Recent Advance on Oxidative the C2-C3 π Bond of Indoles and Its Applications

The oxidative C2-C3 π bond activation strategy is the most efficient tool to synthesize oxygen-containing indoline, which frequently appears in natural products with various biological activities as structural units. Recently, the oxidation-induced cascade strategy through oxygenation activation of the indolic C2-C3 π bond of indoles has received much attention for its use in efficiently establishing complex indoline with oxygen-containing molecular architectures, and holds tremendous potential in the total synthesis of indole alkaloids. It can be carried out using potential activated indole radical cations or imine cation intermediates produced