18 Questions
What defines diastereoisomers?
They are not mirror images of each other
In terms of symmetry, diastereoisomers can be:
Either achiral or chiral
How many stereogenic centres are present in each diastereoisomer compound?
Two
To convert one enantiomer to another, what needs to be inverted?
Both stereogenic centres
What is the key difference in converting diastereoisomers compared to enantiomers?
Only one stereogenic centre is inverted
Which type of stereoisomers contain structures that are mirror images of each other?
Enantiomers
What type of isomers are enantiomers?
Stereoisomers
If two isomers have the same connectivity but differ in the way the atoms are arranged, what type of isomers are they?
Enantiomers
Which type of isomers can be interconverted without breaking any bonds?
Constitutional isomers
How do enantiomers differ from diastereoisomers?
Enantiomers cannot be interconverted without breaking bonds
What is the main difference between conformation and configuration in stereochemistry?
Conformation involves different molecular arrangements, while configuration refers to bond connectivity.
In stereochemistry, what term describes molecules that can easily change their temporary arrangement by rotating around bonds?
Conformations
What is the main difference between enantiomers and diastereoisomers?
Enantiomers are mirror images of each other, while diastereoisomers are not.
How did chemists separate the trans epoxide from the cis epoxide?
By utilizing chromatography since they are diastereoisomers.
Why were both diastereoisomers racemic mixtures of the two enantiomers?
As a result of being made from achiral starting materials.
Why was it harder to separate the desired enantiomer of the trans epoxide?
Both enantiomers had identical properties.
Which type of stereoisomer is always chiral?
Enantiomers
How did chemists obtain only one enantiomer of the trans epoxide?
By developing new chemistry using enantiomerically pure compounds.
Study Notes
Isomers and Stereoisomers
- Isomers are compounds that contain the same atoms bonded together in different ways.
- Constitutional isomers differ in the connectivity of the atoms.
- Stereoisomers differ in the overall shape of the molecule, but have the same connectivity of atoms.
Enantiomers and Diastereoisomers
- Enantiomers are stereoisomers that are mirror images of each other.
- Diastereoisomers are stereoisomers that are not mirror images.
- Diastereoisomers can be achiral (have a plane of symmetry) or chiral (have no plane of symmetry).
Conformation and Configuration
- Two stereoisomers have different configurations, which means they cannot be interconverted without breaking a bond.
- Conformations differ only in the temporary way the molecule happens to arrange itself and can be interconverted just by rotating around bonds.
Assigning R and S Labels
- Stereogenic centres are labelled R or S using specific rules.
- Assigning R and S labels correctly is essential for understanding stereochemistry.
Converting Enantiomers and Diastereoisomers
- To go from one enantiomer to another, both stereogenic centres are inverted.
- To go from one diastereoisomer to another, only one of the two stereogenic centres is inverted.
Stereochemistry of Compounds
- When considering the stereochemistry of a compound, always distinguish the diastereoisomers first and then split these into enantiomers if they are chiral.
- Enantiomers have identical physical and chemical properties, making them difficult to separate.
Explore the concept of diastereoisomers, which are stereoisomers that are not mirror images and differ in relative stereochemistry. Learn about achiral and chiral diastereoisomers and how they can arise with multiple stereogenic centers.
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