Talk:Grignard reaction

Mechanism

All of the mechanism arrows shown for the radical reaction should be single-headed. One of them is mistakenly double. —Preceding unsigned comment added by Ggspring (talk • contribs) 13:57, 1 November 2009 (UTC)

Question

how do you convert acid halide to secondary alcohal by reaction with Grignard reagent??

That can't be done as you describe it. When a Grignard reacts with an acyl halide, a ketone is formed. Usually, a second molecule of the Grignard agent will then react with the carbonyl, giving a tertiary alcohol. If you could prevent this second reaction, you could reduce the ketone to a secondary alcohol, but doing so is hard for acyl halides and the reduction isn't a Grignard reaction. Or you could reduce the acyl halide to an aldehyde and then Grignard rxn would give secondary alcohol, but again, reduction ≠ Grignard. DMacks 05:55, 8 March 2006 (UTC)

Clean up

In think that in the hast to do the clean up that the article has been harmed by the removal of details of reactions with non-carbon electrophiles such as SnCl4. These are as much a part of Grignard chemistry as the reaction of the 'organic' carbon based electrophiles.Cadmium

So I did. Oops. I'll try to get to putting those back in either tonight or tomorrow. However, if you want to do it, go right ahead. ~K 15:42, 31 July 2006 (UTC)

You might also want to add NaBF4 + 4 RMgX to form Na BR4, this this the basics of how to make BPh4 anions.Cadmium

You beat me to it and did a much better job than I had planned. Thanky. ~K 17:23, 5 August 2006 (UTC)

Ye both did a bad job. —Preceding unsigned comment added by 89.100.95.81 (talk) 19:27, 9 April 2011 (UTC)

Chemical drawing needed

What exactly is missing? --Rifleman 82 00:18, 13 September 2007 (UTC)

File:OrganoelementGrignard.png is a red link, I don't know if someone had intended to upload something but forgot, or what. shoy 19:51, 13 September 2007 (UTC)

Fixed. It should be Image:Organoelementgrignard.png. --Itub (talk) 08:27, 7 August 2008 (UTC)

Couplingis severly wrong

nonylmagnesium bromide reacts with an aryl chloride to a nonyl benzoic acid This is not whats in the mentioned literature whic is the production of carboxylic acids by the reaction of Grignard reaction with carbondioxide.--Stone (talk) 10:21, 8 February 2008 (UTC)

doi:10.1016/S0022-328X(96)06794-0 might be a better ref.--Stone (talk) 10:25, 8 February 2008 (UTC)

Further more the reaction itself is not a very good example because the Grignard would normaly go for the ester group and not for the bromine. JACS 1948 This has to be pointed out! --Stone (talk) 10:31, 8 February 2008 (UTC)

An extra reaction

Might want to include the reaction with a di ester (e.g. (EtO)₂ C=O) Its an interesting reaction, and has applications in dye manufacture for making crystal violet 129.67.121.34 (talk) 13:46, 17 February 2008 (UTC) Will

References

Reference

Hello,

I am researching the Grignard reaction and am trying to chase up the references, particually the reviews. However i am unsure of what "Comp. Org. Syn." is, i assume organic synthesis but do not know what comp. is. Can anyone help? Thanks86.16.112.9 (talk) 20:15, 28 October 2008 (UTC)

Deletion or Re-write

"Grignard reagents react with electrophilic chemical compounds. Such reactions are not ionic; the Grignard reagent exists as an organometallic cluster (in ether)."

