REACTIVITY OF 5,10-8,14-DISECOSTEROIDS - AN UNUSUAL REARRANGEMENT OF CYCLODECENE-1,4-DIONE SYSTEMS TO 5-MEMBERED-RING SPIRO-GAMMA-LACTONES

Upon heating in AcOH, the stereoisomeric (Z)- and (R)-6,9-dioxocyclode x-3-enyl derivatives, 5 and 6, respectively, obtained by HgO/I-2 oxida tion of 5-hydroxy-8-oxo-8,14-seco-5 alpha-androstane-3 beta,17 beta-di yl diacetate (3), undergo an unusual intramolecular rearrangement to g ive the corresponding unsaturated (5R,9R)- and (5R,9S)-spiro-lactones 7 and 8, respectively. Hydroxylation of the C=C bond in 7 and 8, and s ubsequent glycol cleavage of the resulting diols 9 and 10 afforded the epimeric spiro-lactones (5R,9S)-11 and (5R,9R)-14, respectively,and i n both cases, the ring-D-containing fragments 12 and 13.