Abstract
Carboxylic acids react with a mixture of N-chlorosuccinimide, triphenylphosphine and sodium azide at -30°C to form acyl azides in high yields. When two equivalents of triphenylphosphine are applied and the temperature allowed to raise, the reaction yields directly α-carbonyl stabilized iminophosphoranes via Staudinger reaction of the phosphine with the intermediate acyl azide.