## Wikipedia - Elektrosyklinen reaktio (fi) Wikipedia - Reazione elettrociclica (it) electrocyclic reaction

Also contains definitions of: conrotatory, disrotatory
https://doi.org/10.1351/goldbook.E01948
A @[email protected] that involves the formation of a σ-bond between the termini of a fully @[email protected] linear π-electron system (or a linear fragment of a π-electron system) and a decrease by one in the number of π-bonds, or the reverse of that process. For example:
E01948-1.png
The stereochemistry of such a process is termed 'conrotatory' or @[email protected] if the substituents at the interacting termini of the conjugated system both rotate in the same sense, e.g.
E01948-2.png
or 'disrotatory' (or @[email protected]) if one terminus rotates in a clockwise and the other in a counter-clockwise sense, e.g.
E01948-3.png