Hyperconjugative Electron-Delocalization Mechanism Controlling the Conformational Preference of Fluoroacetaldehyde and Methyl Fluoroacetate

We confirmed by both canonical molecular orbital analysis and the orbital deletion procedure (ODP) that a hyperconjugative electron-delocalization mechanism is the main factor controlling the conformational preference for cis and trans conformations of fluoroacetaldehyde (FAA) and methyl fluoroacetate (MFA). The quantitative analysis based on the ODP approach shows that the effects of hyperconjugation are more important in the cis conformation than in trans conformation.