Figure 1.

Calculating DAS (A) Scores reflect opposing enantiomorphs based on cross-product direction and geometric center. Enantiomers [(2R,3R)-2-(chloromethyl)-3-propyloxirane and (2S,3S)-2-(chloromethyl)-3-propyloxirane] with two stereocenters are shown. (B) Two triangles are visualized in both enantiomers. These triangles encompass the same triplets of atoms between the two molecules. Four tetramers formed by the atom triplets and molecular center are visualized. i, j, k, and i', j', k' reflect the order of these atoms in either molecule. Importance of atom ordering is shown based on the direction of cross product (red arrow) and location of molecular center (black circle). (C) Volume and score calculations for the four tetrahedrons across both enantiomers are shown. Note the opposite signs and scores between the two enantiomers’ tetrahedrons.