RESUMEN
A novel TEMPO/CoCl2-promoted aerobic oxidation of indoles was developed. The reaction provided one-step access to tryptanthrin derivatives in moderate to good yields and excellent regioselectivity via a cascade process. The reactions could be carried out under mild reaction conditions with varying functional group tolerance, especially halogen functional groups. Mechanistic studies disclosed that the oxygen atom in the desired product originated from molecular dioxygen.
RESUMEN
Mild conditions have been developed to achieve NBS-induced homodimerization of indole derivatives with excellent regioselectivity at 15 °C in high efficiency. This method provides a simple route to a 2,3'-linked biindolyl scaffold from the electron-rich to moderately electron-poor indoles. In addition, [3,2-a]carbazole derivatives can also be prepared through this method.