Reconstruction of ring A of 3,4-dinor-2,5-seco steroids

Abstract

Methods for the reconversion of 3,4-dinor-2,5-seco steroids into the parent 4-en-3-one systems are discussed. In an efficient route, reaction of 17β-acetoxy-5,5-ethylenedioxy-3,4-dinor-2,5-secoandros-tan-2-al with ethoxyvinyl-lithium led to the corresponding 2ξ-hydroxy-3-one. Acetylation followed by treatment with zinc dust in acetic acid then gave testosterone acetate. A similar series of reactions was performed in the progesterone series.