This is very poorly written and ill-placed. The information in these two sentences should be one sentence and none of that needs to even be in the article. —Preceding unsigned comment added by 137.155.208.30 (talk) 15:52, 5 December 2008 (UTC)

Nature of the Mg-X bond

Forgive my ignorance, but is the Mg-X bond (X=halogen) covalent or ionic? (I presume that the R-Mg bond is covalent, right?) Thanks, --Jorge Stolfi (talk) 18:45, 16 November 2009 (UTC)

I'm no expert in the structure of Grignard reagents, but I suspect that the answer is "yes". ;-) There's probably a mix of ionic and covalent character, and how it looks will depend on the solvent and other conditions. That said, I'm now looking at Greenwood & Earnshaw's Chemistry of the Elements and it has a nice diagram showing the messy situation: a number of equilibria including dimerization, association, dissociation, ionization, and disproportionation. Since one of these reactions is the dissociation of the halide ion, I think one could say that the Mg-X bond is ionic. PS: it would be nice to add such a figure to the article. ;-) --Itub (talk) 20:39, 16 November 2009 (UTC)

the Mg-X bond is not important here the important. the important thing with this reaction is you form a delta- carbon that can react with delta+ carbons like all the carbonyl groups and it derivatives. there exist an other reactive similar and produced the same way that are the lithiens that react in tha same way but don't form Li-X bond. —Preceding unsigned comment added by Gavyns (talk • contribs) 12:15, 17 October 2010 (UTC)

reaction with grignard

I just wanted to point out the the reaction of Grignard on a nitrile from a imine and often forms a ketone after hydrolysis. it's just that under certain circumstance of stabilization with double bonds or benzen rings it can stay as a imine.

Ok Mistura20 (talk) 01:48, 12 October 2022 (UTC)

Grignard Reagent Mechanism

I have heard from two professors and a textbook that the exact mechanism for the formation of a Grignard reagent is still unknown. I found a few sources that confirm this, so I edited the reagent section and cited a source. saumaun (talk) 17:10, 23 September 2011 (UTC)

Reactions with other electrophiles

I am not quite sure how the reaction on RMgX with R'-CN (nitrile) produces a ketone as a product. It does not seem obvious where the Oxygen for the Carbonyl would come from. If this is a multistep reaction, then the second reagent system should be listed as well. — Preceding unsigned comment added by Am0210 (talk • contribs) 00:37, 19 February 2014 (UTC)

Chemists often fail to mention hydrolysis, but I mention this aspect to address the issue you raised. --Smokefoot (talk) 01:46, 19 February 2014 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Grignard reaction/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

A well written and informative piece. It provides helpful background information and practical tips. However, I think some safety information would strengthen it.

Last edited at 15:55, 24 January 2008 (UTC). Substituted at 16:46, 29 April 2016 (UTC)

Split the article?

The article could be split into Grignard reaction (RMgX + organic carbonyls) and Grignard reagent.

Arguments for a split:

• These topics are distinct
• make the articles more manageable sizes
• the Grignard reaction is far less important (IMHO) than the making and use of RMgX

Arguments against a split:

• most/many chemists think that the Grignard reaction is the making of the reagent

--Smokefoot (talk) 18:16, 19 February 2017 (UTC)

Split proposal

I tried this before (see above), but no one seemed to care. I would make the split this weekend by cut and pasting content from the present article into the current redirect page Grignard reagent. Then I would do the dirty work of addressing all the links. Suggestions welcome.--Smokefoot (talk) 02:34, 7 March 2019 (UTC)

Support. Organic chemist, here, I agree with a split. Organotin chemistry is a separate page from the Stille reaction and Ylide is a separate page from the Wittig reaction. So there is definitely precedent for this, particularly to allow for discussion of more than one application of the reagent. Regarding the earlier "argument against" you mentioned, any chemist who calls the synthesis of a Grignard reagent a "Grignard reaction" is objectively wrong and I don't think that incorrect idea should hold any weight. 155.33.134.45 (talk) 21:53, 7 March 2019 (UTC)

Grignard reaction = RMgX + ketone/aldehyde

March: "The addition of Grignard reagents to aldehydes and ketones is known as the Grignard reaction". Grignard reagents do lots of reactions, a subset being the Grignard reaction. --Smokefoot (talk) 19:53, 21 April 2023 (UTC)

Sorry about that. I've seen conflicting sources on the definition. For example https://www.ebi.ac.uk/ols/ontologies/rxno/terms?iri=http%3A%2F%2Fpurl.obolibrary.org%2Fobo%2FRXNO_0000014 and also within the sources of the german Wikipedia page for it? LoomCreek (talk) 21:07, 21 April 2023 (UTC)

If you help clarify this I would very much appreciate it. LoomCreek (talk) 21:10, 21 April 2023 (UTC)

Thanks for opening the discussion. Here are various comments on the situation.

