Linear free energy relationship and conformational effects on oxidation of aromatic acetals by pyridinium fluorochromate

Kinetics of oxidation of aromatic acetals by pyridiniumfluorochromate (PFC) in aqueous acetic acid medium reveal that the reactions are second order, first order each in [acetal] and [PFC]. The presence of electron-withdrawing substituents in the benzene ring enhances the rate of oxidation while that of opposite one retards it. The small p value suggests a mechanism with little charge separation. The rate of oxidation depends on the nature of alkyl group and conformational effects.