Olefinically unsaturated substituents at C-11 of steroid cyclization precursors

Abstract

Compositions are provided as well as methods for preparing the compositions which serve as cyclization precursors for the preparation of C-11 alkenyl substituted steroids and nor-steroids. The alkenyl group may be converted after cyclization to a variety of heterosubstituents to provide heterofunctionalized C-11 steroids and nor-steroids. The compounds are provided having an initiator group, which has a chalcoxy atom in juxtaposition to a double bond, an olefinically unsaturated linking group and a terminating group which acts to from a carbocation which reacts with a nucleophile to provide a stable product. The C-11 substituent is found to provide upon cyclization the alpha-configuration, so that the subject compounds provide a direct route to the difficultly accessible alpha-C-11 substituted steroids, or, if desired, the alpha-configuration can be inverted to the beta-configuration.

Dependencies are inferred from the claim text.