In this work, the reactions of diphenylphosphinic chloride, (C 6 H 5 ) 2 P(O)Cl, 1, with the sodium salts of sterically hindered phenol derivatives (2a-2j) were investigated. Novel alkyl-substituted aryl diphenyl phosphinate esters (C 6 H 5 ) 2 P(O)OAr (3-12) were obtained from these reactions. Satisfactory analytical and spectroscopic results were obtained for all the new compounds.