A mathematical expression for the enantioselectivity and thermodynamic factors in the conformational equilibrium of catalysts in the addition of diethylzinc to benzaldehyde

A mathematical expression for the enantioselectivity and thermodynamic factors is presented in the conformational equilibrium of a flexible chiral catalyst for the asymmetric addition of diethylzinc to aldehydes. The results show that the total enantioselectivity of the catalyzed reaction is not only governed by the free energy difference of two ground-state conformers, as well as the free energies of activation for the major enantiomeric product formed from each of the catalyst’s conformations, but also by the difference in the transition state energies of the formation of the (S)- and (R)-enantiomers from the individual conformers of the catalyst.

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