Talk:Diels–Alder reaction

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Predicting sterochemistry

It is not true for the endo transition state that the substituents on dienophile and 1,4-substituents on diene will always point towards the same side of the newly formed ring...In the picture below, it just happens that the endo transition state will yield substituents on same side of the ring.

can be very unclear to someone who does not realize that Cp is one of the few, if not only dienes with bulky substituents naturally in the inner position. I favor stating the rules which say

"out-endo-cis" (corollary "out-exo-trans")

"in-exo-cis"

where "out" or "in" refer to the position of a diene substituent, "endo" or "exo" refer to the orientation of the dienophile substituent, and "cis" or "trans" refer to the stereochemistry of the two substituents in question.

Thoughts?

Image problems: epimerization

The figure titled "Epimerization in DA reaction" could do with some alterations. Firstly structure B loses a methylgroup. Secondly for an easier to understand diagram i believe the hydrogen's on stereocenters should be included in the twistchair conformations — Preceding unsigned comment added by 124.168.1.29 (talk) 05:56, 20 February 2013‎ (UTC)[reply]

Why is the Named Dienes diagram so huge?

That can't be right. How do we get it to be a normal size? 128.101.184.163 (talk) 15:24, 16 May 2014 (UTC)[reply]

Thanks for letting us know! I fixed it. DMacks (talk) 15:29, 16 May 2014 (UTC)[reply]

I tried to manipulate it, but gave up and just replaced it with a thumb. Maybe someone else can help? @DMacks:--Smokefoot (talk) 15:02, 23 September 2022 (UTC)[reply]

Undue emphasis on total synthesis

The section on uses seems to be highly focused on listing US-all stars who use this reaction that was discovered before almost all of them were born. The section is an excellent overview or perspective on selected applications of D-A reaction in total synthesis. But..., we probably want readers to learn about where the reaction is used in the real world vs its applications to total syntheses, few of which are practiced. One idea would be to create a separate article or section on historical development of D-A reaction. That is what I did today. But other editors might have better ideas.--Smokefoot (talk) 18:17, 27 December 2017 (UTC)[reply]

Also many reaction schemes show much more than the D-A reaction. So I cropped one to remove the tangential info. If and when I become more skilled with cropping, I may do others. --Smokefoot (talk) 14:58, 23 September 2022 (UTC)[reply]

Perhaps this review could provide some better examples doi:10.1002/anie.201201636 e.g. Buprenorphine. There's likely some simple industrial process which escape academic interest but which operate at significant quantities, 4-vinylcyclohexene might qualify. Captan and Captafol look likely to involve DA chemistry --Project Osprey (talk) 22:52, 24 September 2022 (UTC)[reply]

Industrial uses of D–A? PMID:23447554 is a 2013 review, and Derek Lowe has an article[1]. DMacks (talk) 03:26, 25 September 2022 (UTC)[reply]

Lewis acid catalysis

I read the first reference and I think this could use further elucidation. ″It is found that Lewis acids accelerate the Diels–Alder reaction by reducing the destabilizing steric Pauli repulsion between the interacting diene and dienophile and not by lowering the energy of the dienophile's LUMO...″ I feel as though I have a reasonable grasp of chemical principles, but I don't know what this means.

Further, the authors argue the Lewis acid coordinated with the dienophile. Intuitively, I am thinking it will pull electrons toward the Lewis acid and away from the dienophile. Logically, an electron rich diene reacts at a higher rate. Is my thinking wrong or are the authors reporting the calculations for the HOMO and LUMO energies do not match the actual reaction rates? Petedskier (talk) 20:51, 26 December 2024 (UTC)PW[reply]