Topic 1 - Stereochemistry Flashcards
(24 cards)
Composition
Number & Kind of Atoms
Constitution
Bonding pattern (which atoms are bonded)
Configuration
Spatial Relationship
- cis/trans
- E/Z
- R/S
- D/L
Confirmation
Variable spatial orientation
- think chair confirmations
Chiral
Cannot be superimposed on its mirror image. Has no plane of symmetry
Achiral
Can be superimposed on its mirror image. Has a plane of symmetry.
Racemic Mixture
Equal amount of each isomer - each enantiomer.
If all starting products are achiral and product is chiral - mixture is racemic.
How to create enantiomer?
- Draw mirror image
- Swap stereochemistry at each stereocentre
How to identify R & S
R - Clockwise 1,2,3
S - Anticlockwise 1,2,3
How to identify E & Z
E - high priority groups are on opposite sides of double bond
Z - high priority groups are on same side of double bond
Properties of achiral environments
Same physical and chemical properties
Properties of chiral environments
Different physical and chemical properties
What is the main property different between enantiomers?
They rotate light in opposite directions but of the same magnitude
What things are optically inactive?
- Racemic Mixtures
- Achiral Molecules
How to identify D & L
Compare the molecule to the structure of D and L glycer aldehyde
How to identify cis and trans
How to create distereomer?
Swap only one stereocentre
What is a mesocompound?
Has a plane of symmetry
Has 2 or more stereo-centres
How to determine the direction of bonds to substituents at each end of an allene (i.e. R-C=C=C-R)?
If number of double bonds in even
- one pair will be in line with plane and other pair will be orthogonal to plane of the page
If number of double bonds is odd
- both pairs of substituents will be in the plane of the page
How to seperate racemic mixtures
Substitution reactions
Elimination reactions
Confirmation Chemistry
Substitution or Elimination?
