Palladium‐Catalyzed Phosphonation of Polyphenylsulfone

An efficient synthetic procedure for the phosphonation of aromatic polymers was developed and is here exemplified for polyphenylsulfone. This procedure involved the bromination of the polymer and the subsequent bromine‐phosphorus exchange by means of a Pd(0)‐catalyzed PC coupling reaction. In the resulting product, the phosphonate ester pendant groups were attached to aromatic rings of the polymer chain without alkylene spacer units. A substitution degree of almost one phosphonate moiety per repeating unit of the polymer was achieved in the presence of Pd2(dba)3 · CHCl3 as catalyst at 120 °C. Polymers with free phosphonic acid groups were prepared by ester hydrolysis. magnified image