The lithium-ammonia overreduction of ll-oxo-5α,14β-cholest-8-en-3β-ol (1) was shown to give equal amounts of 5α,8α,9a, 14β-cholestane-3β,llβ-diol (2) and 5α,8β,9α,14β-cholestane-3β,lla-diol (3) by conversion of the diols to hydrocarbons of known stereochemistry. In contrast to 14α- and 14β-steroidal 11-ketosapogenins (which are stable to base), the 5α,8α,9α, 14β-11-ones in the present study provided through base equilibration a route to the unknown 8α,9β,14β stereochemistry. The CD spectra of the ll-keto-5α, 8α,9α,14β-, and -5α,8β, 39α, 14β-, and -50, 8α,9β,14β-steroids provide evidence for nonchair conformations in rings B and/or C of the steroid skeleton.
All Science Journal Classification (ASJC) codes
- Organic Chemistry