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    I was wondering if anyone could help me with a few reaction mechanisms (see the attachment).

    We had to show how an electrophilic attack could take place.

    1. Would the double bonds to both oxygens break and allow two nucleophiles to attack both of the delta positive carbons and create two negatively charged oxygens with a single bond to the carbon.
    2. Would the positive oxygen just create a forth bond with the nucleophile, or would the carbon to oxygen bonds break and the nucleophile attacks. So it creates 2 x ethene, and Nu-O-H?
    3. Would one of the carbon to oxygen bonds break, creating a negatively charged oxygen, allowing a nucleophile to attack the carbon the bond broke from?

    Many thanks!
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    1. Nucleophile attacks C=O bond, causing an addition elimination and subsequent ring opening...
    2. Nucleophile attacks the carbon adjacent to the O+, electrons flow to the oxygen relieving the positive charge
    3. Nucleophile attacks the carbon adjacent to the O, causing ring opening
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    (Original post by EierVonSatan)
    1. Nucleophile attacks C=O bond, causing an addition elimination and subsequent ring opening...
    2. Nucleophile attacks the carbon adjacent to the O+, electrons flow to the oxygen relieving the positive charge
    3. Nucleophile attacks the carbon adjacent to the O, causing ring opening
    Why would the nucleophile attack the carbon adjacent to the O+, I thought it would of attacked the positive oxygen more then anything? And I don't understand how the first one is an elimination reaction...or how it opens the ring up?
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    (Original post by hidden088)
    Why would the nucleophile attack the carbon adjacent to the O+, I thought it would of attacked the positive oxygen more then anything? And I don't understand how the first one is an elimination reaction...or how it opens the ring up?
    Words are so clumsy :p:
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  1. File Type: pdf NuE.pdf (45.9 KB, 69 views)
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    (Original post by EierVonSatan)
    Words are so clumsy :p:
    Thank you Pictures are always better :yep:
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    Would this be right for the other mechanism? (excuse the bad drawing, the arrow to the oxygen looks like the 1 electron half arrow but its meant to be a full arrow )
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    (Original post by hidden088)
    Would this be right for the other mechanism? (excuse the bad drawing, the arrow to the oxygen looks like the 1 electron half arrow but its meant to be a full arrow )
    yeah looks good
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    I should of just drawn pictures in the first place
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    One last question if you don't mind. This time have to do the opposite, given the mechanism and have to show the products of it.

    This is the only one i'm not too sure about (i think the charges are wrong on it).
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    (Original post by hidden088)
    One last question if you don't mind. This time have to do the opposite, given the mechanism and have to show the products of it.

    This is the only one i'm not too sure about (i think the charges are wrong on it).
    charges the other way around - but otherwise okay
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    (Original post by EierVonSatan)
    charges the other way around - but otherwise okay
    Ok thanks! I always thought that the formal charge on the oxygen would be +1.

    Old Group Number (6) - Number of lone electrons (4) - No. Of Bonds (1) = +1
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    (Original post by hidden088)
    Ok thanks! I always thought that the formal charge on the oxygen would be +1.

    Old Group Number (6) - Number of lone electrons (4) - No. Of Bonds (1) = +1
    I haven't used formal charge in a very long time! Think of the electrons moving to the oxygen and then the positive magnesium coordinating to it (similar to how Li does in LiAlH4).
 
 
 
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