Cascade cyclization of alkyne-based Ugi adducts towards N-heterocycles

The Ugi-four component reaction is a powerful tool to form multifunctionalized Ugi adducts due to its high variability, notable atom economy and mild reaction conditions. Moreover, the functional groups allow further transformation into complex compounds, which have been widely used in medicinal chemistry, drug discovery, material science and natural products. Recently, cascade cyclization of alkyne-based Ugi adducts giving access to various N-heterocycles have attracted significant attention. This review covers the recent cascade strategies starting from 2018 of alkyne-based Ugi adducts for the synthesis of various N-heterocyclic frameworks via the tandem formation of new C-C/C-N/C-O bonds under transition metal catalysis and under metal-free conditions. Diverse types of cyclizations are highlighted. © 2025 Elsevier B.V., All rights reserved.