Intramolecular cation–π interaction in organic synthesis

Controlling molecular conformation is a significantly important issue in a wide variety of organic reactions because the ground state structure is significantly responsible for the transition one. As observed in enzymes and proteins, the cation-pi interaction plays a key role in the formation of the tertiary structure and the biochemical processes. Therefore, the cation-pi interaction would be a promising conformation-controlling tool not only in large molecules, but also in small molecules due to its stronger interaction force. This article describes the utility of the intramolecular cation-pi interaction in various organic syntheses with evidence for the existence of the cation-pi interactions.