Phosphonation of aryloxyphosphazenes

Two methods for the addition of pendent dialkyl phosphonate units onto aryl oxyphosphazenes, at both the polymeric and cyclic trimer levels, are descri bed. Sodium organophosphites or halogenated organophosphates were used as t he phosphonating agents and were allowed to react with bromomethylene- or l ithio-functionalized aryloxyphosphazenes, respectively. Phosphonation of br omo-methylene-phenoxy side groups proceeded with similar to 100% conversion , while phosphonation via lithiophenoxy intermediates yielded 80-85% conver sion. The presence of a direct phosphorus-carbon bond in all products was c onfirmed by C-13 NMR. Well-defined, cyclic trimers and polymers were obtain ed via both methods.