Published
Author Henry Rzepa
A dichotomy is a division into two mutually exclusive, opposed, or contradictory groups. Consider the reaction below*.* The bicyclic pentadiene on the left could in principle open on heating to give the monocyclic [12]-annulene (blue or red) via what is called an electrocyclic reaction as either a six (red) or eight (blue) electron process. These two possibilities represent our dichotomy;