Abstract A six step transformation of prednisolone to 17α, 21-dihydroxy-9β, 11β-epoxy-16α- amethylpregna-1, 4-diene-3, 20-dione 21-acetate has been achieved in 13% unoptimised yield. Novel conditions for effecting a Mattox rearrangement and double dehydration of prednisolone were identified. Enhanced knowledge on the oxidation of silyl Δ 19, 20-enol ethers and structural factors that impact the success of the oxidation are also presented.
