88. “Acid-Catalysed Backbone Rearrangement of cholesta-6,8(14)-dienes”
    Liu, R.-M.; Chillier, X. F. D.; Kamalaprija, P.; Burger, U.; Gülaçar, F. O.
    Helv. Chim. Acta 1996, 79, 989-998.

Rearrangement of 5α- and 5β-cholesta-6,8(14)-dienes (13a and 13b, resp.) in the presence of anhydrous toluene-4-sulfonic acid in acetic acid leads to 5α- and 5β-12(13 14)-abeo-cholesta-8,13(17)-dienes (15a and 15b, resp.) via 5α- and 5β-cholesta-8,14-dienes (14a and14b, resp.), respectively. Epimerization at C(20) of the spirosteradienes 15a and 15b occurs with increasing reaction time. Molecular-mechanics calculation of the relative stabilities of these compounds and of congeners thereof is in agreement with the observed reaction pathway.

DOI : 10.1002/hlca.19960790407 

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