a method for the convenient synthesis of the recently isolated allylic gonadal steroids , 3 alpha-hydroxy-4-pregnen-20-one ( 3 alpha-dihydroprogesterone ; 3 alpha-dhp ) and 3 alpha-hydroxy-4-androsten-17-one ( 3 alpha-ha ) , was developed using 4-pregnene-3,20-dione ( progesterone ) and 4-androstene-3,17-dione as substrates and potassium trisiamylborohydride ( ks-selectride ) as reducing agent .
C0012311
dihydroprogesterone
C0033308
progesterone