Methanesulfonyl chloride (MSC) is very reactive towards alcohols (methanesulfonates), amines (sulfonamide groups).

The newly formed methanesulfonate maintains the same stereochemistry of the original alcohol and it is more reactive with nucleophile molecules; very useful, for example, in carbohydrates synthesis.

The sulfamide group can be used to increase the acidity of the original amine and unlock a different reactivity.
In addition, it can also be used as a carboxylic acid activating agent, in the synthesis involving inversion of lactones, cycloadditions and in the preparation of boronic esters.

Methanesulfonates are often employed in substitution, reduction and elimination reactions.