Conformational and steric effects on the oxidation of some cyclic ketones by pyridinium fluorochromate

摘要

The kinetics of oxidation of cyclohexanone, cyclopentanone, cycloheptanone, cyclooctanone and various alpha substituted cyclohexanones by pyridinium fluorochromate(PFC) has been followed under pseudo-first order conditions in aqueous acetic acid medium in the presence of HC1O_4. The reaction is first order both in oxidant and substrate. The rate increases linearly with increasing [HCIO_4]. The salt and solvent influences together indicate the reaction to be an ion-dipole type. The stoichiometry between the substrate and oxidant is 1:2 and the product of oxidation is 1,2-diketone. The relative reactivities of various cyclic ketones have been rationalised on the basis of conformational differentces and steric factors.