Computational Study on the Mechanism and Origin of Enantioselectivity in Non-Heme Iron Enzyme-Catalyzed Alkene Trifluoromethyl Azidation

Non-heme iron enzyme-catalyzed enantioselective alkene trifluoromethyl azidation represents a powerful strategy for constructing valuable chiral organofluorine compounds, yet the mechanistic origins of enantioselectivity controlled by the key residues in the enzyme’s chiral environment remain elusive. Herein, we integrate density functional theory (DFT) calculations, classical molecular dynamics (MD) simulations, and quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the mechanism and the origin of enantiocontrol in this transformation. Our computational study reveals that radical addition from the CF3 radical to the 4-methoxystyrene substrate constitutes the enantioselectivity-determining step. The enantioselectivity arises from energetic differences driven by H···H repulsions and C-H···O and N-H···F interactions between the substrate and the binding pocket defined by key residues I335V, F188Q, and R324 near the active site, which stabilize the transition state leading to the major enantiomer. These findings provide mechanistic insights into non-heme iron enzyme-catalyzed asymmetric azido-trifluoromethylation of alkenes and establish a structural framework for rational biocatalyst design.