Progress in the Synthesis of 2,3-Disubstituted Indole by Cyclization

In recent years, there are many reports about the synthesis of 2,3-disubstituted indole by cyclization.Most of these approaches are catalyzed by different transition metals and metal-free catalysis conditions using phenylnydrazines, anilines and nitrobenzenes as main substrates.These methods have been a powerful strategy to obtain 2,3-disubstituted indoles.The recent progress of the synthesis of 2,3-disubstituted indoles by cyclization with the different substrates systems is summarized.