Impact of Precatalyst Activation on Suzuki-Miyaura Catalyst-Transfer Polymerizations: New Mechanistic Scenarios for Pre-transmetalation Events

The relevance of L_nPdX₂ precatalyst activation on the Suzuki-Miyaura reaction course was investigated in the case of catalyst-transfer polymerizations. A catalytic study, backed up by theoretical calculations, allowed to ascertain the coexistence of a neutral and an anionic mechanistic pathways in the precatalyst activation, in which the bulky ^tBu₃P external ligand plays a crucial role. The fine-tuning of the catalytic conditions can steer the activation step toward the anionic pathway, leading to the full control over the polymerization course. While providing insights and perspectives into the catalyst-transfer polymerizations, these results uncover unexplored scenarios for the pre-transmetalation events of Suzuki-Miyaura reactions contributing to its full understanding.