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Please help!! O chem question on Destroyer

Discussion in 'DAT Discussions' started by euphaire, Jul 30, 2011.

  1. euphaire

    euphaire Blank
    5+ Year Member

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    Hey all,
    I'm not sure about this two reactions in the picture I drew. they are part of the reaction mechanisms in question 77 and 78 in the destroyer.

    [​IMG]

    Can someone please tell me what's the name of this type of reaction so I can google it? I was thinking it's a E1 or E2. However, it can't be E2 because the base is not strong enough. It shouldn't be E1 either because E1 and Sn1 always compete and it's hard to make a reaction just do E1. So I'm really stuck and would like some help.
    In general, you have a halide, and you react it with RO-K+/ROH, what's the name of this reaction?

    Thanks :)
     
  2. radmazindds

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    These are elimination reactions. Both reagents in these reactions are likely to deprotonate. First off, they have a negative charge. Substitution is less likely here because these are BULKY bases. They don't want to go in anywhere they're not welcome so they take away instead.

    In the first reaction you have a Hoffmann elimination because the less substituted double bond is formed. In the second, it's a Saytzeff Elimination.

    Saytzeff elimination is the rule for E1. E2 can form a bit of both. (Jones, 2010)

     
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  3. rmm30

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    The SN1, SN2, E1, and E2 family of rxns is a constant on the DAT. It's the one family of reactions you are GAURANTEED to see on exam day. You need to know : Which substrates, which conditions, which solvents (to some extent) etc etc will react via these mechanisms. It is absolutely necessary that you know these 4 COLD.

    I don't think the best way to go about learning them is google either, bc they are all interconnected to an extent.
    Most textbooks do a great job of describing these in a way that is easy to understand. If you don't like textbooks and don't have lots of time, I implore you to get CHads videos. He will teach you all you need to know about Substitution and Elimination.

    They're not hard rxns. You'll probably get the hang of them quickly but they are nuanced. And you need to be able to spot little subtleties such as why the first rxn and the second reaction you listed react differently.
     
  4. yappy

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    Both were E2 right?

    1.)Large bulky base, protic solvent; giving the antimark

    2.)Base with tert substrate but protic solvent.

    RO- is a strong base.
     
  5. PooyaH

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    Yes strong bulky bases always result in an E2. And the second one is also a strong base and results in an E2.
     

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