South African Croton gratissimus Burch. var. gratissimus (Euphorbiaceae), Russian Pinus pumila (Pall.) Regel (Pinaceae) and
Madagascan Tachiadenus longiflorus Griseb. (Gentianaceae) gave unusual natural products, gratissimol (1),  pumilol (2) and
langaside (3) respectively whose skeleta have not been reported previously. The absolute configurations of 1, 2 and 3 were
determined by comparing their theoretically calculated and experimental ECD curves. Conformational searches were done on
possible isomers that were consistent to correlations in their NOESY spectra using MMFF basis set built into Spartan08
software and conformers which were under 2 kcal/mol subjected to TDDFT calculations using a B3LYP method at 6-31G (d, f)
level built into Gaussian09 software. The resulting ECD curves of the selected conformers were Boltzmann weighted and
compared to the experimental ECD curves for 1, 2 and 3.