Sulfonyl units, that is the -SO2- arrangement of atoms, are functional groups that feature in a significant number of pharmaceuticals, argochemcials and materials. Variations in which one or more oxygen atoms of these groups are replaced with nitrogen atoms are also emerging as useful molecules for exploring biological processes. This proposal is focused on this latter class of compounds. The types of molecules this encompasses - primarily sulfoximines and sulfonimidamides - are less explored than then non-aza-equivalent, and this is largely due to the lack of convenient methods for their preparation. Conventional syntheses of these types of molecules usually involve three or four synthetic operations, and often feature low-yielding steps. The chemistry involved also limits the substrates that can be converted to aza-sulfonyl-containing molecules. This proposal seeks to develop new reagents and new reactions to this class of molecules; the proposed chemistry will be achieved in a single operation, employ readily available reagents and substrates, and be conducted under mild conditions. The key aspect of the proposal is the design of new nitrogen-containing reagents that will allow ready access to a little used class of reactive intermediates; sulfinylnitrenes. By delivering these reactive intermediates in a simple way, using readily available reagents, a host of new reactivity, and thus transformations, will be available. These reactions will be used to provide general routes to sulfoximines and sulfonimidamides, as well as primary sulfonamides. We will deliver user-friendly reactions. These transformations will significantly simplify the preparation of these molecules, and allow them to be routinely considered when new collections of molecules for biological evaluation are being designed. We will seek to make the reagents we develop commercially available, thus allowing the rapid take-up of the methods we develop.