Participation of Carbonyl Oxygen in Carbon-Carboxylate Bond-Forming Reductive Elimination from Palladium

This paper describes density functional theory (DFT) calculations of the mechanism of carbon-acetate bond-forming reductive elimination from Pd centers. This C-O coupling reaction has been studied at a series of different Pd-IV, Pd-III, and Pd-II complexes. In all cases, three-membered transition states involving direct coupling of the Pd-bound O and C atoms have been compared to five-membered transition states where the pendant carbonyl oxygen participates in the C-O coupling event. These calculations show that the five-membered transition state is kinetically favored by between 4.7 and 13.2 kcal/mol.