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Organic chemistry- drawing optical isomers with aldehyde ketones. watch

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    Hi,

    I've just been doing an organic question about optical isomers however I've never drawn optical isomers of aldehydes and ketones before. Please could someone explain how to go about doing this (choosing the 4 groups and the chiral centre) as I can't understand the logic of what they've done from the markscheme.

    Thanks
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    (Original post by VioletPhillippo)
    Hi,

    I've just been doing an organic question about optical isomers however I've never drawn optical isomers of aldehydes and ketones before. Please could someone explain how to go about doing this (choosing the 4 groups and the chiral centre) as I can't understand the logic of what they've done from the markscheme.

    Thanks
    One important point is that the carbonyl carbon only has 3 things attached, so it cannot be the stereogenic (chiral) centre. That means one of the other carbons in the chain must be the centre, with 4 different groups. all you have to do is make sure you branch the carbon chain so that each bond from the chiral carbon has a different group attached.

    In this case each of those groups will be
    -H
    -CH3
    -CH2CH3
    ....etc.

    -CH=O (aldehyde)
    -COR (R is just an alkyl chain) (ketone)

    so the carbonyl makes no real difference to the drawing for the chiral centre, because it never is the chiral centre if that makes sense
 
 
 
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