Unsymmetrical Diarylketones from Electron-rich Heterocyclic Arenes

Summary.

 AlCl₃-mediated chlorocarbonylation of a first arene by oxalyl chloride followed by in situ Friedel-Crafts acylation of a second electron-rich arene expeditiously provides, in a one-pot procedure, either symmetrical or unsymmetrical benzophenones with yields ranging from 17–52%. Best results are obtained when the more activated substrate is used as the second arene. Another advantage is that the resultant benzophenone precipitates from the reaction mixture allowing facile workup.