Synthesis of Carbazole-1&3-Acids by using Suzuki Coupling followed by Cadagon Reductive Cyclization

Using a Suzuki coupling followed by Cadagon reductive cyclization as a key steps, the first synthesis of 1-carboxylic acid carbazole has been achieved in 4 steps and in 65% overall yield. In the present work, this approach was applied to the total synthesis of carbazole alkaloids. This is the simple way to synthesise 9H-Carbazole-1-carboxylic acid and 9H-Carbazole-2-carboxylic acid.