New approach to the aromatization of ring B in 19-norsteroids and to the synthesis of equilenin-type compounds

Abstract

When 7α-acetoxy-3,3 : 17,17-bis(ethylenedioxy)-5,10-epoxy-5β,10β-oestran-6-one (2), formed by lead tetra-acetate acetoxylation of the parent compound (1), is heated with alkali, it undergoes ring B aromatization to give 3,3: 17,17-bis(ethylenedioxy)-5(10),6,8-oestratriene-6,7-diol (3), without configurational change at C(14); deacetalization of the corresponding diacetate (4), followed by lead tetra-acetate aromatization of ring A in the resulting diketone (5), produces 6,7-diacetoxy-equilenin (6), which is finally converted into its 3-acetate (7).