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(sp(3))-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(sp(3))-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.