Conformation and reactivity of some substituted oxan-4-ols in the oxidation with cerium(IV)

Abstract

The kinetics of the oxidation of some substituted oxan-4-ols by cerium(IV) in an aqueous acetic acid medium at 60 °C in the presence of sulphuric acid have been investigated. The reaction is first-order each in oxidant and substrate at constant acid concentration. t-2,t-6-Diphenyl-c-3,c-5-dimethyloxan-r-4-ol, an axial alcohol, reacts slower than the corresponding equatorial epimer, c-2,c-6-diphenyl-t-3,t-5-dimethyloxan-r-4-ol. This anomalous observation and the reactivity of other oxanols towards oxidation have been discussed on the basis of conformational differences.