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Tough Synthesis

  1. Jun 9, 2005 #1
    Hey y'all

    I'm wondering whether it's possible for the following synthesis to occur and how?:

    http://harishkukreja.neargeek.net/Synthesis.jpg

    The thing is, after bashing my head against it for about 2 hrs - I've really gotten nowhere :cry: . A few of the rxn's we're allowed to use are:

    Hydrogenation (except you can't undo it :grumpy: )
    Halogenation + De
    Hydrohalogenation + De
    Oxidation (KMnO4)
    Ozonation (O3)
    Esterification
    Amide formation
    Reduction (LiAlH4 and/or NaBH4).
    Hydration + De (H2SO4 conc/dilu.)

    Using dehydration + 2*oxidation + esterification I can change the double bond to the bottom chain. using a similar process also yields the top (though in an isomer form). I'm however badly stuck when dealing with the middle section - further the double reactive sites are also bugging me - and blocking isn't really helping me.

    Any help would be appreciated and I will worship you forever o:)
     
  2. jcsd
  3. Jun 11, 2005 #2

    GCT

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    How about cleaving the double bond first, through oxidation. You'll have two carbonyl sites. Note that the left carbonyl created from this is part of an enolate derivative. Using a suitable base, perform the intramolecular condensation reaction, the alpha carbon will react with ring carbon #3 (the other newly formed carbonyl group). This will give you the exact ring structure you need. We'll go on from here.
     
  4. Jun 12, 2005 #3

    GCT

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    I'm just going to clarify a bit more...KMn04 oxidative conditions, claisen condensation, and we can go on from there....if you're still around
     
  5. Jun 12, 2005 #4
    I'm sorry for the delay - forgot I posted the question on the site :rolleyes:

    I figured it out (double checked with an independent source) - and I'll post it as soon I have access to my scanner (~Monday). Turned out to be relatively easy after the 2 tricky initial steps. In total there are 12 steps to the synthesis. I was told there were would be about 10-15 depending on the way one would go about it - so I'm happy with the result. If you can do it in less than 10 I'm interested :cool:

    Thanks for your help though.
     
  6. Jun 13, 2005 #5

    GCT

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    yeah, be sure to post the results, as I'm sure that many here are interested, I want to see if you're first two steps corresponds with mine.
     
  7. Jun 14, 2005 #6
    Here it is - just in skeletal format after dashing it off in a few minutes. If you spot any error, chalk it down to being in a rush - unless of course it's a major error, then please do tell. Ignore the term "possibility" - the synthesis continues from the last diagram to "#1" onwards (I just got lazy to draw the rings for each). See the first message for the inital and final diagrams.
     

    Attached Files:

  8. Jun 14, 2005 #7

    movies

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  9. Jun 14, 2005 #8
    We were never taught or exposed to Bredt's rule in class (lowly highschool kid) - so thank you for pointing that out. What would you suggest I do to rectify the situation?
     
  10. Jun 15, 2005 #9

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    I dunno. It's a tough question. I came up with an very different route from yours which takes 7 steps, but there are one or two steps that I don't really like myself.

    I can't think of an easy solution to your dehydration problem though. Sorry.
     
  11. Jun 15, 2005 #10

    GCT

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    since when did they start teaching organic chemistry in high school? I'll try taking a stab at this problem when I have the time.
     
  12. Jun 15, 2005 #11
    @ movies: could you please post your 7 step one - would like to see it (don't personally care if it works or not - just would like to learn something from it). Furthermore, just talked to my teacher, apparently he doesn't care about the violation - didn't even expect anyone to find out that problem.

    AP chemistry class - and the teacher is a bit of organic junkie - apparently it was what he did for his masters.
     
  13. Jun 16, 2005 #12

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    Alright, just don't go trying to pass it off as your own work. ;D

    I'd bet you've never even seen 4 of these 7 reactions before.

    The problems I see are with the isomers in the Baeyer-Villiger oxidation (it'd probably favor the undesired product) and with saponifying the lactone without saponifying the methyl ester. It might work though....

    I hope it's helpful to you.
     

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