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

Department of Chemistry, Rajah Serfoji Government College, Thanjavur-613 005, India

Department of Chemistry, St. Joseph's College, Trichy-620 002, India

Manuscript received 12 October 1998, revised 5 October 1999, accepted 13 January 2000

Kinetics of oxidation of aromatic acetals by pyridiniumOuorochromate (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 ρ value suggests a mechanism with little charge separation. The rate of oxidation depends on the nature of alkyl group and conformational effects.