Metal‐Free Oxidation/C(sp³)H Functionalization of Unactivated Alkynes Using Pyridine‐<i>N</i>‐Oxide as the External Oxidant

Abstract

Externally yours: 2,3-Dihydroquinolin-4(1H)-ones are obtained in moderate to good yields (40–84 %, see scheme) in a metal-free oxidation/C(sp3)H functionalization of unactivated aryl alkynes. 2,6-Dichloropyridine-N-oxide is used as an external oxidant. In the reaction, a Brønsted acid, not a metal, plays a key role in the triple CC bond activation.