Collect. Czech. Chem. Commun. 1989, 54, 413-429

Acid-catalyzed rearrangements of an A(1)-nor-triterpenoid 2α,3α-epoxide

Jiří Klinota, Jiří Liškaa, Alena Forgáčováa, Miloš Buděšínskýb, Jiří Protivaa, Stanislav Hilgarda and Alois Vystrčila

a Department of Organic Chemistry, Charles University, 128 40 Prague 2
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


Reactions of 2α,3α-epoxide X, derived from 19β,28-epoxy-A(1)-nor-18α-oleanane, with acids proceed with migration of the 10β-methyl group into the position 2β, giving rise to unsaturated alcohols XII and XIV and diene IX. Reaction with boron trifluoride etherate afforded ketone XI in addition to XII and XIV. Olefin VIII rearranged in acidic medium to give olefins XXVI and XXVII. The rearranged products were converted into other derivatives and their structure was established by 1H and 13C NMR, IR, UV and mass spectra.