Talk:Diels–Alder reaction/Archive 1

niobium pentachloride
Is niobium pentachloride really the best example of a catalyst? Wouldn't something more common be appropriate?


 * What do you mean with appropriate? niobium pentachloride is just one of many catalysts reported in the literature. So please feel free to add any catalysts you wish to include, when possible with a citation.

V8rik 17:59, 26 January 2006 (UTC)

It's just when I go to do an organic reaction with a Lewis acid, NbCl5 just isn't the first to come to mind; I would have to look up a more common Lewis acid.


 * AlCl3

Electronic stability of s-trans
I removed the sentence The reason for this is that trans conformation allows the electrons from each double bond to very slightly overlap and lower the overall molecular orbital of butadiene. from the section "The diene". The intended topic is probably conjugation, which should be stated if so. But s-cis dienes are also conjugated, so the statement does not support s-trans being prefered. DMacks 03:18, 23 February 2006 (UTC)

ortho, meta, para:
Are these descriptors only used for aromatic systems? But I would not know the right description by myself... Maybe 3,4-disubstituted cyclohexene? The 3,4-disubstituted cyclohexene is favoured over the 3,5-disubstituted cyclohexene...


 * In my experience, one describes the relative positioning of the EWG and EDG substituents relative to each other ("the 1,2-product or 1,4-product is favored, the 1,3-product is not usually formed"). One is concerned with the reaction itself, not the product as a whole. There could be more than one olefin in the product. DMacks 15:15, 8 May 2006 (UTC)

Reverse?
Can this reaction go in the reverse?


 * Ayup...this fact is mentioned in the third sentence of the introductory paragraph. DMacks 01:01, 12 October 2006 (UTC)

Alkynes
In the first sentence it mentions the reaction is between a diene and a alkene. The dienophile can also be a alkyne too, shouldnt this be generalized? —Preceding unsigned comment added by 129.97.58.55 (talk) 21:30, 22 March 2008 (UTC)

Mechanism
I think that mechanism is not valid because is a periciclic reaction. Diels Alder reaction don't have any mechanisn, you can look at every organic books like McMurry or Seyhan — Preceding unsigned comment added by Wololo2 (talk • contribs) 19:35, 20 January 2011 (UTC)

Endo addition rule - product A and product B
I don't think product A is the exo product, since in any product to be a product of this Diels-Alder reaction (and thus, be categorized as either exo or endo), must have the aldehyde group and the methyl group in trans position relatively to each other. Product B is the endo product, but product A is simply epi-B product, not the exo product. —Preceding unsigned comment added by 86.29.37.122 (talk) 19:12, 29 January 2011 (UTC)

The Albrecht Almost Had It [4+2] Cycloaddition
More than twenty years before Diels and Alder (and cited by them), Walther Albrecht studied the double condensation of cyclopentadiene with quinones in the laboratories of Johannes Thiele at Münich. In so doing, he appears to have properly collected and analyzed his data sufficiently to have undermined Thiele’s hoped for double condensation product: the double fulvene. However, the structure was assigned to arise from the 1,4-addition of one Cp to each enone, 2,5-bis-cyclopentadienyl-1,4-cyclohexanedione, rather than the correct D-A product.

Reference: Walther Albrecht, "Addition products of Cyclopentadien and quinones." (translated from the German), Justus Liebigs Annalen der Chemie, 1906, 348, 31-49.

SHOULD THIS BE ADDED TO THE MAIN ARTICLE? AdderUser (talk) 21:54, 16 April 2014 (UTC)

Carey and Sundberg
I highly recommend editors to consider consulting the two books produced by Francis A. Carey and Richard J. Sundberg about Advanced Organic Chemsitry. The two books are split into two parts "Part A: Structure and Mechanisms" and "Part B: Reactions and Synthesis". Zyvov 02:08, 28 October 2016 (UTC)