Copper-catalyzed oxidative trimerization of indoles by using TEMPO to construct quaternary carbon centers: the synthesis of 2-(1H-indol-3-yl)-2,3′-biindolin-3-ones
Metal-free synthesis of C2-quaternary indolinones by (NH<sub>4</sub>)<sub>2</sub>S<sub>2</sub>O<sub>8</sub> mediated oxidative dearomatization of indoles
An efficient metal-free, (NH4)2S2O8 mediated oxidative dearomatization of indoles for construction of C2-quaternary indolinones was disclosed which provides an approach for generation of all-carbon quaternary centers at the C2 position of indoles.