Being mono-aza analogues of sulfoxides and sulfones, sulfimides and sulfoximines, respectively, are important compounds in asymmetric synthesis, crop protection and medicinal chemistry. For their preparation various methods have been developed. In the search for the optimal synthetic approach for a given target compound, several parameters have to be considered which also include safety issues and availability of starting materials. In this tutorial review, we present an overview of sulfur imidation methods, classified by imidating agents and compounds with a related behaviour. The aim of this survey is to provide a practical ''tool box'' for the synthetic chemist by mapping the advantages and disadvantages associated with the use of these compounds.
Key learning points(1) Most imidating agents consist of the nitrogen atom to be transferred linked to a core fragment and a leaving group. (2) Sulfur imidation involves either the reaction between an electrophilic sulfonium salt and a nucleophilic nitrogen, or the addition of an electrophilic nitren(oid) species to a nucleophilic sulfur. (3) Toxicity and safety issues should be considered before choosing an imidation procedure. (4) Use of a catalytic amount of transition metal can considerably improve the imidation efficiency and allows stereoselective syntheses of sulfimides and sulfoximines.