Recent Advances in Indole Synthesis and the Related Alkylation

The derivatives of indoles are very useful intermediates in pharmaceuticals and organic synthesis. The efficient synthesis of the indole blocks and related functionalizations, especially the alkylation of indoles are hot topics in recent years. This review will focus on the following two aspects: i) new developments for the synthesis of indoles which was catalyzed by transition metals, the alkylation of indoles, including the one on N₁‐position, C₂‐position, as well as C₃‐position. 1. Introduction 2. Synthesis of indoles catalyzed by various metals 2.1. Synthesis of indoles by palladium catalysts 2.2. Synthesis of indoles by other metal catalysts 3. Alkylation of indoles 3.1. N₁‐alkylation of indoles 3.2. C₂‐alkylation of indoles 3.3. C₃‐alkylation of indoles