Aza-Wittig reactions are most commonly used to convert aldehydes and ketones to the corresponding imines.
[1] The conversion has also been practiced in an intramolecular sense, which is commonly used in the synthesis of N-heterocyclic compounds.
[1] In some cases, the iminophosphorane is not isolated but generated in situ.
In this manifestation, the phosphine, carbonyl, and organic azide are combined Besides preparing imines from aldehydes and ketones, the aza-Wittig-reaction can also convert carbon dioxide to isocyanates, carbon disulfide to organic thiocyanates, and isocyanates to carbodiimides.
Such an issue is mitigated via catalytic aza-Wittig-reactions, some of which entail elements other than phosphorus, like arsenic and tellurium[5][6].The reagent for the aza-Wittig reaction, iminophosphorane, was discovered in 1919 by Hermann Staudinger.