Steroids. Part 20. Rearrangements of 5α,6α-epoxy-10β-ethenyl- and 10β-ethenyl-5α-hydroxy-steroids

Abstract

Homoallylic participation is not of major importance in the reactions of 5α,6α-epoxy-10β-ethenyl-steroids with boron trifluoride–ether complex, or in the sulphuric acid-catalysed rearrangement of 10β-ethenyl-5α-hydroxy steroids to the 5β-ethenyl-Δ⁹-compounds. Deuterium substituted in the ethenyl group is not scrambled during the latter rearrangements, and the absence of cationic intermediates other than the C(10) carbocations is indicated.