Synthetic anthracyclinones-XXVII anthracyclinones by intramolecular marschalk reaction : Synthesis of the feudomycinones and rhodomycinones

1,4,5-Trihydroxy-9,10-anthraquinone is transformed regioselectively to the α-hydroxy dichlorides 18-21, which are cyclized to yield predominantely the naturally configurated 9,10-trans-diols 1,3,26, and 27 (80 to 96% d.e.). The monotrifluoroacetates 38-40 derived from the trans-diols are hydroxylated via bromination at C-7 to yield almost exclusively the 7,9-cis-9,10-trans-triols α₁-rhodomycinone (4), feudomycinone D (7), and 4-0-methyl-β-rhodomycinone (42). The feudomycinones A (5) and C (6) are obtained with less chemo- and stereoselectivity by hydroxylation of the l0 Deoxycompounds 33 and 34.