Synthesis of the marine epoxy sterol 9α,11α-epoxy-5α-cholest-7-ene-3β,5,6β-triol

Article abstract of DOI:10.1016/0039-128X(91)90066-5

The synthesis of 9α,11α-epoxy-5α-cholt'st-7-ene-3β,5,6β-triol (1), a highly oxygenated marine sterol containing a 9,11-epoxide moiety in the nucleus, is described. Epoxy sterol 1 was synthesized from cholesta-5,7-dien-3β-ol. Oxidation of this sterol with m-chloroperbenzoic acid followed by hydrolysis and acetylotion furnished 5α-cholest-7-ene-3β,5,6α-triol 3,6-diacetate (2). Mercuric acetate dehydrogenation of diacetate 2, followed by oxidation with manganese dioxide and epoxidation with m-chloroperbenzoic acid, afforded 9α,11α-epoxy-3β,5-dihydroxy-5α-cholest-7-en-6-one (5). Reduction of 5 with lithium aluminum hydride gave the desired compound 1. The structures of all synthetic intermediates were confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. A reassignment of resonances for carbons 1, 8, and 15 in the ¹³C NMR spectrum of 1, based on 2D-NMR correlation spectroscopy, has been accomplished.