A convenient and novel method of cyclisation of 4-(4-substituted-phenylsulfonamido)-butanoic acids to their corresponding p-substituted 1-arylsulfonyl-pyrrolidin-2-ones was achieved by using polyphosphate ester (PPE). The reaction times were considerably reduced, with an increase in yields, when PPE was used in combination with a catalytic amount of pyridine.
