Talk:Atropisomer

It is possible to separate certain atropisomers by normal phase flash chromatography. This was true of the atropisomers generated in the various total syntheses of vancomycin. -SynChem --140.163.191.19 00:20, 13 July 2006 (UTC)

Peer review and responses during the educational assignment in Fall 2013

Peer Review by kmk982013:

Content The introduction section is good. It does seem have a lot of scientific terms and may not be entirely accessible to the general public. Maybe explaining terms in a more general way would help. Also, there is a lot of information that could maybe be taken and put into another section later on in the article. For example, the 3 factors that lead to stability could maybe be placed into their own section with explanations and maybe figures, if those really are 3 important factors when discussing atropisomers. Otherwise, the rest of the sections seem to be of a good length. I also believe that the addition of the stereochemical assignment section was a very good way to help the public understand how the two atropisomers are defined. I think that a good job was done with linking terms to other Wikipedia pages. However, in the introduction, basicity is spelled wrong so it is not linked properly, and in the synthesis section, Ullman Coupling does not have its own page, so the link is not necessary. Also, in the Biological Relevance section, the scientific name of the organism where vancomycin was isolated does not have a page, and doesn’t need to be linked either. Most all of the examples used in the article are very good and back up the information presented. However, the axial chirality switch example seems out of place to me for some reason. I know it was included in the article previously, but I feel like it might be able to be taken out. Overall, I think a good job was done to explain this article without overlapping to any of the linked pages in any particular section. Figures Most of the figures in the article are perfectly fine. Like stated previously, I believe that maybe a few more could be added either in the introduction or in a separate section if information was moved from the introduction, to help explain that information a little better. Also, the figure that is in the introduction could use a caption or sentence of explaination. In doing a little research, I was assuming this was the original molecule that was found to be an atropisomer, so maybe when that is mentioned in the introduction, something like See Figure could help if this is the case. The only other note is that the figure in the synthesis section seems smaller than all the others, I don’t know if this is an issue at all. It is also the only figure that has a caption contained within it, so it does look different, but that may not be a bad thing. References There are 8 new references that have been added, so that requirement is covered. The newly added sources appear to be almost all journal articles, so maybe another book source would be a good addition if information can be found. Overall Presentation Overall, I think that the article as a whole has been adjusted very well. Several new sections were added that help to explain not only the definition of atropisomers in general but also the extention into synthesis and natural products. Most advice for changing the article has been stated above, such as reducing some of the scientific terms in the introduction section as well as possibly reducing the size of the introduction section overall. Otherwise, a good selection of information seems to have been added in addition to what was already in the article. Also, the article is now more organized and has a better flow through the sections. Only a few figures could maybe be added to help clarify a few points, but the present figures are good to leave in place. The references added seem to be helpful, with maybe the addition of another book source to make sure that non-journal sources are fully represented.

Peer Review by AimNature

Introduction Introduction is overall good but as a non-specialist reader I think the opening paragraph can be better arranged. It will be better to talk about rotation half life as defined by Oki in the first paragraph and also mention if there are other views on half-life as well. It will also be good to give chemical structure of 6,6’-dinitro-2,2’-diphenic acid (or the figure is that of this molecule??). The three basic factors for atropisomers can be discussed in a new paragraph or if they need more detailed discussion, then a separate section would be better. I also think the scope of atropisomers like in drug design or natural products can be added in short to the introduction. A reader generally doesn’t read beyond the introduction and it is good to provide him a general factual list here. A few edits required in this section: “…the size of the van der Waals of the particular substituent of interest” and “…to simply rotation due to thermal energy.” need editing.

Other sections It is a good move to add a section of stereochemical assignment in the page. It will help readers to have an idea about determining the axial stereochemistry of such compounds. In synthesis section, examples (through figures) for the two methods of achieving diastereoselective coupling (the use of a chiral bridge that links the two aryl groups or through the use of a chiral auxiliary at one of the positions proximal to axial bridge) can be helpful to understand the point. The third section ‘Scope’ is well written and the first reaction illustrated is nicely explained. In my opinion, a separate heading for “asymmetric catalysis” is not required. The section on 'biological relevance and natural products' appears to be short and ‘biological relevance’ point seems to be weak- is it that one atropisomer plays a specific role compared to the other? Are there examples for such atropisomers? Drug design section is well written and appropriate amount of information has been provided.

Links to other Wiki articles The article provides links to other Wiki articles as and where necessary, though I found links to pages which do not exist: basicity, Ullman coupling and Kniphofia foliosa. Also, few links lead to pages which are not directly related to the topic or chemistry as such. Like in introduction section, link to “optical” leads to a page on optics. This doesn’t seem appropriate here.

Figures The figures are well drawn and are of good quality. However, a caption would be greatly helpful. A reader would want to read the caption and understand the figure rather than search the text.

References Fourteen references provided fulfill the requirement and appear to be apt and provide a good lead to the readers. However, majority of the references are research articles. Only one book has been referenced to in the text . It will be better to add a book source or a review article on the topic.

Overall Presentation The article is well written and expands on the previous page. A good amount of relevant information has been added. The section on synthesis and scope provides in-depth knowledge about atropisomers which would be useful to readers looking for information beyond the basic definition. The flow and the article outline are good. However, I feel the introduction paragraph can be better rearranged. Other sections are well written and the suggestions provided above will help to make this article better. Figures are clearly drawn; adding captions will drive home the idea better. While the references added are appropriate and helpful, adding another book source might be useful.

