Abstract: As a fundamental framework for elucidating the structure and reactivity of organic molecules, molecular orbital theory remains underutilized in systematic classroom applications despite its introductory coverage in chemical principles courses. This pedagogical gap often results in students memorizing reaction patterns without comprehending their underlying principles. Adopting a molecular orbital approach, this study examines how integrating representative organic reaction examples can facilitate deeper mechanistic understanding. Beginning with the precise interpretation of mechanistic arrows, we progressively explore comparative nucleophilic substitution rates, stereochemical effects (including Baeyer-Villiger migration preferences), and substitution-elimination chemoselectivity, thereby demonstrating the unifying power and didactic value of molecular orbital theory. Teaching implementations reveal that this approach not only strengthens conceptual mastery but also stimulates students’ intrinsic curiosity for mechanistic exploration.

Key words: Organic chemistry, Molecular orbital, Teaching innovation, Reaction mechanism, Stereochemistry