Understanding the Diverse Reactivity of Pentaphenylborole toward Epoxides

Density
functional theory calculations have been performed to study
the diverse reactivity of pentaphenylborole toward different epoxides.
We systematically investigated the effect of substituents on epoxides
for the preference/competition of three experimentally observed pathways,
that is, intramolecular proton transfer, direct ring expansion via
insertion of one epoxide molecule, and ring expansion via insertion
of two epoxide molecules. Our calculations also predicted a high competitivity
between the proton transfer and direct ring expansion pathways for
the epoxide containing both alkyl and aryl substituents.