Theoretical Approaches to the Conformational Preference of 2,2-Di-tert-Butyl-1,3-Dioxane, 2,2-Di-tert-Butyl-1,3-Dithian, and 2,2-Di-tert-Butyl-1,3-Diselenan

Abstract

This research aimed at exploring the stabilities of 2,2-di-tert-butyl-1,3-dioxane, 2,2-di-tert-butyl-1,3-dithian, and 2,2-di-tert-butyl-1,3-diselenan conformers at the B3LYP/6-311+G(d,p) theory level. To this goal, estimations of the total energies, dipole moments, Frontier Orbital Energies (FOEs), and HOMO/LUMO gaps of the chair and twist-boat conformations were first done for the mentioned molecules. The partitioning of the total electronic energy E(tot) into Lewis E(L) and non-Lewis E(NL) parts was performed using the concept of natural bond orbital (NBO) analysis. Then, the Natural Coulomb Electrostatic (NCE) potential energies, total energies into Lewis components, and total steric exchange energies were estimated. Finally, the hyperconjugative anomeric effects on the conformers were illustrated by NBO analysis and the interactions responsible for the effects were explored.