Palladium enolate complexes such as (PPh₃)₂PdX(CH₂COPh) (1) are potential intermediates for coupling reactions in which a new bond is formed between an enolate alpha carbon and an sp or sp² carbon via transmetallation.  However, at the elevated temperatures often required for these coupling reactions, (PPh₃)₂PdX(CH₂COPh) [X = Cl, Br] loses the acetophenone enolate ligand and releases CH₃COPh, (PPh₃)₂PdX₂, and three other Pd species, one of which has alkene H's typical of an O-bound enolate.  The observed first order rate constant for enolate loss from (PPh₃)₂PdBr(CH₂COPh) is 8.6 x 10^-5 s^-1 at 65° C in tetrachloroethane-d₂; the analogous rate constant for enolate loss from (PPh₃)₂PdCl(CH₂COPh) is 4.3 x 10^-5 s^-1.  A first order process that is dependent upon the halide ligand could involve rate limiting enolate dissociation from Pd; a second possibility is a rapid equilibrium that forms (PPh₃)₂Pd(CH₂COPh)₂ (2) followed by rate-limiting intramolecular C-H activation to protonate one of the enolate ligands of 2 and release CH₃COPh.  To probe for C-H activation, (PPh₃)₂PdBr(CH₂COPh-d₅) was heated at 65° C in tetrachloroethane and produced CH₃COPh with 30% D at the alpha carbon, indicating that enolate phenyl Csp²-H activation is responsible for a significant fraction of the observed acetophenone.