VIBRATIONAL RAMAN OPTICAL-ACTIVITY IN (R)-(-3-METHYLCYCLOHEXANONE - EXPERIMENTAL AND AB-INITIO THEORETICAL-STUDIES AND THE ORIGINS OF THE UNUSUAL COUPLETS())

Vibrational Raman optical activity (ROA) spectra of 3-methylcyclohexan one with excellent signal-to-noise ratio obtained on a new ROA spectro meter and corresponding ab initio theoretical ROA spectra obtained wit h 6-31G and 6-31G basis sets are presented. The experimental ROA spec trum for the (+)-enantiomer compares well with the predicted ROA spect ra for the (R)-configuration of 3-methylcyclohexanone. This allows us to confidently suggest the origins of several bisignate couplets prese nt in the experimental spectrum which had previously attracted much sp eculative discussion.