Baeyer-Villiger reaction of steroid sapogenins by CF 3 COOH-H 2 O 2 . A short cut to pregnan-3β,16β,20-triol 3-monoacetates.

Treatment of steroid sapogenins with H2 O2 in CF3 COOH for 15min followed by reflux in CH3 OH/H2 O afforded good yields of pregnan-3β,16β,20-triol 3-monoacetates. When the hydrolysis step was carried out with KOH in refluxing methanol excellent yields pregnantriols were obtained. The resulting compounds were characterized by their melting points and NMR spectral data. An X-ray diffraction analysis of compound 3a confirmed the proposed structure and provided detailed information about the bond lengths, bond angles and conformation.