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15 Cards in this Set
- Front
- Back
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Optical isomers may be
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Chiral or achiral
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Enantiomers
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Mirror images are NON superimposable, posses a chiral centre
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Diasterisomers
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(Non-enantiomers) ie not mirror images
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Number of sterioisomers
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2^n where n = number of chiral centres
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R/S naming
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1. Locate stereocentre
2. Lowest group points away 3. Read from highest to lowest priority (not including group behind the plane) |
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R
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R= clockwise
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S
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S= anticlockwise
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Mesocompound
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Contains a plane of symmetry and 2 or more chiral centres
Decreases number of stereocentre sod a compound Achiral - therefore not optically active |
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Racemic mixture
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Equimolar amounts of both enantiomers (optically inactive)
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Haloalkanes
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- polar R-X bond readily attacked by nucleophiles
Undergoes nucleophillic substitution and B-elimination |
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Sn1 mechanism
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- 2 steps
- C-X bond breaks to form a carbocation intermediate - favours more stable carbocation (3*>2*>1*>methyl) |
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Sn2 mechanism
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- 1 step
- bond breaking and bond formation is simultaneous - Nu- attack from backside - less crowded molecules favoured (methyl>1*>2*>3*) |
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B-elimination (Haloalkanes)
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Formation of alkenes from Haloalkanes
- occurs in the presence of a strong base - major product = most highly substituted molecule |
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Alcohol dehydration
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Conc H2SO4
- favours more crowded molecules (3*>2*>1*) |
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Oxidation of alcohols
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1* alcohol - aldehyde (via PCC) or carboxylic acid
2* alcohol - to ketones (PCC or H2CrO4) 3* alcohols cannot be oxidised |
