Synthetic Anthracyclinones. 25. An Improved Route to 8-Demethoxyaranciamycinone and Synthesis of the α-L-Daunosamine Glycosides

Article abstract of DOI:10.1021/jo00194a017

An improved regioselective synthesis for the anthracyclinone precursor 12 is reported using a combination of Diels-Alder and Marschalk reactions.The solvolysis of the benzylic bromides 19/20 with water mainly yields the 7,9-trans-diol 8-demethoxyaranciamycinone (22) whereas the treatment with sodium hydroxide affords the 7,9-cis-diol 21.The α-L-daunosamine glycosides 27-30 are prepared and their absolute configurations are determined by ¹H NMR spectroscopy.