Stereochemical Interrelationship between Maridomycin and Leucomycin

Abstract

Epoxidation of 18-dihydroleucomycin A_s (5) with m-chloroperbenzoic acid afforded 18-dihydromaridomycin II (6). Conversion of leucomycin A_s (1) into maridomycin II (2) was also accomplished in a similar process. This evidence together with the result of X-ray analysis of 9-propionylmaridomycin III has finally confirmed the absolute stereochemistry of leucomycin A_s. In addition, Δ²-9-epi-18-dihydromaridomycin III (12) was prepared by the NaBH₄ reduction of 9-dehydromaridomycin III (11) and the effect of the C-9 hydroxyl group on optical rotations was discussed.