text: Using correlation diagrams one can derive selection rules for the following generalized classes of pericyclic reactions.  Each of these particular classes is further generalized in the generalized Woodward–Hoffmann rules.  The more inclusive bond topology descriptors antarafacial and suprafacial subsume the terms conrotatory and disrotatory, respectively.  Antarafacial refers to bond making or breaking through the opposite face of a π system, p orbital, or σ bond, while suprafacial refers to the process occurring through the same face.  A suprafacial transformation at a chiral center preserves stereochemistry, whereas an antarafacial transformation reverses stereochemistry.