An improved synthesis of bis(cyclopentadienone)

An improved strategy for the synthesis of 3,3′-(oxy-p-phenylene)bis(2,4,5-triphenylcyclopentadienone) was developed, which includes three steps: Friedel–Crafts reaction, oxidation and condensation. Importantly, the use of KMnO4 made the second step simple and efficient, which has potential application to synthesis of bis(cyclopentadienone)s. The course of oxidation has been confirmed by isolated intermediates.