Phosphonium Salt-Promoted C2–H Functionalization of Heterocyclic N-Oxides

We report the development of a phosphonium salt as a remarkable activating agent that enables the direct conversion of C2-H bonds of a variety of heterocyclic N-oxides into C2-N, C2-O, or C2-S bonds with high efficiency. The phosphonium salt was prepared on a >150 g scale in a single step and is tolerant of multiple functionalities.