Collect. Czech. Chem. Commun. 1981, 46, 941-946

Unusual cyclization in the 11-hydroxy-1βH,5βH,6βH,7αH-guaian-6,12-olide series

Zdeněk Samek, Tomáš Vaněk and Miroslav Holub

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


Derivatives of the keto triester II, particularly the ether VI, were investigated by 1H-NMR and CD spectroscopy. Formation of the ether VI and comparison of its parameters with those of other described compounds prove that the originally suggested steric structure of acetylisomontanolide (VII) is correct.