Wikipedia:Featured article candidates/Aldol reaction

Aldol reaction

I came across this article during random travels through the encyclopedia. The importance of this carbon-carbon bond formation reaction can hardly be overstated. All the important mechanisms and stereochemical models are mentioned; it had an external peer review a while back (see Talk:Aldol_reaction#Nature_errors_to_correct for that), and it is adequately referenced. Everybody please weigh in! Dr Zak 19:02, 22 November 2006 (UTC)

• Comment and minor object (as of now): more minor issues first: Preferably, the footnotes can be converted to the cite.php method described on WP:WIAFA and WP:FN. Also, the See also comes before References (WP:LAYOUT). Also note that there should be no spaces between punctuation marks and footnotes (ex. :[1] instead of : [1]).
• It would be very helpful to add a section which explains the entire topic in laymen's terms. Honestly, I can barely follow the first paragraph in the WP:LEAD (which, by the way, is too long according to WP:LEAD)

Not sure if anything can be done about that at all. This reaction is bread-and-butter for any chemist, but how do you begin to explain what carbonyl compound means to a layman? Dr Zak 04:08, 23 November 2006 (UTC)

• Also suggest a copyedit. I'm not too familiar with the terminology, so I'm not absolutively positive that the following are wrong:
  • If strong bases such as LDA are used, the enolate may be produced separately before the reaction, then an aldehyde slowly added at low temperature to produce the aldol product. Just read it out loud. Try rephrasing the last part of the sentence.
  • or ketones can also be deprotonate to deprotonated.

Done. Dr Zak 03:43, 23 November 2006 (UTC)

• • Not about copyediting, but I picked this up while reading: why is another molecule italicized? At first glance it looks like terminology.

This is because acid has a dual function: to catalyze enol formation, and to activate the carbonyl group of an aldehyde towards attack by the enol present in the equilibrium. Dr Zak 03:43, 23 November 2006 (UTC)

• • Also not about copyediting (wow, I'm easily distracted), but try laying Image:Enol aldol mechanism.png out better.

Can you explain how? I really like the layout of this - but then I drew it! I put in a lot of thought planning the layout to make it as clear as is possible. Did you want color added to the structures? If not, can you suggest a specific change to make it better? Walkerma 05:21, 1 December 2006 (UTC)

Not the image itself, I meant the layout of the image in the article (for example, see [1]). AZ _t 01:20, 2 December 2006 (UTC)

Still looks fine to me! Maybe it's different browsers. If it's just a layout issue - so can you fix it so it looks OK to you? Would centering it solve the problem? Walkerma 03:30, 4 December 2006 (UTC)

• • Otherwise, the mechanism can be regarded as the same. I plodded through the paragraph with this sentence, and I can't seem to understand what it is saying.

This is about different bases (hydroxide ion vs stronger bases). Agreed, that sentence is superfluous. Dr Zak

• • Enolization may be effected using a strong base ("hard conditions") or using a Lewis acid and a weak base ("soft conditions"): affected, right?

We are discussing what causes enolate formation, not what influences it, so "effected" is the right word. Dr Zak 15:07, 24 November 2006 (UTC)

"Effected" means to "bring about". It means, literally, "to have that effect". It is not the same as "affected". The word is being used in a precise and scientific manner. --Amandajm 22:15, 27 November 2006 (UTC)

• • Extensive studies have been performed on the formation of enolates under many different conditions. See Tony1's guide- here, we can eliminate many as redundant since we already know that extensive research was performed.
  • Despite the cost and being limited to syn adducts Un-parallel.

Reworded. Dr Zak 15:07, 24 November 2006 (UTC)

• • stereoarrays: syn selective: [30] and anti selective: Three colons in a row? 2 can go.
  • The methods described allow the synthesis of extensive polyketide stereoarrays to be assembled. Allow the synthesis to be assembled? AZ _t 01:08, 23 November 2006 (UTC)

Re-worded. Dr Zak 15:07, 24 November 2006 (UTC)

• Two of the references 23 and 25 are the same ! And 12 and 17 are the same.--Stone 10:01, 23 November 2006 (UTC)

This has now been fixed. Dr Zak 21:57, 28 November 2006 (UTC)

Sorry, I rarely do this, but I've decided to change my vote to an object. Features articles on complicated science topics do indeed need a simpler section for those who have had less experience w/ science. Ex. see Wikipedia:Featured article candidates/Photosynthetic reaction centre/archive1 (note that I was involved w/ the FAC, but I'm not trying to make a point). What would happen if this page went onto the Main page? I doubt that most people will be able to understand any part of it. At least, note where this reaction occurs (why is this reaction important to a layman?) and its significance.

