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I am not very familiar with exactly how to add references on to wikipedia, especially if they are journal articles which leads me to why I am posting in here rather than just editing the page my self. The page states that the Witting reaction was first reported in 1954 it was in fact in 1953 in this paper: Wittig, G.; Geissler, G., Liebigs Ann. Chem. 1953, 580, 44. If anyone feels they can make the amendment in a neat fashion after checking that they agree I am correct please do. 86.147.208.59 ( talk) 11:47, 20 January 2013 (UTC)
Should we have a separate page for the Wittig reagent, or keep the information in this page? I am in two minds- it's nice to have all the information together, and clearly the Wittig reagent is pretty much always used for the Wittig reaction. At the same time this page will end up fairly long, and the section Wittig reaction#Wittig reagents could easily be made into a separate complete page once the structural information is added. There is already a short stub called ylide. What do others think? Walkerma 15:10, 23 May 2005 (UTC)
On another note, I noticed the first reaction image shows R3P... for the ylide and R3P=O for the product instead of Ph3P... and Ph3P=O. Are those 3 groups always phenyl groups in the Wittig reagent. If they always are, it might be worthwhile to change that R in the image to Ph. I think I'll do that while waiting for a response from you; then upload them if that's right. H Padleckas 01:57, 31 May 2005 (UTC)
One more note in the 2nd reaction image, the first 2 steps show the phenyls as PH and the rest shows Ph for the phenyls. I think I would have made it Ph all the way through. Also the labeling of the R groups is not consistent with the first image. I'll await for a response to see it that worth changing.
Otherwise, all in all, looks like the article is shaping up rather nicely. H Padleckas 01:57, 31 May 2005 (UTC)
I have added a bit more content. The Carruthers book states that R is nearly always phenyl, but then goes on to explain the reactivity of Wittig reagents that are derived from tetralkylphosphonium salts. We should probably amend the intro somehow to make it clear that we are using Ph because that is what is nearly always used. I will dig out some nice examples of the use, though ~K is welcome to do this instead if he/she wishes- I think his/her graphics are probably sharper than mine! Cheers, Walkerma 21:28, 1 Jun 2005 (UTC)
As you see below, the fact that phenyl groups are almost always used may have clouded our picture of the reaction. I think the fact is the reaction is poorly understood. Eugene Kwan 18:46, 17 December 2005 (UTC)
Hi there. I must dispute your mechanism for the Wittig reaction. There seems to be considerable evidence that there is, in fact, no betaine intermediates (JACS, 1990, 112, 3905-9). Oxaphosphetane formation from unstabilized ylides can be reversible for some aldehydes (Maryanoff et al, JACS 1986, 108, 7664.) while oxaphosphetane formation from stabilized ylides is irreversible (Vedejs, et al. JACS 1989, 111, 5861). Interestingly, when the syn oxaphosphetane is generated independently, the Z olefin is obtained. Also, if instead of using, say, triphenylphosphonium ylide, one uses a trimethoxyphosphonium ylide, poor E/Z selectivites are the result. A recent ASAP in JACS from Aggarwal addresses the origin of high E selectivity in stabilized ylides. I don't understand it very well myself, but it seems clear that the mechanism you've drawn cannot be operative. Comments? Eugene Kwan 09:11, 17 December 2005 (UTC)
I think we ought to have a separate page for the Horner Wadsworth Emmons reaction. I think it's not simply a more reactive alternative to the stabilized Wittig...I'm not even sure that's the case. There are a bunch of benefits, such as no triphenylphosphine oxide to remove, less epimerization, a wide variety of mild conditions, ability to get E or Z selectivity by varying the phosphonate ester type, etc. Also, the mechanism probably proceed via a betaine intermediate. I'm working on the aldol page right now, but when I'm done, perhaps I'll start a new page. Eugene Kwan 18:49, 17 December 2005 (UTC)
Sure, if I get around to it. I'm still working on a lot of stuff on the aldol page.
Eugene Kwan
00:33, 19 December 2005 (UTC)
This might be of interest: JACS ASAP: Reactivity and Selectivity in the Wittig Reaction: A Computational Study Raphaël Robiette, Jeffery Richardson, Varinder K. Aggarwal, and Jeremy N. Harvey Web Release Date: 27-Jan-2006; (Article) DOI: 10.1021/ja056650q Eugene Kwan 18:20, 27 January 2006 (UTC)
I've only ever heard of this being spelled "ylid". Is ylide just the American spelling or something? Aaadddaaammm 07:15, 29 October 2006 (UTC)
I agree, I'm a chemistry student in Scotland and I've only ever been taught that it is spelled "ylid". The page on "ylide" doesn't mention anything about alternative spellings either. 87.194.118.241 11:51, 9 March 2007 (UTC)
It's pronounced "yeah lad" —Preceding unsigned comment added by 143.167.201.212 ( talk) 19:48, 17 November 2009 (UTC)
I want to carry out this experiment in a test tube. Can this be available? Thank you! —Preceding unsigned comment added by Me3CBr ( talk • contribs) 15:10, 23 July 2008 (UTC)
The text says the reaction favours the E configuration, but the picture appears to show the Z form as the final product. —Preceding unsigned comment added by 93.97.76.185 ( talk) 20:42, 17 November 2010 (UTC)
31.11.20.64 ( talk) 17:41, 30 June 2018 (UTC) The identifier box uses an unsafe link to the http: version of www.organic-chemistry.org, although all pages are available under https. If someone knows someone who could fix this centrally, please contact him/her.