Esters with the general formula R1SO2OR2 are as a category called sulfonic esters, with individual members of the category being named analogously to how ordinary carboxyl esters are named. For example, if the R2 group is a methyl group and the R1 group is a trifluoromethyl group, the resulting compound is methyl trifluoromethanesulfonate.
Sulfonic esters are used as reagents in organic synthesis, chiefly because the RSO2O- group is a good leaving group in Sn1, Sn2, E1 and E2 reactions. Methyl triflate, for example, is a strong methylating reagent. They are commonly used to lend water solubility to protein crosslinkers such as N-hydroxysulfosuccinimide (Sulfo-NHS), BS3, Sulfo-SMCC, etc.
Read more about this topic: Sulfonate