Computational study on the substrate-controlled selectivity of Ru-catalyzed ring-closing metathesis.

Dienes are classic substrates for ring-closing metathesis and hold significant synthetic value in the construction of cyclic compound skeletons. In this study, density functional theory (DFT) is employed to calculate the reaction mechanisms of Ru-catalyzed ring-closing metathesis for aza-diene or oxa-diene substrates. The origin of the reaction selectivity is systematically elucidated through structural analysis, electronic effects, and EDA analysis. The computational results suggest that the rate-determining transition state ts4-N along the reaction pathway of aza-diene substrates exhibits a more favorable planar conformation and stronger electrostatic interactions than ts4-O for the oxa-diene substrates, which further promotes the generation of ring-closing products.