How Silver Additives Promote Copper-Catalyzed Cyclization and Alkene Transposition: A Mechanistic Study

Cu-catalyzed alkene transposition/cyclization of alkenols efficiently constructs spirocyclic ethers; however, the precise function of Ag additives remains elusive. In this study, density functional theory (DFT) calculations reveal that Ag constructs a stable, multidentate coordination framework that facilitates synergistic catalysis. Detailed quantum theory of atoms in molecules (QTAIM) analyses reveal that Ag···C, Ag···O, Ag···H, and Ag···Cu interactions are pivotal to the stabilization of the key hydrogen transfer process. Complementary energy decomposition analysis (EDA) ascribes this stabilization primarily to the synergy of orbital, electrostatic, and dispersion interactions, providing a quantitative rationale for the observed bimetallic effect.