The upsurge of interest in the development of methodologies for the construction of sulfur-containing compounds via the use of expedient reagents has been established as sustainable tools in organic chemistry. This review focuses on the sulfonylation reactions using inorganic sulfites (Na2S2O5 or K2S2O5) as the sulfur dioxide surrogate. Unlike bis-adduct of DABCO, which is an excellent surrogate of the gaseous SO2, the use of sodium or potassium metabisulfites as SO2 surrogates are equally efficient. The objective of the current review is to bring out the latest collection of sulfonylation reactions using inorganic sulfites. For better understanding, the review is categorized according to the mode of reactions viz., transition metal-catalyzed SO2 insertion, metal-free SO2 insertion, and visible light-mediated SO2 insertion. All the reactions in each of the sections are depicted with selected examples with a pertinent explanation of the proposed mechanism. Nevertheless, based on the biological relevance of sulfonylated compounds the use of inorganic sulfites as the SO2 source in various sulfonylation reactions are needed to be explored.
The renaissance of alkali metabisulfites as SO2 surrogate