Synthesis and Biological Evaluation of 3,16,20-Polyoxygenated Steroids of Marine Origin and Their Analogs

ABSTRACT The natural polyoxygenated steroids (20S)-20-hydroxycholestane-3,16-dione (1), (16S, 20S)-16,20-dihydroxycholestan-3-one (2), (20S)-20-hydroxycholest-1-ene-3,16-dione (3) and (20S)-20-hydroxycholest-4-ene-3,16-dione (4), isolated from the gorgonian, Leptogorgia sarmentosa and unnatural analogs (5) (6)