• Many professional chemists, me included for most of my career, thought that RMgX + anything = Grignard reaction, so the confusion is understandable. The German article continues this traditional mistake. I just left a note there, and we can watch what they say.
• Jerry March's book (now in its 6th edition) is widely considered authoritative. You can ask other editors. That book is very clear on the limited scope of the Grignard reaction :"The addition of Grignard reagents to aldehydes and ketones is known as the Grignard reaction".
• The IUPAC Goldbook does not address the topic.
• Of course, I could be wrong.--Smokefoot (talk) 21:43, 21 April 2023 (UTC)

  Ah okay thank you so much for the feedback. Ill hold to your opinion unless some other evidence comes to light. I see that the German Wikipedia page actually cites an old (what seems to be primary?) source from 1900 on the online French archives Gallica. Which I actually have a little bit of experience using with from editing a completely unrelated article a while back. Id likely have to use image translate as they're not always transcribed, so any results I find could be suspect.) So, we would want to confirm with someone relatively fluent in French. LoomCreek (talk) 08:52, 23 April 2023 (UTC)

  I was too curious and I read it. It was the original investigation by Victor Grignard published in January 1900. It does seem to focus on secondary and tertiary alcohols being formed. I'd read it yourself if you'd like to check. (Although it does mention benzyl bromide, not as a reactant though as far as a can tell but as a rudimentary Grignard reagent, that Grignard notes is worse then MgBr.)

  As a note It's possible the definition in German developed differently and is slightly broader.

  https://gallica.bnf.fr/ark:/12148/bpt6k3086n/f1323.item.langDE (Full Section is Pg 1322-1324) LoomCreek (talk) 09:30, 23 April 2023 (UTC)

Yes, March's definition is about making such alcohols from RCHO and R2CO. The German Wiki is less as active than .en Wiki. There has been no response to my note there. The exact definition of "Grignard reaction" is a picky point, less important than an understanding of the underlying chemistry. Nothing to get hung about.--Smokefoot (talk) 12:57, 23 April 2023 (UTC)

@Smokefoot Yeah, it was just a curiosity. I appreciate the heads up. LoomCreek (talk) 19:41, 23 April 2023 (UTC)

As an update there does seem to be an extended definition for Grignard reactions according to the royal chemistry society. https://www.rsc.org/Merck-Index/reaction/r177/

I still think there should be two separate pages by the way, Grignard reagents deserve its own page regardless.

But there is a broader definition that might make explanations of the mechanics more accessible. Just as long as we clarify a distinction between the classical definition and modern one.

I might also make new graphics, but instead the current division that's split between carbonyls and Heteroatom electrophiles. Instead it would be one based on which create secondary and tertiary alcohols (through addition to the carbonyl), and which create other products (for example the 1,4 addition to 3-Penten-2-one). While keeping the current graphics as is on Grignard reagent.

I'm just going to be uploading new ones and using them on this page. Because I think it could be really useful to make how this mechanism interacts under different conditions clearer. LoomCreek (talk) 01:14, 24 April 2023 (UTC)

Wiki Education assignment: CHEM 300

This article was the subject of a Wiki Education Foundation-supported course assignment, between 6 September 2023 and 7 December 2023. Further details are available on the course page. Student editor(s): Ccustodi, Toady03 (article contribs). Peer reviewers: Dorsanil, 1597 CE, Moya.priroda, Berkeker.22, Cmsgarbi.

— Assignment last updated by CHEM 300 UBC CJA (talk) 18:01, 8 November 2023 (UTC)