"Alkenes possessing allylic C-H bonds are oxidized by SeO2 either to allylic alcohols or esters or to α,β-unsaturated aldehydes or ketones, depending on the experimental conditions. … Reaction of chromic anhydride (CrO2) with t-butanol yields t-butyl hydrogen chro- mate, a powerful oxidant suitable for allylic oxidation of electron-deficient alkenene. Copper(I) salts catalyze thc allylic oxidation of alkenes in the presence of peresters, such as tert-BuO2COPh, to afford the corresponding allylic benzoate esters."