AimNature (talk) 04:48, 4 November 2013 (UTC)

Suggestions from ChemLibrarian (talk) 03:05, 5 November 2013 (UTC)

1. This sentence in the introductory paragraph needs a citation. "but atropisomerism was first detected in 6,6’-dinitro-2,2’-diphenic acid by Christie in 1922"

2. I see that all your images do not have a caption. It's better to add them so that you can refer to them in the text. For the name of a structure, it's better to put it in the caption instead of putting it inside the image.

Additional Comments

UMChemProfessor (talk) 20:03, 5 November 2013 (UTC) The Christie reference was lost from the original site. Please re-add it to your site. The introduction does seem long for the topic, consider moving some of the information to another section. Overall, the additions look great and I agree with the peer reviewer and ChemLibrarian comments.

Response from Authors

Introduction The introduction was reorganized and certain information that was in the original site that we felt was irrelevant, confusing, or not cited, was deleted. In addition, we moved the section about important examples of atropisomers to the scope section that goes on to talk about asymmetric catalysis. We decided to keep the 3 important factors in the intro because we felt there was no better place to put it and that it was an important point.

Other Sections The section on stereochemistry was unchanged except with the edit of the figure. In the section on synthesis, we added a new reference, included a new figure that explains diastereoselective and enantioselective synthesis. Under the scope section, we deleted the chiral switch example because it was too specific and not very relevant. As far as making some sections more accessible, we eliminated the more confusing examples to help make the page clearer. We also tried to make our sections as clear as possible. Because we wanted to keep the intro as short as possible, we did not add a short section about biological applications because our hope is that they see that those sections are available later in the page as seen in the table of contents.

Links We fixed the links, thanks for the comment! We also fixed the typos and grammatical issues that were noted.

Figures The figures were edited to add captions to make it easier for the reader to relate the text to the figures. New figures were added in the synthesis section to better illustrate the explanation.

References We added the reference by Christie in the introductory paragraph. In the synthesis section, we cited a book on biaryl coupling, which helps to fulfil to the book requirement.

Thanks so much for the comments! We hope the page reflects them and is improved.

Mechem13 (talk) 19:08, 9 November 2013 (UTC) Chemumich (talk) 19:09, 9 November 2013 (UTC)

More comments

Hi, here are some more comments. Some of the links go to disambiguation pages, eg ortho, meta, and Hammett. You can use this form: [[arene substitution patterns#Ortho, meta, and para substitution|ortho]] giving ortho. There looks to be no page for Hammett plot but there is an article on Hammett equation. So you could pipe the link as in [[Hammett equation|Hammett plot]] or you could just use the red link and hope someone write about Hammett plot later. There could be more articles potential written and linked such as hindered rotation. Graeme Bartlett (talk) 01:38, 10 November 2013 (UTC)

Significant cleanup done to article

Amides that are substituted at the R3 position allow for control over atropisomers.

…in particular to the lede, and to the image organization (including changing positions and creating a gallery), so the enormous white space of the all-centered images is now gone. The issue with the lede being long needs to be addressed, but the current problem is that there is lede content with citations that does not appear in the main article. Migrating material from lede to main article is a job for another day.

Note, the earlier lede has several significant errors, including assigning the connecting bond of atropisomers as sp2-sp2, misstating names, omitting bibliographic detail, hashing the description of the methods of study, etc. If you choose to edit or revert this, bloody well do it carefully, or you will be returning a mares nest of mistakes.

Finally, one image just did not seem to fit—the content of the image is chemically minimal, and its integration into the text was poor. The wording can be improved, and/or it can be re-incorporated into another image with white space, but as it is, it does not fit into the article. Here it is, for later reference:

All for now, Le Prof Leprof 7272 (talk) 23:57, 12 June 2014 (UTC)

Inconsistency between

…stereochemical nomenclatures in opening figure and in Stereochemical assignment sections need to be reconciled—Sa and Ra, versus "P for clockwise and M for counterclockwise". Le Prof

various problems

In the Determining Stereochemistry in Atropisomers figure the clockwise arrow is in the wrong place - it should go from A to A' instead of from B' to A. In the Two Examples of Atropisomer Synthesis there is no explanation of the *. If it is supposed to mean chirality there should not be a * at the Y on the left side. In Natural products, drug design there should be a period or semicolon between "axis" and "in neutral aqueous". 69.72.92.85 (talk) 07:25, 21 January 2015 (UTC)

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Revision of Feb, 2019

I removed this paragraph because I couldnt figure out what it means. It always worries me when a statement has the phrase "Chemists [or researchers, physicists]" do this or that. "Another method of synthesizing atropisomers is through the use of aromatic amides and thermodynamic control. By utilizing the planar rigid amide bond as seen in amino acids, and adding larger groups to the ortho position, chemists have been able to synthesize single atropisomers. Since atropisomers are thermally dependent, the thermodynamic control allows for selective synthesis under optimal conditions Clayden, Jonathan (2004). "Atropisomers and near-atropisomers: achieving stereoselectivity by exploiting the conformational preferences of aromatic amides". Chemical Communications (2): 127–135. doi:10.1039/b307976g. PMID 14737515." --Smokefoot (talk) 13:03, 5 February 2019 (UTC)

"The importance of atropisomers arises to significant degree because with sufficient stability of a conformer, they can display axial chirality (planar chirality). " They exhibit that chirality regardless of the barrier. Jeesh.--Smokefoot (talk) 13:11, 5 February 2019 (UTC)