Tosyl group

The tosyl terminology was proposed by German chemists Kurt Hess and Robert Pfleger in 1933 on the pattern of trityl[1] and adopted in English starting from 1934.

In this reaction, the lone pair of the alcohol oxygen attacks the sulfur of the tosyl chloride, displacing the chloride and forming the tosylate with retention of reactant stereochemistry.

The use of these functional groups is exemplified in organic synthesis of the drug tolterodine, wherein one of the steps a phenol group is protected as its tosylate and the primary alcohol as its nosylate.

It can be deprotected to reveal the amine using reductive or strongly acidic conditions.

Closely related to the tosylates are the nosylates and brosylates, which are the abbreviated names for o- or p-nitrobenzenesulfonates and p-bromobenzenesulfonates, respectively.