Metal‐Free Nitration of the C(sp3)−H Bonds of 2‐Oxindoles through Radical Coupling Reaction at Room Temperature

A metal‐free nitration of the C(sp3)−H bonds of 2‐oxindoles with t‐BuONO through radical coupling reaction at room temperature has been developed. Using t‐BuONO both as a nitrating reagent and as an oxidant, to couple with the C(sp3)−H bonds of 2‐oxindoles, thus forming a new C−N bond without using any other reagents. This reaction provides a green and straightforward approach to some useful 3‐nitro‐2‐oxindoles in moderate to good yields.