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Stereoisomers are?
examples: __
- same atoms connected to same atoms pointing in opposite directions
- cis-trans
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Stereoisomers can be divided into what?
- enantiomers (mirror images are not superimposable)
- diastereomers (not mirror images; different physical properties; way different)
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Properties of enantiomers
same physical properties; identical with exception of smell and direction of optical rotation
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Presence of what gives rise to ability to form enantiomers?
What does it form?
- asymmetric center called chiral atoms
- chiral compounds
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Asymmetric center doesn't have to be __, but usually is.
In order to have a chiral center, what must you have?
- Carbon
- four different groups bonded to the carbon
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Chiral compounds and optical rotation?
will rotate in plain, polarized light
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Polarized light is what?
- waves are all synchronous; all coming at you
- plain polarized light will bind in a chiral compound
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True or False:
Not all tetrahedrals are chiral centers, but those with four different groups are.
True
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True or False:
You can only have one chiral center.
False: you can have more than one
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If you have one asymmetric carbon, you have __ stereoisomers.
Two?
Three?
What is the trend
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Stereocenters
any atom where interchange of any two groups gives you a stereoisomer
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Achiral compounds have what?
an internal plane of symmetry
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True or False:
Having a chiral center means you're chiral.
False: you can have a chiral center, but still have an achiral compound
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The presence of a chiral center does not necessitate __ or __.
- optical rotation
- chiral compounds
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Cyclohexanes
What can we say about them?
they switch chair conformations alot
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Trans compounds will have what?
a plane of symmetry
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Relationship between R and S and + and -
nothing
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If you have two chiral centers, what R and S configs can you have?
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Complexity arises when what?
- groups aren't halogens
- - rules develop
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Absolute configuration
term used to ask "is it R or is it S"
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Can chiral centers exist in rings?
yes
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When you have a tie and you look at the second bonded group, what can you do?
stop once the first atom differs; who cares if its a bigger molecule
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