Stereochemistry Flashcards
Define the term of Isomerism?
They are compounds with the same atomic composition but with different structural or stereochemical formula and hence different physical and/or chemical properties
Distinguish the difference between structural isomers from stereoisomers
Structural Isomers:
Molecules with the same structural formula but different atom connectivity
Stereoisomers:
Molecules with the same structural formula, same atom connectivity but different orientation of their atoms in space
Define the term Geometric isomers?
They have different cis/trans configurations and result from restricted rotation about a bond
What is the CIP rule?
Each group attached to the double bond is assigned a priority ranking. Atoms with higher atomic numbers take priority over atoms with lower atomic number
Difference between cis/trans?
Cis are the same side groups placed on the same side of the double bond. Whereas Trans molecules have the same side group is placed on opposite sides of a double bond
What is E/Z nomenclature in relation to cis/trans?
E opposed to - trans molecules
Z together - cis molecules
Molecules should be preferred to cis/trans as the letter only applies to disubstituted alkenes
Determine the cis/trans configuration of cyclic molecules
trans (anti) and cis (syn)
The dashed group points down below the plane of ring. The blocked out group points up above the plane of ring
Define the term Enantiomers
Are pairs of molecules which are mirror images of each other and non-superimposable
What is a quaternary atom with four different substituents?
Stereogenic centre
How to identify if a stereogenic centre is R and S?
If the direction from substituent 1 to 3 is passing through substituent 2, clockwise the the stereo centre is R, if it anticlockwise it is S
How is a amino acid identified as D and L?
Can rotate the plane of polarized light to the right is D, and to the Left is L.
