The determination of absolute configuration of bioactive compounds continues to be one of the most challenging problems in the organic and pharmacological chemistry.This is attributable the fact that the enantiomers of a particular bio-active compound may demonstrate differences of up to several orders of magnitude in their pharmaceutical effects and potency at the same receptor.They may also exhibit a significantly different ADME profiles.The fact that one of the enantiomers is more active than its counterpart,which may even be toxic,necessitates the need to use the enantiomerically pure products to avoid possible adverse effects.Thus,an access to the practical methods allowing for the unequivocal and reliable determination of the absolute stereochemistry of such bioactive compounds is vital for further enhancement of their bioactivity by the rational synthetic modifications.In this context,the chiroptical methods and the circular dichroism (CD) spectroscopy specifically,appear to be sensitive,fast,and convenient methods for the stereochemical assignment provided that the compounds studied are non-racemic.