Absolute Configuration and Conformational Analysis of Chiral Compounds via Experimental and Theoretical Prediction of Chiroptical Properties: ORD, ECD, and VCD

Methodology, scope, and advantages of electronic circular dichroism (ECD), vibrational circular dichroism (VCD), and optical rotatory dispersion (ORD) are presented in a tutorial way to help in choosing a suitable combination of spectroscopic tools when facing a quest for structural elucidation for small-medium organic chiral molecules. This chapter does not pretend to be a review but rather focuses on recent work particularly chosen as case examples. The rotation of the plane polarization of a linearly polarized light (LPL) is known since two centuries. This response, referred as optical rotation, was found first in quartz and then in solutions of chiral organic molecules. Soon, optical rotation and ORD, that is, the optical rotation at different wavelengths, were used to distinguish and determine the absolute configuration (AC). More recently, ECD and VCD chiroptical spectroscopies became more versatile for the characterization of chiral compounds.