A regiospecific total synthesis on the precursor(18b) of rhodomycinones is described. The anion of 3-carbomethoxy-1(3H)-isobenzofuranone(13) was respectively condensed wi th naphthalenone (12) and butenoate(8) derivatives which were, prepared by two different synthetic routes to afford 9-ethyl-6,7-dihydroxy 7,8,9,10-tetrahydronaphthacene-5,12 dione(18b) after oxidation and reduction.