Chapter 6 Chirality Flashcards
What Are Enantiomers
are stereoisomers that are nonsuperposable mirror images
What makes enantiomerism so important?
Except for inorganic and a few simple organic compounds, the vast majority of molecules in the biological world show this type of
isomerism
What is the most common cause of enantiomerism among organic molecules?
a carbon bonded to four different groups.
What does Nonsuperposable mean
Not able to be overlapped onto another object such that all features match exactly
What does Superposable mean
Able to be overlapped onto another object such that all features match exactly
What is a chiral center
a tetrahedral carbon atom with four different groups bonded to it
What does achiral mean
If an object and its mirror image are superposable, then the object and its mirror image are identical, and there is no possibility of enantiomerism
An object that lacks chirality; an object that has no handedness and is superposable on its mirror image.
What does chiral mean
Objects that are not superposable on their mirror images (they show handedness)
What is a plane of symmetry
It is an imaginary plane passing through an object and dividing it so that one‐half of the object is the reflection of the other half
** occurs in achiral objects
What is a stereocenter
An atom at which the interchange of two atoms or groups of atoms bonded to it produces a different stereoisomer
What Is the 2^n Rule
for a molecule with n stereocenters, the maximum number of stereoisomers possible is 2^n
What are Diastereomers
are stereoisomers that are not enantiomers; that is, they are stereoisomers that are not mirror images of each other.
What is a meso compound?
an achiral compound that contains two or more stereocenters
**Note that the meso compound is a diastereomer of each of the other stereoisomers.
What Are the Properties of Stereoisomers?
Enantiomers=
Have identical physical and chemical properties in achiral environments. They have the same melting point, boiling point, same solubilities in water, the same values of pKa and they all undergo the same acid–base reactions.
They differ in optical activity (the ability to rotate the plane of polarized light)
Diastereomers=
Have different physical and chemical properties, even in achiral environment
Why are enantiomers optically active?
Each member of a pair of enantiomers rotates the plane of polarized light
