Talk:Endiandric acid C
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Mistakes corrected in Total Synthesis section BUT ERROR REMAINS IN ORIGINAL TS IMAGE
[edit]Mistakes corrected included the description of the cyclizations (order, types). In essence rewrote the section, to accurately describe the original report and the Figure. However, note, there is still a significant mistake in the major Figure—an "X" is missing, and a pendant group was prematurely introduced, instead (see also hidden text in article). In doing the edits I found and added a second supplemental Figure to clarify the order and types of electrocyclizations involved. While the draft is improved, it is not to standard (second half of synthesis description is abbreviated, awaiting Figure error correction). See how this fits. Cheers, Le Prof Leprof 7272 (talk) 15:33, 10 June 2014 (UTC)
Mistakes corrected in image and text
[edit]Per the Edit summary, I "photoshopped" and reuploaded the original synthesis figure to remove the prematurely added diene, and to add the missing needed "X" group. At the same time, I have fixed a good part of the text errors, as noted here, in this discussion moved from V8rik's Talk page:
Re: the Endiandric acid C article, I had to show up here to invite you to that article, or so I thought. (We can move this discussion, there, if you wish.) I will, as you propose, have a look at the JACS article, and I can pull the article image and make a photoshop correction (all I would have time for). Later... have a look at the original description:
"K. C. Nicolaou’s group successfully synthesized compound 1, in 1982 using a series of sterocontrolled electrocyclic reactions. They observe that the product looked like multiple endo-adducts resulting that came from several Diels-Alder reactions. They attempted to synthesize endiandric acid C from an acyclic symmetric diacetylenic diol precursor 14, which they hydrogenated using Lindlar catalyst to give 15. Compound 15 then goes through intramolecular [4+2] cycloadditions, 6π disrotatory, and 8π conrotatory cyclization [note the misordering of these three steps; Le Prof] to give compound 17, bicyclic diol. They then silylated compound 17 and reacted it with sodium cyanide and HMPA to give the cyanide intermediate 20, [note omission of iodoetherification; Le Prof] which was then hydrolyzed to the aldehyde form 21. [note omission of reduction; Le Prof] Condensation of 21 gave the methyl ester compound 22. [note omission of steps here to the end; Le Prof] They reacted the methyl ester with the same reagent as intermediate 17 to give the methyl ester form of compound 28. They then treated Compound 28 with a lithio derivative of diethyl cinnamylphosphonate at -78 degrees Celsius, in THF for 15 minutes to give endiandric acid C 1."
As I said to this fellow editor, my description of the synthesis is not yet good, but it does correct this earlier content, which, esp. with respect to the cycloadditions and completeness, was substantially incorrect/flawed. All for now. Cheers Leprof 7272 (talk) 01:05, 19 June 2014 (UTC)