Ruddock, Peter L.; Williams, David J.; Reese, Paul B.
Author Affiliation, Ana.
The scope and limitations of the reaction of D5-steroids with mercury(II) trifluoroacetate
Date of Publication
The effect of C-3 substituent on the reaction of androst-5-enes with mercury(II) trifluoroacetate in dichloromethane (modified Treibs oxidation) was investigated. 3b-Acyloxyandrost-5-en-17-ones gave 3b-acyloxy-6b-hydroxyandrost-4-en-17-ones accompanied by 3b-acyloxy-6-chloromercuriandrost-5-en-17ones. 3b-Acetoxy-6b-trifluoroacetoxyandrost-4-en-17-one and 3b-acetoxy-4b-trifluoroacetoxyandrost-5-en-17-one were revealed to be intermediates in the reaction. The formation of the chloromercury steroids indicated participation in the reaction by the solvent. With 3a-acetoxyandrost-5-en-17-one as substrate, a complete reversal in the product distribution was observed. 3b-Haloandrost-5-en-17-ones gave mainly products that reflected SN1subsitution of the halide. 3b-Hydroxy- and 3b-trifluoroacetoxyandrost-5-en-17ones were formed. 3b-Methoxyandrost-5-en-17-one afforded in nearly identical yields androst-4-ene-3,17-dione, 3b-methoxy-6b-hydroxyandrost-4-en-17-one, 3b-methoxy-6-chloromercuriandrost-5-en-17-one and 6b-hydroxyandrost-4-ene-3,17-dione while androst-5-en-17-one yeilded 3b,6b-dihydroxyandrost-4-en-17-one, androst-5-ene-7,17-dione and androst-4-ene-3,17-dione. The effects of solvent and other mercury salts on the reaction were also studied. Treibs oxidation was successful in chloroform, carbon tetrachloride, and dibromomethane, but not in other solvents tested. 3b-Acetoxy-6-bromomercuriandrost-5-en-17-one was obtained in dibromomethane. Replacement of the reagent by mercury(II) trichloroacetate altered the intermediates formed but not the products. Mercury(II) tribromoacetate was unreactive, however.....