Recent advances in the oxidative activation of the C2–C3 π bond of indoles and its applications

the oxidative C2-C3 π bond activation of indoles over the past two decades, providing diverse oxygen-containing indolines such as indoxyls, indoline oxygen-heterocycles and indolones. The features and mechanisms of different types of oxidation-induced cascade reactions have been summarized and represented, and examples have been given of their asymmetric reactions and applications in the total synthesis of indole alkaloids.