Total syntheses of (.+-.)-duanomycinone. Regiospecific preparations of (.+-.)-7,9-dideoxydaunomycinone and 6,11-dihydroxy-4-methoxy-7,8,9,10-tetrahydronaphthacene-5,9,12-trione
Total syntheses of (.+-.)-duanomycinone. Regiospecific preparations of (.+-.)-7,9-dideoxydaunomycinone and 6,11-dihydroxy-4-methoxy-7,8,9,10-tetrahydronaphthacene-5,9,12-trione
A new method for the meta acylation of anisole and its para-methyl or fluoro derivatives, is described. Addition of two trimethysilyl groups in the 2 and 5 positions (relative to the methoxy group), followed by hydrolysis affords the corresponding 5-trimethylsilyl-3-Cyclohexenones. Electrophilicsubstitution of the silyl group using RCOCl/2AlCl3 at low temperature provides, after final aromatisation