Bimetallic Palladium Catalysis: Direct Observation of Pd(III)-Pd(III) Intermediates

Phl(OAc)(2) is a common oxidant for Pd-catalyzed C-H bond functionalizations. Mechanistic hypotheses since the 1960s have suggested a Pd(II)/Pd(IV) mechanism. Here we present evidence for the relevance of bimetallic Pd(III) complexes to catalysis. A bimetallic Pd(III) acetate was isolated and can afford product by bimetallic reductive elimination.