Bromide‐Catalyzed Site‐Selective C–H Selenylation of Pyridones With Se Powder and Boronic Acids

Herein, a metal‐free and general platform for the direct (di‐ or mono‐)selenylation at the C3 and C5 position of pyridones via bromide catalysis, using Se powder and boronic acids as the selenyl precursors, was successfully disclosed. This strategy proceeded with high site‐selectivity under the directing group‐free and transition‐metal‐free conditions. Simple catalytic system, high efficiency, operational simplicity, excellent functional group tolerance, strong chemical‐oxidant free, and easily scale‐up, were shown in this method. Furthermore, the mechanistic experiments indicated that a radical pathway was possibly involved.