[Total synthesis of oxa-9-anthracyclines].

Racemic 7-hydroxy-9-oxa-anthracyclinone (5a) has been synthetised in seven steps from quinizarin (6) and its resolution achieved after glycosylation with 3,4-di-O-acetyl-2-deoxy-L-fucose. Chiral pool syntheses of (8S)-8-hydroxymethyl-9-oxa-anthracyclinone (5b) and of (8S,10R) and (8S,10S)-8-hydroxymethyl-10-methyl-9-oxa-anthracyclinones (5c and 5d) have been achieved using (R)-2,3-O-isopropylideneglyceraldehyde (12) and leucoquinizarin (13) as starting materials. Glycosylation of aglycones 5b-5d by either 3,4-di-O-acetyl-2-deoxy-L-fucose or various 3-amino-2,3,6-trideoxy-L-hexoses yielded the corresponding anthracyclines. The synthetic glycosides do not show significant cytotoxic activity at a concentration of 1 microgram/ml against L 1210 cells.