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Unformatted text preview: N C H C O H C O O C Procedure for Assignment of R, S Two Stereocenters: The Chlorination of 2Bromobutane Cl
Br Cl2, h_ -HCl * *
Br Generates: RR, RS SR, SS Four stereoisomers RR SS and RS SR are enantiomer pairs
Diastereomers Diastereomers are stereoisomers that are not image-mirror-image-related. The cyclic analogy: R,R (and S,S) = trans R,S (and S,R) = cis Assigning R,S in Cyclic Analogs Two Stereocenters with the Same Substituents
Br2, hv -HBr *
Br Same procedure: SS SR RS RR
Diastereomers The Mirror Plane in a Meso Diastereomer The Great Kudu Is Meso More examples:
* * CH3 CH3 but CH3 CH3 CH3 No stereocenters All cis-disubstituted cycloalkanes (with identical substituents) are meso (or have no stereocenters; e.g., any 1,4-disubstituted cyclohexane). The Cyclic Analogy: Meso is Cis Three S...
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- Fall '04