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why can't this be diasteromer?

Discussion in 'DAT Discussions' started by joonkimdds, Dec 25, 2008.

  1. joonkimdds

    joonkimdds Senior Member
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    [​IMG]
    It has two chiral carbons (both carbon that are attached to Br).
    Can't this be diastereomer?
     
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  3. sciencegod

    sciencegod Super Member
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    don't know what your asking. this molecule will have a enantomer and a diastemor.
     
  4. doc3232

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    You need to show us another molecule. Then we can say whether they are diasteromers of each other.
     
  5. joonkimdds

    joonkimdds Senior Member
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    This is from Destroyer #33.
    It asks which produces two diasteromers.
    Reactant was cyclopentene + Br2 and what I drew is the product of that.
    and it's not the answer meaning this can't form diasteromers.

    The answer says this will have an enantiomer only.
     
  6. 5HTburb

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    The example you put up show a molecule that is (1S,2S), and since Br2 adds in anti fashion the other product (entaniomer) would have a (1R,2R) absolute configuration. I could explain it more but simply add Br in anti fashion across the double bond, assign your priorities and check for R and S. Counter clockwise S, clockwise R (if H is not in the back switch it.) Post if you are still confused. I hope this was somewhat helpful. Or I may not completely understand what you are asking
     
  7. joonkimdds

    joonkimdds Senior Member
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    5HTburb//

    Do you think the product I drew can have a diastereomer? because DAT destroyer says it can have enantiomer but it cannot have diastereomer.

    I think anything with 2 chiral can be diastereomer so I am confused why this isn't the answer.
     
  8. zuma35

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    The molecule in question can have a diastereomer. What the DAT Destroyer is saying is that the product of the reaction will not yield two diastereomers. It will only yield two enantiomers because the Cl2 adds anti.
     
  9. 5HTburb

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    Yes the molecule you ask about as previously stated is

    (1S, 2S)

    So in comparison with this configuration:

    (1R, 2R)-----> yields enantiomers

    (1S, 1R)----> yields diasteromers


    So lets say that in comparison to the molecule you provided, the destroyer gave you the same molecule but both the bromine atoms were on were on solid wedges (coming out of the screen at you) or on dashed wedges (going behind the screen away from you), then those would be diastereomers.

    Once again, hope this helps and feel free to post any questions as I am studying (obviously browsing SDN) right now. Good Luck
     
  10. joonkimdds

    joonkimdds Senior Member
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    How can 3 ethyl cyclopentene can have 2 products that are diastereomer
    and cyclopentene cannot have 2 products that are diastereomer?

    Both of them are having Cl2 adds anti.

    The answer key says
    the product of 3 ethyl cyclopentene have more than 1 chiral center exists thus diastereomers are possible.

    I think the product of cyclcopentene also have more than 1 chiral center (2 because each carbon that are attached to Br are chiral), and don't know why diastereomers are impossible.

    Since we have (1S, 2S) and (1S, 1R) being diastereomers to each other, we have two diastereomer as products so shouldn't this be the right answer too?

    By the way, I didn't understand when you said "destroyer gave you the same molecule but both the bromine atoms were on solid or dashed wedges". I drew exactly what destroyer answer key says so both of them are not on same solid or dasshed wedges. One is dashed, one is wedged like I drew.
     
    #9 joonkimdds, Dec 25, 2008
    Last edited: Dec 25, 2008
  11. 5HTburb

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    No...

    Sorry for the confusion...

    The products of the reaction will yield a (1S, 2S) product and its enantiomer with the absolute configuration (1R, 2R). Which means that they are mirror images of each other, but not superimposible.
     

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