Studies related to the Westphalen rearrangement

The reaction of four 3β-hydroxy-derivatives of Westphalen's diol with lead tetraacetate is described. The major products are the ethers 6β-acetoxy-3β,5-oxaethano-19-nor-5β-cholest-9(10)-ene (11(5]), 6β-acetoxy-9α,10-epoxy-3β,5-oxaethano-19-nor-5β,10α-cholestane, 6β-acetoxy-9β,10-epoxy-3β,5-oxaethano-19-nor-5β, 9β-cholestane and 6β-acetoxy-14-methyl-3β,5-oxa-ethano-18,19-bisnor-5β,8α,9β,10α,14β-cholest-13(17)-ene in which the original 5β-methyl group has been functionalised. Oxidation of (11[5]) with chromic acid gave products of attack at the 9,10-double bond and/or the allylic position 11. The reduction of (11[5)) and subsequent oxidation and boron-trifluoride catalysed cleavage of the tetrahydrofuran ring is described. [Continues.]