A key role for iodobenzene in the direct C–H bond functionalisation of benzoxazoles using PhI(OAc)2 mediated by a Pd(OAc)2/1,10-phenanthroline catalyst system: in situ formation of well-defined Pd nanoparticles

PhI(OAc)2 has previously been reported as a reagent for the direct arylation of C–H bonds in benzoxazole in a PdII/IV-mediated process. However, evidence reported here suggests this reagent degrades to iodobenzene under the literature reported reaction conditions. Further, we present evidence for the rapid formation of Pd0 nanoparticles in this reaction, leading us to question what is the active catalytic Pd phase in coupling chemistry?