Computational chemical analysis of Ru(II)-Pheox-catalyzed highly enantioselective intramolecular cyclopropanation reactions.

Computational chemical analysis of Ru(II)-Pheox-catalyzed highly enantioselective intramolecular cyclopropanation reactions was performed using density functional theory (DFT). In this study, cyclopropane ring-fused γ-lactones, which are 5.8 kcal/mol more stable than the corresponding minor enantiomer, are obtained as the major product. The results of the calculations suggest that the enantioselectivity of the Ru(II)-Pheox-catalyzed intramolecular cyclopropanation reaction is affected by the energy differences between the starting structures 5l and 5i. The reaction pathway was found to be a stepwise mechanism that proceeds through the formation of a metallacyclobutane intermediate. This is the first example of a computational chemical analysis of enantioselective control in an intramolecular carbene-transfer reaction using C1 -symmetric catalysts.