Are There Only Fold Catastrophes in the Diels–Alder Reaction Between Ethylene and 1,3–Butadiene?

27 January 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


This work revisits the topological characterization of the Diels–Alder reaction between 1,3–butadiene and ethylene. In contrast to the currently accepted rationalization, we here provide strong evidence in support of a representation in terms of seven structural stability domains separated by a sequence of 10 elementary catastrophes, but all only of the fold type, i.e., C4H6 + C2H4 : 1–7– [FF]F[FF][FF][FF]F–0 : C6H10. Such an unexpected finding provides fundamental new insights opening simplifying perspectives concerning the rationalization of the CC bond formation in pericyclic reactions in terms of the simplest Thom’s elementary catastrophe, namely the one–(state) variable, one–(control) parameter function.


Diels-Alder reaction
electron localization function ELF
bonding evolution theory (BET)
Catastrophe theory
fold catastrophe model
cusp catastrophe model


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.