Saccharin‐Based Reagents and Catalysts: Expanding the Toolbox of Organic Synthesis

Saccharin, known as the earliest artificial sweetener, has undergone a profound chemical redefinition from a food additive to a versatile molecular platform in modern organic synthesis. Its rigid benzobenzisothiazolone framework, electron‐deficient sulfur (VI) center, and stabilized conjugate base confer unique acidity, leaving‐group capacity, and tunable reactivity. These intrinsic properties have been leveraged to develop a rapidly expanding repertoire of saccharin‐derived reagents and catalytic systems. Recent advances demonstrate saccharin as a privileged synthon and functional‐group transfer platform enabling amination, trifluoromethylthiolation, trifluoromethylselenylation, disulfuration, and acylation under mild and sustainable conditions. Saccharin‐based ion‐pair catalysts have further enabled halide‐ and metal‐free CO 2 activation, while hypervalent iodine (III) reagents and saccharin‐derived zwitterions have opened new avenues for photocatalysis and chemodivergent cross‐couplings. In general, these developments highlight saccharin's emerging role in late‐stage functionalization, medicinal chemistry, and complex molecule construction. This review summarizes recent mechanistic and methodological advances of saccharin‐derived compounds as reagents and catalysts, and outlines future opportunities in chiral reagent design, catalytic asymmetric transformations, and scalable applications.