ABSOLUTE STEREOCHEMISTRIES AND CONFORMATIONS OF CLERODIN AND CARYOPTIN. WHY CONFLICTING RESULTS IN ABSOLUTE STEREOCHEMISTRY BASED ON CD AND ORD SPECTRA?

Article abstract of DOI:10.1016/S0040-4039(00)94159-5

The reverse of absolute stereochemistries of clerodin and caryoptin means that the correct chirality conflict with the absolute stereochemistries based on Cotton effects.Molecular mechanics and X-ray studies confirmed that the B ring of the 6-keto derivatives retained the boat form as the stable conformer.Furthermore, the steric factors causing the conformational changes were proved by derivation to the strain-free derivatives.The conformation of the B ring in the derivatives changed to the chair form which is confirmed by the X-ray and CD.