The aluminium chloride catalysed reaction of phosphorus(III) halides and carbonyl compounds. I. Reaction with benzophenone

Abstract

In the presence of partially hydrated aluminium chloride, phenylphosphonous dichloride and diphenylphosphinous chloride add smoothly to benzophenone to give chlorodiphenylmethylphenylphosphinic chloride and benzhydryldiphenylphosphine oxide respectively. Little reaction occurs with anhydrous aluminium chloride, and phosphorus trichloride does not react under any conditions. The factors affecting these reactions are described and possible mechanisms discussed. It is suggested that the intermediacy of species of the type [PhPCl₃]⁺[PhPCl,AlCl₃]^- best explains the observed results.