Enantiomeric and Diastereomeric Relationships of Ethylene Derivatives. Restructuring Stereochemistry by a Group-Theoretical and Combinatorial Approach

Abstract

To restructure stereochemistry into a systematic format, enantiomeric and diastereomeric relationships have been investigated by using ethylene derivatives as examples in the light of a new group-theoretical and combinatorial approach. On one hand, enantiomeric relationship for ethylene derivatives has been characterized by means of a point group of order 8 (D 2h ), where chirality fittingness based on the sphericity concept has been applied to the enumeration of stereoisomers. On the other hand, diastereomeric relationship for ethylene derivatives has been examined by a permutation group of order 8 (S 9 [4]), which is a subgroup of the symmetric group of order 4 (S [4]) and isomorphic to a point group D 2d . The subgroups of S 9 [4] have been classified into stereogenic and astereogenic ones. A stereogenic subgroup corresponds to a pair of diastereomers, while an astereogenic subgroup is assigned to a self-diastereomer. The relationship between diastereomers and constitutional isomers have been also discussed.