Electrophilic aminating reagents rely on the presence of an electron-withdrawing functional group attached to nitrogen. A variety of hydroxylamine derivatives have been used for this purpose. Sulfonylhydroxylamines are able to aminate a wide array of carbanions.
Azo compounds afford hydrazines after addition to the N=N bond. These additions have been rendered enantioselective through the use of chiral auxiliaries (see above) and chiral catalysts. Although the enantioselectivity of the proline-catalyzed process is good, yields are low and reaction times are long.
Upon treatment with sulfonyl azides, a variety of Grignard reagents or enolates may be converted into azides or amines. A significant side reaction that occurs under these conditions is the diazo transfer reaction: instead of fragmenting into an azide and sulfinic acid, the intermediate triazene salt may break down to a diazo compound and sulfonamide. Changing workup conditions may favor one product over another. In general, for reactions of enolates substituted with Evans oxazolidinones, trifluoroacetic acid promotes diazo transfer while acetic acid encourages azidation (the reasons for this are unclear). Solvent and the enolate counterion also influence the observed ratio of diazo to azide products.
Other electrophilic aminating reagents include oxaziridines, diazo compounds, and in rare cases, imines.