Abstract: The stable conformations of aromatic compounds constitute fundamental contents in teaching organic chemistry. They play a crucial role to discuss and to identify acidity/basicity and reactive activity in the aromatic electrophilic substitution of these compounds. Current textbooks inadequately explain the variation in stable conformations of different aromatic compounds and their underlying causes. This study systematically examines several representative aromatic compounds, including phenol, anisole, aniline, and trifluoromethylbenzene, by analyzing the relative strengths of their n-π₆⁶ conjugation and n-σ^* hyperconjugation, as well as the involvement of hydrogen-bonding interactions. Through comprehensive evaluation of these electronic effects and intermolecular interactions, we elucidate the formations preferences and rationale their formation origins in these aromatic systems.

Key words: Phenol, Aniline, Anisole, (Trifluoromethoxy) benzene, Stable conformation, Hyperconjugation effect