Determination of absolute configuration using circular dichroism: Troger'sbase revisited using vibrational circular dichroism

A new methodology for predicting the Vibrational Circular Dichroism (VCD) s pectra of chiral molecules using Density Functional Theory (DFT) and Gauge- Invariant Atomic Orbitals (GIAOs) permits the direct determination of the a bsolute configuration of organic molecules in solution; application to Trog er's Base leads to the opposite absolute configuration from that deduced fr om electronic CD, confirming the conclusion arrived at from X-ray analysis of a diastereoisomeric salt.