DFT Study of the Strong Solvent Effects in the Cu-Catalyzed Asymmetric Conjugate Addition Reaction

Significant solvent effects on enantioselection exist in the reaction of Cu-catalyzed asymmetric conjugate addition of alkylzinc reagents to alpha,beta-unsaturated carbonyl compounds. Results of our DFT study suggest that solvent effects on enantioselection can be caused by structural changes in the stereodetermining Transition States (TS). We have seen how unconventional hydrogen bonding of the nucleophilic solvent results in a change of the computed optical yield comparable to that caused by well-known coordination of the solvent to the electrophilic metal center.