Prediction of optical rotation using density functional theory: 6,8-dioxabicyclo[3.2.1]octanes

We report calculations of the optical rotations of six 6,8-dioxabicyclo[3.2 .1]octanes using ab initio density functional theory (DFT). CIAO basis sets are used to ensure origin independence of predicted rotations. Large basis sets including diffuse functions are used to minimize basis set error. The signs of [alpha](D) are correctly predicted. Magnitudes differ from experi ment by 10-20 degrees [dm (g/cc)](-1) on average. Agreement with experiment is improved by inclusion of solvent effects via the Polarized Continuum Mo del (PCM). The results support the conclusion that DFT/GIAO/PCM calculation s of specific rotations can be useful in elucidating the absolute configura tions of chiral molecules. (C) 2000 Elsevier Science Ltd. All rights reserv ed.