The reaction of diphenylphosphine with hexafluoroacetone gives (C6H5)2PC(OH)(CF3)2 which is readily oxidized to (C6H5)2P(O)C(OH)(CF3)2 and, in the presence of base catalyst, undergoes rearrange ment to the isomeric (C6H5)2P(O)OCH(CF3)2. Reaction of hexafluoroacetone with diphenylarsine gives (C6H5)2AsC(OH)(CF3)2 while reaction with diphenyl phosphonate gives (C6H5O)2P(O)C(OH)(CF3)2 which rearranges to (C6H5O)2P(O)OCH(CF3)2.