Oxidative free radical reactions between 2-benzyl-1,4-naphthoquinones and beta -dicarbonyl compounds are described. Electrophilic carbon-centered radicals produced by the manganese(EEL) acetate or cerium(IV) ammonium nitrate oxidation of beta -dicarbonyl compounds undergo efficient addition to a C-C double bond of quinone ring. This free radical reaction provides a novel method for the synthesis of naphthacene-5,12-diones. (C) 2001 Elsevier Science Ltd. All rights reserved.