Synthese von 18‐Carboxy‐steroiden. Über Steroide, 146. Mitteilung

A number of intermediates for a synthesis of aldosterone have been prepared from the known d,l‐δ8a‐1‐oxo‐4β‐hydroxy‐4bβ‐methyl‐7‐ethylenedioxy‐4aα, 10aβ‐dodecahydro‐phenanthrene (I). A new asymmetric center at position 2 has been introduced in a fully stereospecific manner by dialkylation with allyl iodide, oxidative degradation of the allylgroups, and lactolization or lactonization of the β‐orientated 2‐acetaldehyde or 2‐acetic acid residue respectively, with the 4β‐hydroxy‐group. Derivatives suitable for the construction of ring D have been obtained by introduction of an acetic acid residue in 1‐position of the tricyclic compounds.