Also, nice job rewriting the lead, but there are a whole bunch of typos in there; also, there are some references from the first couple of sections to the lead which no longer are applicable (ex: acidic or basic conditions, as shown above). AZ _t 01:20, 2 December 2006 (UTC)

I think the lead section is as uncomplicated as possible already. Any simpler, and it will have to say "the aldol reaction is important in chemistry". Frankly, I'm not sure the reaction *is* important to a layman, despite its role in biochemistry, or industry, or whatever. Does the layman care about the Battle of Austerlitz? Probably most people don't. I don't think it's the purpose of featured articles to incite the interest of the general public. Presumably the people who are interested will at least have a little background, and will understand some of what's written. From reading the criteria, it seems like you need it to be "well written, comprehensive, factually accurate, neutral and stable", with a good lead section, hierarchical setup, table of contents, images, and references. Now, I certainly think there's some copyediting that could be done, but it seems like the rest is there. I do take the point that the lead section may well be incomprehensible to a layman, but I can't see anything that could, in principle, be done about that. Maybe you could suggest some specific stuff which you feel could be done. I would add more about how it's used in industry or biochemistry, but frankly, I have no expertise in that area, so I really can't. Eugene Kwan 03:53, 2 December 2006 (UTC)

This article isn't about an object or concept that one might encounter in everyday life. Looking through the list at WP:FA if this were promoted it would qualify as the article most remote from everyday experience. I would go so far to say that it is impossible for a layman to understand the article; one would need to know about carbonyl compounds and their reactivity first, something not encountered at all in daily life. However, the sheer bulk of literature on the subject testifies to its significance, and as far as I am qualified to judge it is comprehensive and well written - in fact it is more complete than the textbooks on the market. As Eugene said, if there are any specific low points we can address them, but your main complaint seems to be that only chemists would be expected to have an idea what this is about. That's the nature of the subject. Dr Zak 04:30, 2 December 2006 (UTC)

I agree that it would be impossible for a layman to understand the article. However, there has to be some use for the reaction- it would hardly be comprehensive for an article on a reaction to only discuss the steps involved in the reaction. Perhaps add a paragraph somewhere about when this reaction is used. It is noted how certain methods are more industrially useful; we don't need to go in-depth about exactly how the reaction is specifically incorporated in industries, but we do need some examples of when this reaction is required. AZ _t 23:29, 2 December 2006 (UTC)

Well, the important feature of the aldol addition is that two stereocenters are set up in just one reaction step, and that the organic chemist's toolkit contains has means to set them up almost in any way that is called in the course of a multistep synthesis. You are right, this must go into the introduction, and perhaps we also need a landmark synthesis where aldol chemistry was used in the crucial steps. (I don't have time to hit the library before Monday, though!) Industrial applications - not sure that they are important - pentaerythritol and a couple of related compounds are so prepared, but the wide scope offered for synthesis of stereogenic centers is what gives this reaction its importance in today's chemistry. Dr Zak 03:47, 3 December 2006 (UTC)

I suppose when one asks "why is such and such a topic important?", one should also be asking "important to whom?". Now perhaps if you're an industrial magnate, the most interesting part of the aldol reaction is its use in industry, but if you're a chemist, it's cool because it's such a powerful reaction. Evans and many others have studied this chemistry in so much detail that polyketide synthesis has moved from "impossible" to "challenging", and now, "routine". Certainly, the cutting edge polyketides people are working on now aren't exactly "routine", but the point is that our understanding of this reaction is a big advance. Now, if I see an alkyl center next to an oxygenated center, chances are excellent that there's already methodology to make that stereoarray. If you were a chemist 50 years ago, it would have been a lot more difficult, if not impossible. Eugene Kwan 04:04, 3 December 2006 (UTC)

I've changed the lead a bit, per the suggestions above. Also, are the "C-alpha" and "C-beta" markings necessary? Sorry, Dr. Zak, I was editing at the same time you were, and I felt your statement was best included where I had it...I'm open to suggestions. Eugene Kwan 05:38, 3 December 2006 (UTC)

In the scheme you mean? Not sure, the idea was to make the nomenclature immediately obvious to the lay reader without anyone having to go to alpha carbon. I'd leave the stars in, though, to point out the stereocenters. As for the lead I would put the definition in the first paragraph, reaction partners in the second, and importance and synthetic applications in the third paragraph. There's some redundancy there right now. Dr Zak 05:50, 3 December 2006 (UTC)

Er...I'm not sure that's the best way to do it. But I'm leaving in the redundancy for now, and maybe others can take a look, and sort it out. — Preceding unsigned comment added by E kwan (talk • contribs)

I've rearranged the introduction a bit. Dr Zak 20:45, 3 December 2006 (UTC)

Hi everyone...I contributed the majority of the material on the page, and I've just added some new stuff. What is the current feeling about the article? Eugene Kwan 05:32, 28 November 2006 (UTC)

Support with comments.

