P. Magnus et al., A CONCISE SYNTHESIS OF THE ANTHRAQUINONE PORTION OF DYNEMICIN-A, Journal of the Chemical Society, Chemical Communications, (13), 1994, pp. 1545-1546
Addition of the lactone anion derived from 29 to 13 gave the adduct 30
, which was dehydrated to give 20; subsequent conversion of 20 into th
e anthraquinone 26 was achieved in two steps.