抄録
Regiospecific and effcient synthesis of anthracyclinones have been achieved by using a directed metalation strategy. The phthalides 5a and 5b were prepared by the condensation of metalated N, N-diethylbenzamide derivatives (1') with dihydronaphthalene carbaldehydes (2a and 2b) or by the reaction of metalated dihydronaphthalene (4') with a phthalaldehydic amide derivative (3). The phthalide (5) was then reduced to the acid (14), which was readily cyclized with trifluoroacetic anhydride to the tetracyclic quinone (6). The tetracyclic quinone (6) was converted into the trione (7), a key intermediate for the synthesis of daunomycinone, by epoxidation and subsequent rearrangement using p-toluenesulfonic acid.
