Synthesis of 2′,2′-difluoro-6,7-dihydro-16-methylenecyclopropa[6,7]progesterone analogues

17α-Acetoxy-2′,2′,6β-trifluoro-6β,7β-dihydro-16-methylenecyclopropa[6,7]progesterone (9) and its Δ1-analogue (10) have been synthesised by a ten-step reaction sequence from 3-hydroxy-16-methylpregna-5,16-dien-20-one (1).