Oxidation of Benzylic and Allylic Alcohols with Cobalt(III) Acetate in Acetic Acid in the Presence and Absence of Sodium Bromide

Benzyl alcohol and its o-, m-, and p-substituted derivatives afforded fairly good yields of the corresponding benzaldehydes through a reaction with a Co(III)–NaBr system. With allylic alcohols, this system failed in a selective formation of unsaturated carbonyl compounds. In the latter cases, the products were effectively obtained by using a higher concentration of cobalt(III) acetate in the absence of NaBr.