• Line diagrams are best displayed in SVG format, you have a mix of PNGs and GIFs.

*You need to explain the Ireland model in text.

• • Has been addressed

*All the references past the Crimmins thiazoldinethione reference need formatting to the same reference format as the earlier references.

• • Has been addressed
• More information on uses in industry would give this article more balance. TimVickers 23:55, 28 November 2006 (UTC)

I'm afraid I don't know anything about these graphics format. I drew everything in Chemdraw...perhaps I could re-export them? I agree with the next two points. The fourth point: as a graduate student in the Evans group, I'm afraid I don't know much about industrial uses...perhaps someone else can add something. Eugene Kwan 00:20, 29 November 2006 (UTC)

• Support, the chemistry is very advanced and insofar as I am qualified to judge very accurate, the references have been updates nicely to wiki standards, the intro is aimed for non-technical readers as it should be. My only concern is the size (already 35KB): some segments could possibly be spinned of to separate articles for example two named reactions Mukaiyama aldol addition and the Hajos-Parrish-Eder-Sauer-Wiechert reaction and the Evans ligand. What remains unclear is the use of syn and anti in the text, it is used in a different way than syn addition would expect. Regarding the images: I prefer to have the images in png (rescalable!) and not gif, I do not see any advantages to svg though V8rik 17:39, 29 November 2006 (UTC)
  • As for the nomenclature to describe the relative stereochemistry at α- and β-carbons, Evans uses syn and anti in his papers. This isn't the same as a syn- or anti-addition, of course, and in older papers one sees erythro and threo from carbohydrate chemistry. Since the main author is from the Evans group I'd say to let him use what he's familiar with. Dr Zak 23:57, 29 November 2006 (UTC)

Hey guys, thanks for the support. I think I've done as much as I can. On my computer, the graphics look nice, and it would take a lot of effort to convert everything to something else, which, IMO, would look the same. I'll leave it in your hands. Eugene Kwan 20:00, 30 November 2006 (UTC)

The image policy is explained here. Wikipedia:Preparing images for upload PNG would probably be easy enough, since that doesn't require a program that can rasterise the images. TimVickers 20:19, 30 November 2006 (UTC)

• Support. I agree with two points that V8rik has made above. The article is long and segments can be put in different articles. Additionally, the images as PNGs are just fine. There is no advantage to using SVG for chemical schemes. In fact, I would say there are plenty of problems. But I digress... The article should be a featured article. ~K 05:07, 1 December 2006 (UTC)

• Support: (Disclaimer: I was a significant contributor to this article). I've given several talks on Wikipedia and I've always used Eugene's section on the Evans aldol as an example of what I think is excellent quality material on Wikipedia. The more advanced material is better and more up to date than you will find in many textbooks! It's about time this page got the star it deserves - I think the recent editing/peer review has tweaked the article enough to bring it up to FA standards. I don't think you could rewrite the intro in more basic language. Regarding SVG, we have had problems with SVG files in organic chemistry articles, they have usually given lower image quality than PNG or GIF. Walkerma 05:21, 1 December 2006 (UTC)

Hey, that's great. I don't mind at all if you guys think it'd be better to cut it up into smaller articles. I'm not very adept at Wikipedia, though, so perhaps I can leave that to you? Also, is it worth my time to convert the many chemdraw files I have to PNG instead of gif? That'd take quite a while, but I'll do it if it's necessary. Eugene Kwan 06:20, 1 December 2006 (UTC)

• Object with regrets. An article about the aldol reaqction should explain why β-protons are (relatively) acidic: without this information, a student chemist cannot understand the excellant chemistry which is described in the article. I would favour a split, taking some of the more intricate applications into seperaqte articles: this should be fairly easy, given the depth of coverage which this aritcle already gives them. There is obviously an FA in here, but it is not there yet. Physchim62 (talk) 15:59, 1 December 2006 (UTC)
  • I would disagree. This article is about a certain reaction of carbonyl compounds; the fact that carbonyl compounds are CH-acidic has its place in the article on carbonyl compounds. (Surprising to see that we haven't got an article on CH acidity yet! Dr Zak 16:08, 1 December 2006 (UTC)

