abstract |
Preparation of DELTA4-6alpha-fluoro-steroids by reacting a DELTA5-3-hydroxy-steroid with anhydrous HF in the presence of a metallic reagent from lead tetraacetate, lead dioxide, osmium tetroxide and cobaltic oxide, after which the 3-hydroxy is oxidised to 3-keto and the compound treated with an acid or a base to afford the DELTA4-3-keto-6alpha-fluoro compound. |