Formal Gold- and Rhodium-Catalyzed Regiodivergent C–H Alkynylation of 2‑Pyridones

Formal regiodivergent C–H alkynylation of 2-pyridones bearing different <i>N</i>-substituents has been realized under Au­(I) and Rh­(III) catalysis using a hypervalent iodine alkyne reagent. When catalyzed by Au­(I), the alkynylation occurred at the most electron-rich 5-position via an electrophilic alkynylation pathway. The selectivity was switched to the 6-position under assistance of an <i>N</i>-chelation group when a Rh­(III) catalyst was employed. A rhodacylic complex has been isolated as a key intermediate