Computational Investigation on the Origin of Atroposelectivity for the Cinchona Alkaloid Primary Amine-Catalyzed Vinylogous Desymmetrization of -(2--Butylphenyl)maleimides.

Mechanistic studies clarifying how chiral primary amines control the stereochemistry of vinylogous processes are rare. We report a density functional theory (DFT) computational study for the comprehension of the reaction mechanism of the vinylogous atroposelective desymmetrization of -(2--butylaryl)maleimide catalyzed by 9-amino(9-deoxy)epi-quinine. Our results illustrate how the origin of the atroposelectivity was realized by the catalyst through steric and dispersion interactions. The role of -Boc-l-Ph-glycine was crucial for the formation of a closed transition-state geometry and the activation of both reaction partners.