CONFORMATIONAL AND STERIC EFFECTS ON THE OXIDATION OF SOME CYCLIC-KETONES BY PYRIDINIUM FLUOROCHROMATE

The kinetics of oxidation of cyclohexanone, cyclopentanone, cyclohepta none, cyclooctanone and various alpha substituted cyclohexanones by py ridinium fluorochromate(PFC) has been followed under pseudo-first orde r conditions in aqueous acetic acid medium in the presence of HClO4. T he reaction is first order both in oxidant and substrate. The rate inc reases linearly with increasing [HClO4]. The salt and solvent influenc es together indicate the reaction to be an ion-dipole type. The stoich iometry between the substrate and oxidant is 1:2 and the product of ox idation is 1,2-diketone. The relative reactivities of various cycle ke tones have been rationalised on the basis of conformational difference s and steric factors.