Recent Advances in the Multicomponent Reactions of Indoles

Indoles, which are distinguished by their nitrogen-containing heterocyclic structure, play a pivotal role in organic chemistry due to their diverse biological profiles and unique chemical reactivity. In particular, poly-substituted indoles are extensively found in a wide range of natural products, pharmaceuticals, materials, and bioactive compounds. The integration of indoles into multicomponent reactions (MCRs) has emerged as a powerful synthetic strategy, facilitating the construction of these complex poly-substituted indole frameworks from simple precursors. This review highlights the latest advancements in MCRs involving indoles, focusing on innovative methodologies for site-selective synthesis of indole derivatives, catalytic systems, mechanistic insights, and their applications. The review encompasses significant developments from 2014 to 2024 and covers a variety of indole MCRs, including those targeting the C3 position, dual-site reactions at the C2 and C3 positions, and reactions involving the pyrrole and benzene rings of the indole scaffold.