Crystalline phosphorus ylides are obtained in excellent yields from the 1: 1: 1 addition reaction between triphenylphosphine, dimethyl acetylenedicarboxylate and aromatic amines, such as aniline, 1-naphthylamine, p-toluidine, 4-bromoaniline, 4-nitroaniline, 4- acetylaniline, 2-aminopyridine, or 2-amino-5-bromopyridine. These stabilized phosphoranes undergo a smooth intramolecular reaction in boiling p-xylene or toluene to produce ...