Methyl sulfoxide, caution

Formation of a-Sulfinyl carbanions has been widely investigated17. Several bases were found to be suitable for the generation of these species, e.g., methyllithium and lithium diisopropyl-amide. Butyllithium and rm-butyllithium, however, must be used with caution since they can cause cleavage of the carbon sulfur bond, resulting in an exchange of the ligand at sulfur by a nucleophilic displacement28-29. This method has been used for the preparation of optically active alkyl methyl sulfoxides 28. 

---