Talk:Sonogashira coupling

Exposed to air
Where is the exidence that the reactants can be exposed to oxigen? I will have to remove the statement if it is not substantiated. My limited work in this field has shown air is a problem. Hobo 07:18, 28 October 2006 (UTC)
 * I'm guessing they're referring to some of the air-stable Buchwald type catalysts such as found at Org. Lett. 2003, 5, 2413, or Angew. Chem. Int. Ed. Eng. 2002, 41, 3668. I don't have a ref for one of these being used in a Sonogashira, but it is plausible.  Perhaps look at Stephen Buchwald's recent publications and see if he's published on this topic recently - and could you perhaps add the reference here?  I've never run one of these, myself. Thanks, Walkerma 18:15, 28 October 2006 (UTC)


 * Solvents do not generally need to be degassed to perform this reaction, suggesting that air stability is not a major issue, although they are performed under an inert (argon/nitrogen) atmosphere.129.67.38.53 (talk) 20:09, 24 June 2008 (UTC)

Deprotonation of Alkynes:
Citing: "The employed amines such as diethylamine or N,N-diisopropylethylamine are simply not basic enough."

Please check pKa values (Amines: aprox. 30, Alkynes aprox. 20 - 25). Why do you think, deprotonation does not occur? 213.188.227.119 (talk) 01:07, 4 January 2009 (UTC)
 * that statement is based on ref. 2. You also need to make the comparison with the pKa of the protonated amine not with the amine itself. V8rik (talk) 21:35, 4 January 2009 (UTC)

Working on major edit
I am planning on making a major edit to this article over the next few weeks as part of a project for a graduate chemistry course. Jcap17 (talk) 14:08, 21 October 2011 (UTC)

Initial comments:

The article is reasonably laid out, but still lacks major details.

Suggestions:

- The lead is nice and succinct. Instead of Cu+, how about Cu(I)? You might also want to indicate some standard conditions. Which reagents are used in stoichiometric quantities and which are used in sub-stoichiometric quantities? Maybe also give one or two sentences about why the reaction is important.

- The drawn catalytic cycle is very odd. Can you please re-draw it in a more conventional way using standard ACS settings in ChemDraw?

- Under the catalyst section, you don't mention any typical ligands. That might be useful.

- It may be worth noting that while the copper-free Sonogashira is quite reasonable, but palladium-free version is probably a fantasy.

- Homocoupling = Glaser coupling = bad

- You have a significant lack of examples and drawings. Please show more reactions! For example, you mention applications in natural products, but there isn't a single structure of a natural product there.

- The mechanistic details are scant, and that section could probably use some re-organizing. Maybe have one section that explains the classical mechanism, and then another that explains the evidence for it. What do you mean "major limitation of this cycle"? Does that mean turnover-limiting step? Does that mean it's a reason to question its validity? How do copper-free reactions replace the copper catalytic cycle? I.e., how do they work?

Eugene Kwan (talk) 19:35, 24 October 2011 (UTC)


 * and please include DOI's with citations? V8rik (talk) 19:38, 24 October 2011 (UTC)

Problems with recent edits
To Shwinn Ricci: I'm glad to see more work being put into this article! I think you are new around here, welcome! Some constructive feedback on this article:
 * 1) Many of the jpg files you have uploaded are pretty clearly taken from manuscripts directly, I'm pretty sure this is not okay and will get your images justifiably deleted. The ORTEP is clearly not your original work unless you got the cif file and made it yourself. You need to re-draw them in chemdraw, then convert them to svg (preferred) or png (okay if svg give you trouble). When you upload your own images, you must use the least restrictive license or it will be flagged.
 * 2) Your chemdraw images seem to be using the (terrible) default Chemdraw settings. Be sure to choose "File->Open Stationary->ACS 1996" so that you have reasonable bond lengths and font sizes.
 * 3) As mentioned above, references should conform to Wikipedia guidelines and include doi numbers for linking.
 * 4) I feel that a lot of the recent edits are hap-hazard and distracting. There are thousands of pages on the Sonogashira coupling reaction, this article should distill the important, general information into a readable, concise, clear document. More ≠ better. Think short, critical Angew. Chem. review, not long Chem. Rev.Dweix (talk) 03:02, 16 December 2011 (UTC)
 * the crystal structure should go but as it does not have a proper licence it will eventually be deleted. V8rik (talk) 23:15, 16 December 2011 (UTC)

