Ch. 5 Flashcards
Stereoisomers
Differ in the ways the atoms are oriented in space
Enantiomers
Type of stereoisomer; Mirror Images
Diastereoisomers
Type of stereoisomers; Not mirror images
Achiral
Superimposible on mirror image
Chiral
Not superimposible on a mirror image
Tetrahedral Stereogenic center
A carbon atom with four different groups
Typically atoms with stereogenic centers are _______ and aroms with no stereogenic centers are _______
Chiral; Achiral
Stereogenic centers are those where the interchange of two groups gives a _______
Stereoisomer
What are the two different ways to draw an enantiomer?
- Draw a mirror image
- Switch two substituents on every stereogenic center
When labeling stereogenic centers, ____ is clockwise and _____ is counterclockwise
R; S
What formula determines how many diastereomers are possible?
2^n
How to draw all diasteromers
- Draw one stereoisomer, then it’s mirror image
- Switch the positions of one stereogenic carbon and draw its mirror image
A meso compound
An achiral compound that contains tetrahedral stereogenic centers (has a plane of symmetry)
Identical compounds have the _____ R S designations at every center. Enantiomers have ______ R S designations. Diastereomers have _______ R S designations.
same
exactly opposite
the same for at least one and the opposite for at least one other
Plane polarized light
light that has an electric vector that oscillates in a single plane
If you know the property on one molecule, its enantiomer has _______ properties
identical
In plane-polarized light, ______ rotates light and ______ does not rotate light
Chiral;Achiral
Two enantiomers rotate plane-polarized light in ___________ directions.
Equal but opposite
Specific rotation formula
observed rotation/(length of sample tube)(concentration)
Given information about a molecule, what do you know about it’s diastereomer
Nothing
How do you separate enantiomers
React them with acid to form diastereomers and filter in sand glass. One will move slower than the other and get stuck
