Coupling of 1-amino-2-hexanone (I) with 1-bromocyclopropanecarboxylic acid (II) produces keto amide (III). Subsequent cyclization of (III) under acidic conditions leads to oxazole (IV) .

The 9,10-seco-steroid (V) is photochemically isomerized to (VI) under irradiation of a mercury lamp. Subsequent reduction of the methoxyamide function of (VI) employing DIBAL provides aldehyde (VII). Lithiation of the bromocyclopropane derivative (IV), followed by addition to aldehyde (VII) leads to carbinol (VIII) as a mixture of diastereoisomers. After chromatographic separation, the desired isomer is desilylated with tetrabutylammonium fluoride to furnish the title compound.