Error
Trans-cis isomerization in the figure doesn't actually happen in the structure shown (Step D essentially does "nothing" as shown)

Should the R3NH2+ in the copper catallytic cycle not be R3NH+? — Preceding unsigned comment added by Eggilicious (talk • contribs) 12:04, 22 February 2012 (UTC)
 * Yes, I can confirm the error exists. Edit made here. We could fall back to the one that already existed V8rik (talk) 16:43, 22 February 2012 (UTC)

Amine free Sonogashira variant of reaction with TMS protected alkynes
Hi,

Recently, I have found some article that concerns synthesis of disubstituted ethynes by nonclassical Sonogashira reaction. This variant allows to use TMS protected alkynes (this kind of protecting group is not reactive in classic Sonogashira reaction), and it's free of amine usage. Ratio of Palladium catalyst to Copper(I) Chloride is crucial, and CuCl is added in molar quantities to substrates. This method allows to obtain symetrical and unsymetrical disubstitued alkynes in one reaction from aryl iodides and protected alkynes. I've tried this reaction a few times and yields were about ~70%.

Two examples of my own:

4-iodobenzonitrile + 1,4-bis(trimethylsilyl)-1,3-butadiyne > 4,4'-(buta-1,3-diyne-1,4-diyl)dibenzonitrile Y=75%

4-iodopyridine + 1,4-bis(trimethylsilyl)-1,3-butadiyne > 4,4'-(buta-1,3-diyne-1,4-diyl)dipyridine Y=82%

Here is the link to the article:

http://www.sciencedirect.com/science/article/pii/S0040402012004462

I think this method is worth of being mentioned in this article. English is not my first language, so I don't want to take this responsibility and add any content to this article.

Best regards,

A Leniak (talk) 22:22, 5 March 2015 (UTC)

=A major edit to update and repack the contents (Dec 2018)=

Hello,

I have decided to reconfigure the current design of the "Sonogashira coupling" wiki article, as to implement and update the latest discoveries in the field. Also some of the topics were repeated throughout the text and required reorganization in a more concise fashion.

Thus, the initial reaction scheme was changed to a colourized one to follow the colour theme through the whole document. It is also in the ACS style rather than a simple equation form.

The History section was updated to emphasize the reason why the alkynylations are termed "Sonogashira", despite using the original Pd/Cu catalytic systems. In that view, copper-free Sonogashira reaction could be as well entitled as the Cassar-Heck alkynylation.

Mechanism The mechanism scheme was generalized. Also the colour code was slightly modified to emphasize the origins of alkyl group. Cis-trans isomerization from former C to D was removed from the scheme since it is not exactly true for all the catalysts types (some bidentate ligands prevent the formation of trans-OA). The process is now just mentioned in the discussion. The end paragraph, discussing the different active catalytic species was incorporated into the "Pd cycle" discussion, since it is a crucial part in the OA formation – not all are formed in the previously depicted trans geometry and it is more correct to display it as LnPd-ArX.

Since the mechanism of the Cu-free reaction was recently discovered, it was included as a subtitle in this section.

Prior mechanistic discussion was removed from The Copper-free Sonogashira reaction section under Reaction variations. The contents were modified to just describe the reasons, benefits and drawbacks of this alternative coupling procedure.

Arenediazonium precursors section was moved from Catalyst variation to the Reaction conditions. Au/Pd is still mentioned under Catalyst variation and thus repeating of the topic is avoided.

Reaction conditions – sub-titles were introduced, namely Catalysts; Aryl halides and pseudohalides; Alkynes; and Bases.

Best regards,

Miha (talk) 13 December