Oxidation of natural targets by dioxiranes.: Part 6:: on the direct regio- and site-selective oxyfunctionalization of estrone and of 5α-androstane steroid derivatives

Using methyl](trifluoromethyl)dioxirane (1b), 3 beta,6 alpha,17 beta-triacetoxy-5 alpha-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 3 alpha-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. (C) 2008 Elsevier Ltd. All rights reserved.