Facile one-pot preparation of phosphorus ylides from N-amino phthalimide derivatives and their intramolecular Wittig reaction

Crystalline phosphorus ylides were obtained in excellent yield from the 1:1:1 addition reaction between triphenylphosphine, dimethyl acetylenedicarboxylate (DMAD) and N-amino phthalimide derivatives. These phosphorus ylides undergo a smooth intramolecular Wittig reaction in boiling dioxane to produce isoindole rings in good yield.