Molecular optical rotations and structures

Optical rotations of nine different conformers of chiral enflurane [(H)(F)(Cl)C(CF2OCF2H)] have been calculated ab initio. The population weighted net specific rotation for the (R)-configuration is -1.3 at the 6-31G* level and -1.7 at the DZP level, which is close to the experimental value. As the ab initio predicted optical rotations in the majority of the molecules studied to date are found to compare favorably with the experimental values, it appears that optical rotations provide a convenient alternative approach to determine the absolute configuration and predominant conformations of chiral molecules. (C) 1997 Elsevier Science Ltd.