A general method to predict optical rotations of chiral molecules from their structures

The relationship of the chiroptical response of a molecule to its absolution configuration does not exist now. In this letter, I intend to report a general rule with exceptions to predict the sign of optical rotation of chiral molecules with a RCHXY structure from their absolute configurations using the Hammett constant, sigma(p), which is based on the electron withdrawing/donating power of functional groups. In this rule, a priority list of functional groups based on the electron withdrawing powers of the groups are used. When the lowest priority group is in the back of the molecule, a clockwise arrangement of the other three priorities from the most electron withdrawing to the least withdrawing (1-2-3) is predicted to be dextrorotatory, the counterclockwise arrangement is predicted to be levorotatory.

Automated summary

In this letter, a general rule is proposed to predict the sign of optical rotation of chiral molecules with a RCHXY structure from their absolute configurations using the Hammett constant, sigma(p), based on the electron withdrawing/donating power of functional groups. The rule uses a priority list of functional groups based on their electron withdrawing powers, where a clockwise arrangement of the other three priorities from the most electron withdrawing to the least withdrawing (1-2-3) predicts dextrorotation, and a counterclockwise arrangement predicts levorotation.