Frontier molecular orbital effects control the hole-catalyzed racemization of atropisomeric biaryls.

ABSTRACT: Atropisomeric biaryl systems are privileged architectures used in asymmetric synthesis and pharmaceutical structures. We report that by simply removing a single-electron, the resistance of biaryls towards racemization is reduced dramatically. Even though the steric properties are unaltered, biaryl oxidation changes atropisomerization into a two step mechanism with considerably smaller activation barriers than closed-shell biaryls. The effect is general for a series of biaryls and helicenes studied and results from the dependence of frontier molecular orbital energies on biaryl conformation.

SUBMITTER: Tan JSJ 

PROVIDER: S-EPMC6399675 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature