Topologically activated sites in benzenoid hydrocarbons, Polyacenes and benzo-annelated polyacenes

摘要

If the interruption of conjugation at a pair of carbon atoms of a benzenoid hydrocarbon, in the para position to each other, increases the Kekule structure count, then these sites are said to be topologically activated. Oxidation, Diels-Alder addition, etc. usually occur at topologically activated sites. The rules determining the existence and location of topologically activated sites in polyacenes and benzo-annelated polyacenes are established.