VIBRATIONAL CIRCULAR-DICHROISM SPECTROSCOPY OF CHIRAL PHEROMONES - FRONTALIN (1,5-DIMETHYL-6,8-DIOXABICYCLO[3.2.1]OCTANE)

Ab initio density functional theory (DFT) is used to predict the vibra tional absorption and circular dichroism spectra of the insect pheromo ne 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane: frontalin. Excellent ag reement with experimental spectra is obtained for the structure in whi ch the six-membered ring is in a chair conformation and the seven-memb ered ring is in a boat conformation. Vibrational circular dichroism (V CD) intensities, predicted on the basis of the previously determined a bsolute configuration, are in excellent agreement with experiment. We conclude that VCD spectroscopy, in combination with ab initio DFT, is now an efficient tool for determining the absolute configuration and/o r conformation of chiral organic molecules, including pheromones. (C) 1998 Elsevier Science Ltd. All rights reserved.