Home » Still In The RBF

Platensimycin   

14 April 2007 18,728 views 28 Comments

Nicolaou, Tang and Wang. Chem. Comm., 2007, Advance Article. DOI: 10.1039/b704589a.

And again! This second publication (the third is due very soon…) by Nicolaou is another formal synthesis, actually going to the same intermediate that Snider did in the last post. Actually, looking at these two papers, alarm bells started ringing, as the retrosyntheses are not dissimilar:

platensimycin_4.jpg

Now I’m not trying to say that there was any foul-play here – just that this strategy seems quite popular! The interesting bit, I guess, is then the synthesis of that decalin, which thankfully uses an entirely different approach. The got to a quite complex intermediate very quickly by just doing a pair of enolate alkylations. With a few functional group transformations, they were then set for the most interesting reaction in this paper:

platensimycin_5.jpg

Now that’s a nice Stetter reaction! They state that they tried a number of carbene-based catalysts, but found that the triazole catalyst shown was optimal. I noticed that the catalyst has a per-fluoro phenyl group bolted-on – does this mean they could use Curran’s fluorous phase chromatography to separate it with ease? Anyway, it’s certainly a sweet method to put that system together.

I’ll blog the asymmetric synthesis shortly…

1 Star2 Stars3 Stars4 Stars5 Stars (No Ratings Yet)
Loading ... Loading ...

28 Comments

  • diketene says:

    The DOI is not active. I can not check the paper. But are you missing a double bond in the last reaction?

  • Tot. Syn. says:

    I copied the DOI’s from the paper – dunno why they don’t work. I think the Angewandte (the asymmetric paper) isn’t online yet… Thanks for the correction – double bond added! I hope you all like the new name for this blog…

  • Tynchtyk says:

    Totallysynthetic was much more beautiful.
    It’s KCN’s fault that your blog became Totallyplatensimycin :)

  • aa says:

    KC is surely m;lking this for all its worth.. i’ve never seen anyone else publish 3 tot syns of the same molecule in 6 months… why no chiral stetter reaction? Between Rovis, Scheidt, Bode and Enders this should be a pretty easy transformation by now

  • TWYI says:

    Look at the azmount of work KC published on diazonamide. Two total syntheses and I think 3 JACS on the work towards the old structure.

    5 JACS/Angewandte on one molecule.

  • ultradragoon says:

    I bet they have tried the assymmetric reaction on the tricky stetter reaction but just cannot get the good result. Since assym-style stetter is really worth another methodology paper using this ligand.

  • kiwi says:

    You aren’t actually derek, because you clearly have no idea what is actually said in that column. To summarise, read the last para.

  • Tot. Syn. says:

    #8:

    “80.254.67.236 is from Switzerland(CH) in region Europe”

    I’ll skip the rest of the details from the IP address trace-route…

  • Ok, It is me. The fake Derek is right. I hate it.

    Arkansas Rules!

  • Tot. Syn. says:

    “81.169.137.209 is from Germany(DE) in region Europe
    TraceRoute to 81.169.137.209 [anonymizer.ccc.de]”

    Interesting…

  • earth23 says:

    lol, am I the only one that finds traceroute data in a synthetic blog hilarious?

  • LUMO-HOMO says:

    This should be the THIRD in KCN lab.

  • TMS says:

    Is the first fake Derek Lowe someone posting from Burgenstock?? The world center for stereochemistry this week

  • milkshake says:

    there is a sense of a time-loop here – a nice cagey molecule and author though

    I wonder if the Stetter cyclization precursor here could be obtained by ferricyanide-oxidation of the 4(p-hydroxyphenyl)-1-siloxy-butane in presence of 2-bromoallyl silane.

  • DaveB says:

    KCN article has been posted:

    The link was missing a period in the DOI#. I believe this was also missing in the ChemComm article references.

    http://dx.doi.org/10.1002/anie.200700586

    I’ve enjoyed this page over the past few months.

    Cheers

  • XBOX says:

    The first sentence in the new Angewandte article shows that KC has a sense of humor ;)

  • ddd says:

    we all made a bterrible life choice :)

  • [...] Anyway, if you’d like to follow all the cut and thrust of platensimycin syntheses, everything you could possibly need is explained and discussed at the superb Totally Synthetic.    [...]

  • carbazole says:

    Has anyone ever done the Nicolaou-Baran enone-to-dienone oxidation? I’m trying to make a dienone, and the Saegusa-Ito works, but I’m still getting some SM back and it’s inseperable. I’m trying the IBX one now, just wondering if there are any hints anyone can give me. Not having experimental sections in papers is just wrong, especially at this point in time! It’s not like it’s wasting journal space. All I want to see is their exact conditions for that step, because it’s fairly early, so hopefully it works well.

  • hoodsash says:

    another….

    Org. Lett., ASAP Article 10.1021/ol070848t S1523-7060(07)00848-6
    Web Release Date: May 10, 2007
    Copyright © 2007 American Chemical Society

    An Expedient Enantioselective Strategy for the Oxatetracyclic Core of Platensimycin

    Krishna P. Kaliappan* and Velayutham Ravikumar

    Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai, 400 076, India
    kpk@chem.iitb.ac.in

    Received April 11, 2007

  • TWYI says:

    no 23, is it not in the supporting info?

    PS more platensimycin out recently, biologically active adamantyl analogues.

  • F-Blog says:

    Possible Fluorous Separation in Platensimycin Total Synthesis?…

    In a post reviewing work done towards a total synthesis of Platensimycin, Paul Docherty of TotallySynthetic.com wonders if a fluorous separation could be used to remove the catalyst in this reaction:

    They state that they tried a number of carbene-base…

  • Lloyd-Harrisonw says:

    If you’re looking for tamiflu for the current swine flu situation, please contact us by email at:
    tamiflusource@gmail.com]tamiflusource@gmail.com

    we have currently 28427 units in stock,
    but supplies are going quickly so don’t delay!

  • Manish Sharma says:

    23th May 2009

    Respected Sir,

    Sub: Request for providing Platensimycin sample for research studies

    With due respect and regards, this is in response to your research article “An Expedient Enantioselective Strategy for the Oxatetracyclic Core of Platensimycin” ; I undersigned is a Research scholars at Department of Zoology, University of Delhi, India; working on In vitro culture studies and want to validating effect of Platensimycin.

    We would be grateful to you if you can provide us with few milligram pure form sample of the same for our research studies.

    We sincerely thank your kind help and sincerely acknowledge your efforts. Look forward for your positive response.

    Thanking you,
    Sincerely,

    Manish Sharma (manish24jan@yahoo.co.in)
    Research Scholar,
    C/o Prof. V.K Bhasin
    Research Lab (Room No.119)
    Department of Zoology, University of Delhi
    Delhi – 110007, India
    Ph. – +91- 09999319075