Diphenyliodonium salts in t-butyl alchol have converted the anions of dimedone, dibenzoylmethane and tribenzoylmethane to C-phenyl, C, C-diphenyl, O-phenyl and O, C-diphenyl derivatives, the structures of which have been proved by degradation and synthesis. Reactions of dimedone in methanol or ethanol gave mainly products arising from dehydrogenation of the solvent.