The santonins. Qantitative conformational analysis
White DNJ., Sim GA.
Empirical valence force-field calculations have been used to investigate the conformations and relative strain energies of α-santonin, β-santonin, and their C(6) epimers. The cis-fused γ-lactone ring is energetically preferred over the trans and the nearly eclipsed C(13)-C(11)-C(12) = 0 torsion angle plays a key role in stabilising the isomers with a pseudo-equatorial Me group at C(11). © 1973.