Electrocyclic reaction

In organic chemistry, an electrocyclic reaction is a type of pericyclic rearrangement where the net result is one pi bond being converted into one sigma bond or vice versa. These reactions are usually categorized by the following criteria:

• Reactions can be either photochemical or thermal.
• Reactions can be either ring-opening or ring-closing (electrocyclization).
• Depending on the type of reaction (photochemical or thermal) and the number of pi electrons, the reaction can happen through either a conrotatory or disrotatory mechanism.
• The type of rotation determines whether the cis or trans isomer of the product will be formed.