Talk:Alkyne zipper reaction

Wiki Education Foundation-supported course assignment

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Mdbreshears. Peer reviewers: Mlasky8.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 13:52, 16 January 2022 (UTC)

Mechanism

Hi! I am new to editing Wikipedia so apologies if I am not using the Talk page correctly. I added a mechanism section to this page with figures describing the arrow-pushing mechanism. I mainly used two sources: the original 1997 JACS paper and a secondary source (SynArchive.com). Let me know if there are changes I should make. Thanks! :) — Preceding unsigned comment added by Mdbreshears (talk • contribs) 03:43, 20 December 2017 (UTC)

Hi Mdbreshears, thanks for adding a mechanism, and you are using the talk page correctly, just with a couple of tweaks:

1. It is usual to add to a talk page by clicking "new section" at the top and adding a heading, rather than just editing the page itself. If you do just edit the page, add a heading to start a new discussion, as I have with == Mechanism ==
2. Sign your comments with ~~~~ which will add a signature to the end of your post (as Signbot has done to your post, above).

Regarding the addition itself, it is certainly welcome and a mechanism was needed, but I would suggest that some of the language that you have used is a little informal for encyclopaedic writing – hydrides "plucking" a proton and electrons being kicked, etc. Taking your first paragraph as an example (without refs): The alkyne zipper reaction requires a strong base to proceed. Potassium hydride, a volatile strong base, can be used to initiate the reaction. First, the hydride plucks a proton off of one of the amine groups of the 3-aminopropylamine. The electrons from the hydrogen-nitrogen bond kick onto the nitrogen atom. This is favorable because the nitrogen atom is electronegative and can hold the resulting negative charge. Hydrogen gas (H₂) bubbles off, driving the reaction forward. The positively charged potassium ion stabilizes the resulting negatively charged 3-aminopropylamine.

Here is a redraft:

The alkyne zipper reaction is catalysed by the 3-aminopropylamide anion, which is generated in situ by the deprotonation of 3-aminopropylamine by potassium hydride, a superbase. This initiation step is driven to completion by the formation and subsequent loss of hydrogen gas as it bubbles from the solution. Alternatives to potassium hydride have been sought as it is expensive and hazardous, being both pyrophoric and extremely sensitive to water. The active catalytic species is similarly sensitive and highly reactive – it is a sufficiently powerful Brønsted–Lowry base to generate carbanions from hydrocarbon species. It is stabilised by its negative charge being borne by a highly electronegative nitrogen atom, by the presence of a potassium counterion for charge balance, and by the careful exclusion of air and moisture using Schlenk techniques. 3-Aminopropylamine is used as the solvent as well as a reagent, thereby avoiding the potential for side reactions that would consume with the catalyst.

What do you think? EdChem (talk) 09:36, 20 December 2017 (UTC)

Sorry EdChem: I made some of the modifications you suggested. For the student - this reaction involves a potassium amide. These are probably not salts with separated anions. Also please do not include any words in your artwork.--Smokefoot (talk) 14:33, 20 December 2017 (UTC)

Why "Sorry", Smokefoot? I'm sure we'd largely agree on unencyclopaedic tone in the additions that needed addressing, and anyone can make changes. The student can engage in a discussion if s/he ever returns, which might also benefit the instructor, though we both know that these class activities can be problematic. At least the intent was to add something that is clearly relevant to the article and which was an omission. EdChem (talk) 11:02, 21 December 2017 (UTC)

After I edited, I realized that you were engaging the student and my changes might be interfering, but it appears that the student is not very interactive. Not very good content by this student, not that I was much better at that stage. Cheers,--Smokefoot (talk) 16:09, 21 December 2017 (UTC)

The academic side of me says I would hope for better writing from a third year university student in organic chemistry, at least in Australia (3 year pass degrees and all that), but the Wikipedian was glad to see a mechanism being added - an appropriate addition, and a suitably focused task for a student edit. That's much better than much of the student work where the underlying topic is a duplication of an existing topic or is fundamentally unencyclopaedic (synthesis, for example). The language in this additions is a problem and a book reference to support the papers would be appropriate, but I was thinking this was at least a basis for a discussion with the student and / or the instructor. Have you noticed the proposed additions to the organometallic chemistry article from this same class? You commented on the proposals but the sandbox is less than encouraging, IMO – "[p]erhaps among the most infamous examples of organometallic catalysis is the Suzuki-Miyaura coupling reaction" caught my eye as something I wouldn't leave unchanged! There is also an addition to the oseltamivir total synthesis article, which again is a suitable topic for addition to the article and an area where the article had a gap. So, there are variable additions from this class.

Smokefoot, you are correct that I was trying to open a dialogue with the student, though I would have made changes in a couple of days if no response came (as would not be surprising) – so, yes, your edit could have been an interference (in theory), but the students / instructor also need to understand that once a change is in article space, "anyone can edit" means anyone can edit. The instructor is Mclaughl, who might like to join this discussion and so be better able to advise / support future projects. EdChem (talk) 00:29, 22 December 2017 (UTC)

EdChem & Smokefoot, thank you for your edits and discussion. I appreciate the input and advice. I have removed the text from my artwork and have reintegrated it into the article. I believe the visualization of the molecules is helpful. Smokefoot, your assertion that the ions probably do not exist in solution is not necessarily true. It would depend on the solvent in question. And therefore, I believe that portraying the molecules in ion form helps users understand the stabilizing effects of using potassium hydride to catalyze the reaction and form the amide anion.

Also, to be clear, I fully understand that anyone can edit a Wikipedia article. In fact, that is what I appreciate about Wikipedia. So again, thank you for your contributions. Mdbreshears (talk) 21:33, 22 December 2017 (UTC)