Sulfonylkloridien

Sulfonylklorider, or sulfonyl chlorides, are a class of organosulfur compounds characterized by the general formula RSO2Cl, where a sulfonyl group is bonded to a chlorine atom. They are typically reactive, moisture‑sensitive electrophiles that hydrolyze in water to sulfonic acids while releasing hydrogen chloride.

Most sulfonyl chlorides are prepared by chlorination of sulfonic acids (RSO3H) using chlorinating agents such as thionyl chloride (SOCl2) or related reagents. Common examples include benzenesulfonyl chloride (PhSO2Cl), p‑toluenesulfonyl chloride (TsCl), and methanesulfonyl chloride (MsCl, also called mesyl chloride). The resulting compounds vary in physical state from liquids to solids and show wide utility in organic synthesis.

In terms of chemistry, sulfonyl chlorides react readily with nucleophiles. Reaction with amines forms sulfonamides (RSO2NR2), a reaction widely used to install sulfonamide protective or pharmacophore groups. Reaction with alcohols yields sulfonate esters (tosylates or mesylates), which can serve as good leaving groups in subsequent substitutions. They are frequently employed to activate alcohols and amines and as protecting groups in multi‑step syntheses.

Applications span pharmaceuticals, agrochemicals, and dyes, with tosyl and mesyl protecting groups playing a central role in synthetic planning. They are valued for the tunable leaving-group properties of the resulting sulfonates and for enabling selective transformations under mild conditions.

Safety considerations include their corrosivity and tendency to release HCl upon hydrolysis. They should be handled under appropriate ventilation, with dry conditions when storage is required, and disposed of according to chemical‑safety guidelines.