• • (rare edit conflict!) Valid points: I volunteer to do two tasks: reinforce the carbon acid article: why hydrocarbons can be acidic etc. and a table with pKa values and make sure the Aldol article links to this page in a prominent way. Also I will float the Mukaiyama aldol addition as a separate page. I will also try to update the DOI's in the references. I think the image issue is solved, no advantages for SVG. Only change gif to png when you have the time (not a must-be for FA status). Thanks Eugene for providing the explanation for syn/anti in the text, this issue is solved! a great help. V8rik 16:13, 1 December 2006 (UTC)

Agreed, I don't think a detailed discussion of acidity belongs in this article, any more than a detailed discussion of how artists use paint belongs in an article about Monet. Eugene Kwan 16:34, 1 December 2006 (UTC)

Sorry Physchim62, but I agree with Dr. Zak here, this is an article about a reaction that uses enolates. A detailed description of C-H acidity belongs in enolate, which should probably be split off from enol. Admittedly we have a little on the stereo/regio chemistry of enolate formation in this aldol article, but that is because it has great relevance in determining which aldol product is formed. If v8rik strengthens the carbon acid article, that should suffice. Walkerma 21:20, 2 December 2006 (UTC)

• improved carbon acid article, added DOI's, Mukaiyama aldol addition now a separate header ready to float and explained a bit on dibutylboron triflate. Some bits in the enolate section should belong in enolates because enolates are used in more reactions than just Aldol. Even Evans' oxazolidinone chemistry is not unique to Aldol as it has other uses. Comment to AZ: FA perhaps too technical for main page (it should go for main page) but science portal also has FA V8rik 23:20, 2 December 2006 (UTC)

• Comments. In the lead, can we have just a tiny glimmer of information for non- and semi-experts as to the significance of the topic in the wider world? It's about catering for WP's wider readership at least a little, and more importantly, selling science to the policy makers. Minus sign should not be a hyphen (–78 occurs twice). An en dash is OK (–). An en dash is required for "carbon–carbon", so you could pipe the link to the wrongly named article. "The Evans' acyl oxazolidinone method." Why the apostrophe? It probably needs a careful copy-edit to weed out little glitches, although it's not too badly written. Tony 12:35, 4 December 2006 (UTC)

  To answer that question, the apostrophe is used for that sentence because the last name of David A. Evans ends with an S. The -78 thing seems to have been fixed already. How about the little mentioning of pharmaceuticals in the beginning, the stuff about polyketides? --HappyCamper 14:20, 4 December 2006 (UTC)

  Eugene had had a go at the introduction the other day, and he improved it much.[2] The article is very clear about the relevance of the reaction (emphasis mine): "Structural motifs derived from aldols are especially common in … natural products from which many pharmaceuticals are derived … . Extensive research on the aldol reaction has produced highly efficient methods … . The synthesis of many polyketides, once considered nearly impossible, can now be performed routinely on the laboratory scale, and is approaching economic viability on a larger scale in some cases … . In the aldol reaction two stereogenic centers … are set up in one single reaction step, making this reaction an attractive choice for the synthesis of complex molecules with many stereocenters. … Stereoselective synthesis is of considerable interest to the pharmaceutical industry, since the stereochemical configuration of drugs can greatly impact their biological activity." A large amount of effort has been devoted to this reaction by organic chemists and the methods that are now available are incredibly powerful. Of course reading Wikipedia isn't the same as taking two or three years of chemistry at uni level, but all the relevant keywords are linked within Wikipedia, and the articles linked are of good quality. Dr Zak 15:06, 4 December 2006 (UTC)

Is there supposed to be a red link for Mukaiyama? So what are our outstanding issues? Eugene Kwan 02:51, 5 December 2006 (UTC)

• • there is not, took care of it V8rik 21:16, 6 December 2006 (UTC)
• Support. This article really has more detail than many textbooks and IMO is one of the best examples that Wikipedia has to offer in terms of comprehensive, well-referenced articles in the area of chemistry. The main thing I would add is some mention of the biological role of the aldol reaction, specifically with a link to aldolase. Also, a link to pentaerythritol wouldn't hurt, considering that it is a major industrial application, at least when measured in terms volume (253,000 tonnes in 1989 according to Kirk-Othmer). Itub 18:42, 5 December 2006 (UTC)
  • took care of it V8rik 21:16, 6 December 2006 (UTC)
• Support. As much as I dislike Org. Chem. this is a fascinating article. Congratulations to the editors. -- Rune Welsh | ταλκ 18:20, 6 December 2006 (UTC)

Summary?

• As far as I am concerned all of the above reservations have been discussed and where appropiate taken care of, so our slate is clean. If somebody's considerations have been neglected please restate them here, this will help to keep the discussion focussed, thanks in advance V8rik 21:16, 6 December 2006 (UTC)