Determination of absolute configurations and conformations of organic compounds by theoretical calculations of CD spectra

The usefulness and limitations of the CNDO/S method for calculations of rot ational strengths of inherently chiral chromophores are illustrated with ex amples from bridged biphenyls. The more empirical Schellman matrix method i s employed to calculate CD spectra of compounds containing two chirally dis posed chromophores. Analysis of the CD spectra of a compound containing two interacting thioamide groups gives detailed conformational information. An alysis of the CD spectra of two closely analogous 1,2,3,4-tetrahydro-2-aryl -N-formyl-pyridines with spiro structure shows how a small structural chang e can lead to the appearance of a nearly mirror image CD spectrum with reta ined configuration at the spiro atom. (C) 2000 Wiley-Liss, Inc.