Synthesis of 5alpha-pregna-1,20-dien-3-one.

5ALPHA-Pregna-1,20-dien-3-one has been synthesized from 3beta-hydroxy-5alpha-pregnan-20-one by reaction of the tosylhydrazone with butyllithium to introduce the vinyl moiety. Oxidation of the alcohol and treatment of the anion of the resulting ketone with benzeneselenenyl chloride gave the 2-phenylseleno derivative. This afforded the conjugated enone on oxidative elimination.