Three aspects of an absolute configuration on the basis of the stereoisogram approach and revised terminology on related stereochemical concepts

摘要

A tetrahedral skeleton is considered to belong to the RS-stereoisomeric group denoted by T_(d??). By placing proligands on the four positions of the tetrahedral skeleton, the resulting promolecule is considered to belong to a subgroup of T_(d??), where its RS-stereoisomeric properties are illustrated by the corresponding stereoisogram. Three aspects of an absolute configuration, i.e., a chiral aspect, an RS-stereogenic aspect, and a scleral aspect, are formulated on the basis of three attributes of a stereoisogram, i.e., chirality, RS-stereogenicity, and sclerality. The RS-stereodescriptors of the Cahn-Ingold-Prelog (CIP) system are clarified to specify the RS-stereogenic aspect, so that they are assigned to a pair of RS-diastereomers contained in a type-I, type-III, or type-V stereoisogram. To apply the RS-stereodescriptors to the chiral aspect of an absolute configuration, the concept of chirality faithfulness is redefined by proposing odd and even priority permutations.