Reaction of steroidal alcohols with isobutene. Usefulness of t‐butyl as a hydroxyl‐protecting group in a synthesis of testosterone

Abstract Acid‐catalysed addition of isobutene to steroidal alcohols gives the t‐butyl ethers in high yields. These ethers are acid‐labile, but alkali‐resistant. The t‐butyl group is readily split off with trifluoroacetic acid. The usefulness of the method is demonstrated by a simple synthesis of testosterone benzoate from dehydroepiandrosterone.