The α-CH groups of alkyl sulfoxides are susceptible to deprotonation by strong bases, such as sodium hydride:
:CHS(O)CH  +  NaH   →   CHS(O)CHNa  +  H
In the Pummerer rearrangement, alkyl sulfoxides react with acetic anhydride to give migration of the oxygen from sulfur to the adjacent carbon as an acetate ester. The first step of the reaction sequence involves the sulfoxide oxygen acting as a nucleophile: