Oxidation of Natural Targets by Dioxiranes. 6. On the Direct Regio- and Siteselective Oxyfunctionalization of Estrone and of 5alpha-Androstane Steroid Derivatives

Using methyl(trifluoromethyl)dioxirane (1b), 3beta,6alpha,17beta-triacetoxy-5alpha-androstane (6) could be selectively transformed into its C-14 hydroxy derivative (7) and into the valuable C-12 ketone steroid (8), in high yields under mild reaction conditions. Similarly, the oxidation of 3alpha-estrone acetate (4) with 1b was carried out to yield selectively the steroid C-9 hydroxy derivative (5). The high regio- and site- selectivity attained demonstrates that the powerful dioxirane 1b is the reagent of choice to synthesize valuable oxyfunctionalized steroid derivatives