Synthesis of heterocycles by the aza-Wittig reaction

This review is devoted to the synthesis of N-heterocycles by the interaction of phosphazo groups (either preformed or prepared in situ) with carbonyl or thiocarbonyl groups. Examples are presented systematically for syntheses by an intramolecular aza-Wittig reaction or where the latter is incorporated in a multi-step route. The feasibility of preparing various types of heterocycle by this method has been examined. The bibliography contains 73 references.