Prasterone (I) was protected as the silyl ether (II) upon treatment with tert-butyldimethylsilyl chloride and pyridine, and its ketone group was then reduced to alcohol (III) with NaBH4 in Et2O-EtOH. Hydroboration of the olefinic double bond of (III), followed by oxidative treatment with sodium perborate yielded the dihydroxy steroid (IV), which was protected as the diacetate (V) by esterification with Ac2O in pyridine. The silyl ether group of (V) was subsequently removed by treatment with tetrabutylammonium fluoride in THF, and the deprotected 3-b alcohol (VI) was oxidized to ketone (VIII) with 2-iodoxybenzoic acid (VII) in DMSO. Saponification of the acetate esters of (VIII) with NaOH in aqueous MeOH furnished the dihydroxyandrostanone (IX). Then, reaction of the ketone group of (IX) with O-(2-aminoethyl)hydroxylamine-2HCl (X) gave oxime (XI). Finally, oxidation of the remaining hydroxyl groups of (XI) with 2-iodoxybenzoic acid (VII) afforded the title androstanedione.