Reactions of 5-Hydroxy steroids. XIII. The acid-catalysed reactions of Cholestane-4,5-diol 4-acetates and Cholestane-4,5-diol diacetates
ETJ Bathurst, JM Coxon and MP Hartshorn
Australian Journal of Chemistry
27(7) 1505 - 1513
Published: 1974
Abstract
The reaction of 5α-cholestane-4α,5-diol 4-acetate (lb) with sulphuric acid-acetic anhydride-acetic acid occurs almost exclusively by loss of the 6α-proton to give cholest-5-en-4a-yl acetate (3) while dehydration with thionyl chloride-pyridine occurs predominantly (c. 80%) by loss of the 6β-proton. On reaction with D2SO4-DOAc-Ac2O, 5α-cholestane-4β,5-diol 4-acetate (7) undergoes backbone rearrangement to give olefins (9),(10) and (11) without incorporation of deuterium and thus excludes the intermediacy of olefins and cyclopropanes in the rearrangement process. The effect of substituents on these reactions has been rationalized by consideration of the initial conformation of the C5 carbonium ion.https://doi.org/10.1071/CH9741505
© CSIRO 1974