Thermodynamically controlled enol acetylation of 17β-acetoxy-2α-phenylandrosta-4, 9 (11)- dien-3-one (3) affords a mixture of 2α-phenylandrosta-3, 5, 9 (11)-triene-3, 17β-diol diacetate (4) and 2-phenylandrosta-2, 4, 9 (11)-triene-3, 17β-diol diacetate (5) in the ratio