Circular dichroism spectra and molecular geometry of six-membered ring anhydrides and imides

Abstract

Several six-membered ring anhydrides and imides of known absolute configuration have been synthesized and their c.d. spectra measured. It has been established that the shape of the c.d. curves of anhydrides is generally similar to those of the corresponding imides. The Cotton effect sign of relatively rigid bicyclic compounds is correctly predicted by the octant rule. The c.d. spectra of substituted glutaric anhydrides and imides are discussed in terms of the conformational equilibria between half-boat and twist-boat conformers. The geometries and relative energies of these forms have been calculated by the molecular mechanics method.