Intramolecular Acylation of Aryl- and Aroyl-Aliphatic Acids by the Action of Pyrophosphoryl Chloride and Phosphorus Oxychloride

Both pyrophosphoryl chloride and phosphorus oxychloride react with aryl aliphatic acids to form mixed anhydrides which undergo intramolecular acylation to afford cyclic ketones without the addition of a Friedel-Crafts catalyst. Aryl and aroylbenzoic acids could be cyclized to the corresponding anthrones and anthraquinones respectively.