Sulfonyl azides in multicomponent and cascade strategies for synthesizing heterocycle and non-heterocyclic scaffolds

Sulfonyl azides have emerged as remarkably versatile reagents in contemporary synthetic chemistry, functioning both as azide-transfer agents and as precursors to N-sulfonylketenimines and nitrenes that enable a broad array of bond-forming events. This review systematically summarizes recent advances in the utilization of sulfonyl azide derivatives within multicomponent, cascade, and tandem protocols for constructing heterocyclic and non-heterocyclic frameworks. Emphasis is placed on mechanistic manifolds—such as Cu-catalyzed azide–alkyne cycloaddition (CuAAC) followed by ketenimine formation, nitrene insertion, and radical or ketenimine interception—that underpin the efficient synthesis of indolines, furans, pyrazoles, pyrimidines, azetidines, quinazolines, pyrroles, imidazoles, spirocycles, pyridines and numerous other scaffolds. We critically evaluate substrate scope, electronic/steric effects, catalyst systems (including copper, cobalt, nickel, rhodium, iron and heterogeneous/ nanocatalysts), and practical aspects such as operational simplicity, atom economy and scalability. Limitations—e.g., diminished performance with aliphatic alkynes in certain sequences, sensitivity to strongly electron-withdrawing partners, stereochemical challenges and incomplete mechanistic understanding in select pathways—are highlighted. By consolidating the current state of the art, this review aims to guide practitioners in deploying sulfonyl azides for the rapid, modular assembly of functionally rich molecular scaffolds.