Rearrangement Of 23-oxospirostanes To The 22-oxo-23-spiroketal Isomers Promoted By Lewis Acids—X-ray Crystal Structure Of (23R,25S)-3β-acetoxy-16β,23:23,26-diepoxy-5β-cholestan-22-one
Michał K. Cyrański, Jadwiga Frelek, Izabella Jastrzębska, Jacek W. Morzycki