Synthesis of 3β,6α-dihydroxy-5α-cholan-23-one

Evidence for the presence of 3β,6α-dihydroxy-5α-chol-9(11)-en-23-one in the aglycone mixture from the starfish Marthasterias glacialis is provided by the synthesis of 3β,6α-dihydroxy-5α-cholan-23-one () and its identification in the hydrogenated aglycone mixture. The side-chain is constructed from the 23,24-dinorcholanol () by reaction of the 22-tosylate () with the acetylide anion, followed by hydration of the resulting 23-yne ().