outstanding functional group tolerance and resource-economy. Detailed mechanistic studies provided strong support for a C–H alkynylation mechanism through fast C–H meta-lation, which likewise set the stage for cupraelectro-catalyzed C–H/C–C functionalizations in a decarboxylative fashion.