Recent advances in aza-Wittig reaction, including intermolecular, intramolecular and tandem ones, are reviewed. The application of the aza-Wittig reactions in synthesis of some N-heterocycles, fused heterocycles and natural products are also discussed. Some N- containing compounds not easily accessible by other methods were prepared by intermolecular aza-Wittig reactions under mild neutral conditions. The effcient intramolecular aza-Wittig reaction was also successively utilized in synthesis of five to eight-membered heterocycles, including some optically active natural compounds. Many heterocycles, fused heterocycles and natural compounds were prepared via the versatile tandem aza-Wittig reaction, such as tandem aza- Wittig/heterocumulene- mediated annulation, three component tandem aza- Wittig reaction, tandem aza-Wittig/electrocyclic ring closure, tandem aza-Wittig/ hetero-Diels-Alder closure and tandem aza-Wittig reaction utilizing bis-iminophosphorane.

Key words: ORGANIC SYNTHESIS, WITTIG REACTION, FUSED RING COMPOUNDS, NITROGEN HETEROCYCLICS, INTERNAL MOLECULAR REACTION