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12 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What makes a carbon chiral?
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must have four different groups bonded to it
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R/S
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Mass number is highest (aka just look for highest element on periodic table)
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How do enantiomers differ?
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All different R/S values
Same physical properties of BP, MP, Density Optical activity is opposite but same absolute value |
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What do chiral compounds do?
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They rotate plane-polarized light!
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Racemic mixture
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50/50 mixtures of enantiomers, don't rotate light b/c they cancel each other out
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What are the two ways of separating enantiomers?
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1. Convert to diastereomers, separate, convert back to enantiomers
2. Chiral chromatography |
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Meso compounds
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Compounds containing chiral compounds, but are not chiral overall, must be plane of symmetry present.
If no stereochemistry shown (dashed/bold lines for back/forward)... |
can't tell whether meso or chiral
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Max number of stereoisomers POSSIBLE for a compound
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If n number of chiral compounds, 2^n POSSIBLE stereoisomers BUT SUBTRACT meso compounds from total
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Typical question: How many monochlorinated products, including stereoisomers, will you get when you chlorinate this compound?
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Test out all positions that give you distinct structural isomers and add chlorine at each.
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Fischer projections
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Every intersection is a chiral carbon. Vertical goes back, horizontal comes forward.
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Comparing two molecules drawn as line-angle and Fischer..
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Determine R/S
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Special stereochemistry for biological molecules
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sugars and amino acids are chiral
If amino group is on left of Fischer, L-amino acid. (natural form) If sugar has OH on right of last chiral carbon, D-sugar (natural sugar) |
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