Reaction Center and Environment:

  1. Reacting center (in red) includes atoms and bonds which are directly involved in the reaction. They include:
    • bonds which change order (or orientation) during the reaction,
    • atoms connected to these bonds, and
    • atoms whose properties change (include charge, stereo).

  2. One atom shell out from the reacting center (in blue) includes any atoms one away from the reacting atoms, and the bonds connecting them to the reacting center.

  3. The extended environment (green) includes additional conjugation connected to any of the atoms or bonds already included.

    NOTE: This definition of a generic reaction is subject to arguement. For example, the carboxylate methoxy-group is not included. One can envision a heirarchy of levels of generality of reaction types.