·~--------------------

Sorbic acid precursors have been obtained in larger scale and high current efficiency by a Mn(III)-mediated oxidation of acetic acid-acetic anhydride in the presence of butadienc. Cu(II) enhances the efficiency of this oxidation to isomeric acetoxyhexenoic acids. The reaction involves addition of the methylhydroxycarbonyl radical, generated by Mn(III) from acetic acid, to butadiene, further oxidation of the allyl radical by Cu(II) to the ally! cation, and subsequent acetolysis [225c].